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1 DESIGN CODES FOR HEALTHY COMMUNITIES: THE POTENTIAL OF FO RM-BASED CODES TO CREATE WALKAB LE URBAN STREETS By GAIL MARIE HANSEN de CHAPMAN A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2008
2 2008 Gail Marie Hansen de Chapman
3 To my husband and my parents, for all their love and support
4 ACKNOWLEDGMENTS Many special people need to be recognized fo r their help and suppor t. I w ould like to express my gratitude to all my committee members, especially the chair, Professor Margaret H. Carr, first for encouraging me to pursue a doc toral degree, and second for her constructive critique and steady guidance. Many thanks go to my mentor and committee member, Dr. Joseli Macedo, also for inspiring me to pursue a degree, but mostly for her valuable insight and advice about those seemingly small, but critical items that helped me stay the c ourse. A heartfelt thankyou goes to my outside committee member, Dr. John Spengler, for his guidance on research methodologies and for being a calm and reassuri ng voice in the midst of confusion. I am also very appreciative of the time and effort of Dr Charles Hailey and Professor William Tilson for their helpful comments from their perspective on th e built environment. And last, but not least, I thank Professor Tina Gurucharri for her time and constructive observati ons. I found the positive and encouraging attitude of all my committee members to be as valuable as their scholarly advice and comments. A sincere thank you goes to Prof essor Robert Grist, chair of the landscape architecture department, for giving me the opportunity to teac h a course every semest er. I enjoyed working with the students, they are a great inspiration to me, and the teaching assistantships helped immensely with finances. I am also very grat eful for the help and friendship of my coinstructors, Professors Kay Williams and Gary Pu rdum. As always, it was a pleasure to work with them. I would like to thank all the people who participated in the interview for my study. Their participation was crucial to my study and they we re very much appreciated. Also, thanks go to all the planners and city officials who helped me secure the materials and information necessary
5 for data collection. Their enthusiasm for their work was infectious, and their comments that this study was needed were highl y motivating and inspiring. I would also like to thank sta ff members who were always helpful, friendly, and pleasant. A special thanks to Cindy Barton who always cheerfully helped w ith finances and all manner of confusing details, and to Juanita Melchior who helped with the multitude of forms and paperwork. I also greatly apprecia te the efforts of the staff memb ers at the Technical Helpdesk for their assistance and friendly na ture in those last days of template formatting madness. And finally, I would like to thank my hus band, Frank Chapman, for enthusiastically supporting my goal of obtaining a doctorate degree, and for alwa ys being patient and caring.
6 TABLE OF CONTENTS page ACKNOWLEDGMENTS...............................................................................................................4LIST OF TABLES................................................................................................................. ..........8LIST OF FIGURES.........................................................................................................................9ABSTRACT...................................................................................................................................10 CHAP TER 1 INTRODUCTION..................................................................................................................12Background Information......................................................................................................... 12Hypothesis..............................................................................................................................18Scope of Work.................................................................................................................. ......192 LITERATURE REVIEW.......................................................................................................21Introduction................................................................................................................... ..........21Health and the Built Environment.......................................................................................... 22Short History of Public Health and Urban Form.................................................................... 31Design of Walkable Streets.................................................................................................... 36Study of Environmen tal Aesthetics........................................................................................ 47Urban Design Standards and Codes....................................................................................... 52Aesthetic Codes and Walkable Streets................................................................................... 54Summary.................................................................................................................................583 MATERIALS AND METHODS........................................................................................... 60Information Sources and Assessment Tools........................................................................... 60Phase I: Walkable Street Surveys........................................................................................... 62Phase II: User Interview....................................................................................................... ..64Phase III: Form-Based Codes Assessment............................................................................. 674 RESULTS...............................................................................................................................70Data Collection.......................................................................................................................70Phase I: Walkable Street Surveys........................................................................................... 71Phase II: User Interview....................................................................................................... ..71Phase III: Form-Based Codes Assessment............................................................................. 73Summary.................................................................................................................................76
7 5 DISCUSSION.........................................................................................................................81Urban Design Quality Models and Form-Based Codes......................................................... 81Imageability Model.................................................................................................................83Complexity Model............................................................................................................... ...95Human Scale Model............................................................................................................. 106Enclosure Model................................................................................................................ ...117Transparency Model.............................................................................................................127Model Summary...................................................................................................................1346 CONCLUSIONS AND RECOMMENDATIONS............................................................... 147Study Strategy.......................................................................................................................147Using Urban Design Quality Mode ls for Code Development..............................................149Strengths and Weaknesses of Urban Design Quality Models.............................................. 151Strengths and Weaknesses of Form-Based Codes................................................................157Summary and Recommendations.........................................................................................1637 FUTURE WORK.................................................................................................................. 172Study Limitations.............................................................................................................. ....172Urban Design Qualities and Features................................................................................... 173Form-Based Codes............................................................................................................... .174LIST OF REFERENCES.............................................................................................................176BIOGRAPHICAL SKETCH.......................................................................................................183
8 LIST OF TABLES Table page 3-1 Form-Based codescity, state and title.............................................................................. 694-1 Average audit scores in each UDQ for Historic and FBC Streets..................................... 774-2 Number and percent of design feat ures cited by interview participants............................774-3 Number and percent of participants who cited validated and non-validated features....... 784-4 Percent validated and non-valida ted features cited by participants.................................. 784-5 Stratification of FB C and interview models...................................................................... 784-6 Stratification of aud it and interview models...................................................................... 794-7 Number and percent of FBCs th at regulate validated features.......................................... 794-8 Average percent of validated features regulated in each FBC........................................... 794-9 Stratification of audit and F BC models (validat ed features)............................................. 794-10 Number and percent of FBCs that regulate non-validated features...................................804-11 Average percent of validated and non-val idated features regulated in each FBC............. 804-12 Stratification of Audit and FBC Models (validated and non-va lidated features)..............806-1 Building faade zone........................................................................................................1666-2 Sidewalk and public space zone......................................................................................1676-3 Street zone................................................................................................................ ........1686-4 Landscaping................................................................................................................ .....169
9 LIST OF FIGURES Figure page 3-1 Map of Surveyed Communities.........................................................................................685-1 Imageability features...................................................................................................... ..1365-2 Imageability: sidewalk features...................142 5-3 Imageability: build ing features. ....................................................................................... 1385-4 Complexity features........................................................................................................ .1395-5 Complexity: sidewalk features......................................................................................... 1405-6 Complexity: building features.......................................................................................... 1415-7 Complexity: street features.............................................................................................. 1425-8 Human Scale features......................................................................................................1435-9 Human Scale: sidewalk features...................................................................................... 1445-10 Enclosure features........................................................................................................ ....1455-11 Transparency features..................................................................................................... .1466-1 Urban design qualities: sidewalk features........................................................................ 1706-2 Urban design qualitie s: street features............................................................................. 171
10 Abstract of Dissertation Pres ented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy DESIGN CODES FOR HEALTHY COMMUNITIES: THE POTENTIAL OF FORM BASED CODES TO CREATE WALKAB LE URBAN STREETS By Gail Marie Hansen de Chapman May 2008 Chair: Margaret H. Carr Major: Design, Construction, and Planning Form-Based design codes are a new planning tool being used by communities to create, livable, pedestrian-oriented urban environments. A possible li nk between physical activity, the built environment, and health has prompted a desire for healthy communities that support physical activity through urban design, including streetscapes that encourage walking as a means of transportation. The applicati on of Form-Based codes are prom oted, although not proven, as a means to create walkable streets because they control the street corr idor by regulating the physical features of the buildings, sidewalk and street that contribute to the urban design qualities of imageability, complexity, human scale, enclosure, and transparency. These features and qualities were identified as importa nt for walkability in a 2006 study; Identifying and Measuring Urban Design Qualities Related to Walkability by Reid Ewing, Susan Handy, Ross Brownson, Otto Clemente, and Emily Winston. The Ewing et al. study developed an audit instrument to measure each design quality and th e physical features that define it through their presence on the street. The audit was used to evaluate the Form-Based codes, and it was hypothesized that application of th e codes has the potential to cr eate a walkable urban street. Results support the hypothesis; an analysis of 30 Form-Based codes revealed the features
11 regulated by the codes created the same urban design qualities and features found on historic streets known to be walkable and preferred by user s. A survey of street s built by the application of the codes showed the codes have a greater poten tial to create walkable streets if they regulate a high number of features and control the frequenc y of the features within a designated length of street. Results also suggest codes are more likely to be successful if the majority of the regulated features are linked to the urba n design qualities of imageability, complexity, and human scale. Further study is recommended for several design qualities and environmental features identified, but not validated, in the Ewing et al. study, because results indicate their presence may enhance walkability.
12 CHAPTER 1 INTRODUCTION Have you ever seen Pearl Street in [Boulder] Colorado? Oh, ther es a huge park on one side of it. Its a very popular street. Ive been there only on ce, and I remember it very well. Its gorgeous, the architecture. Its very co mplex, a lot of things going on, as far as the street itself, and the buildings, old architectur e, old feel, a big green park. It changes from block to block, retail, older buildings, newe r buildings, all of a sudden a big huge open park and water and different level steps, cem ent and dirt, and grass and everything else, and then again, all retail. Even the retail busin esses, I remember a lot of them because it was just beautiful to look at. It was very, very pleasing to the eye, a lot of colors, a lot of different levels to look at. (Interview participant talking about a favorite walking street) A complex, aesthetically pleasing, pedestrian-frie ndly urban street is eas y to recognize, we know one when we see one. But a high-quality walkab le street is not always so easy to define, and even more difficult to codify and design. My study is concerned with the urban design qualities of a walkable street a nd the use of design codes to cr eate a pedestrian-oriented urban environment. The investigation centers on the de sign features that are regulated in a typical Form-Based code (FBC) and the potential of the codes to create a walkable urban street. An audit instrument from a recent study of the ur ban design qualities of walkable streets provided the framework to investigate the code poten tial and make recomm endations for code development. The results of the study suggest th at Form-Based codes do have the potential to create walkable urban streets if they regulate a high number of built features that create urban design qualities presumed to be re lated to walkable streets. Background Information Public health officials and community planne rs are beginning to question the relationship between ina ctivity, health, and the design of th e built environment. Many exercise specialists fear we have engineered phys ical activity out of our lives with sedentary work and environmental features that disc ourage physical activity. The lack of a suitable environment in which to be physically active is being investigated as a source of some of societys most
13 common health problems, particularly obesity and heart disease. The 1999-2000 National Health and Nutrition Examination Survey (NHANES) s howed that approximately 31% of the adult population was obese and 15% of children aged 6 to 19 years are overweight, while 60% of children aged 5 to 10 years manifest at least one cardiovascular disease risk factor (Frumkin, Frank, & Jackson, 2004; McCann & Ewing, 2003; Perdue, Stone, & Gostin, 2003). Exercise specialists advocate increasing lifes tyle or utilitarian activity, for example, walking, as the most promising approach to increasing physical activity (Peter s, 2004). Of particular interest is the ability to safely a nd comfortably walk in our communities, and the use of environmental modification to benefit all people exposed to the environment (Boslaugh, Luke, Brownson, Naleid, & Kreuter, 2004; Sallis, Baum an, & Pratt, 1998; Reed, Ainsworth, Wilson, Mixon, & Cook, 2004). The public health goal is to increase regular, moderate-intensity physical activity, mostly by walking in and around local neighborhoods (Reed et al., 2004). Although the 1996 Surgeon Generals report (U .S. Department of Health and Human Services [USDHHS], 1996) cited many studies showing the link between physical activity, and health, no study has shown a direct relations hip between health, physical activity and characteristics of the built environment (F rank, Eengelke, & Schmid, 2003; McCann et al., 2003). Studies do suggest, however, that the built environment impacts how and where we walk, and that the overall levels of physical activity are higher in walkable environments (Ewing, Schmid, Killingsworth, Zlot, & Raudenbush, 2003). A study by Frank et al. (2003) showed that in highly walkable neighborhoods people were 35% overweight and averaged 195 minutes/week of moderate physical activity, while people in neighborhoods with poor walking conditions were 60% overweight and averaged 130 minutes /week of moderate physical activity.
14 In May 2002, the National Center for Environm ental Health, Centers for Disease Control and Prevention (NCEHCDC) in Atlanta hosted a workshop to develop a scientific research agenda to study the relationship between the bui lt environment and the physical and mental health of the residents. Experts in the areas of physical activity, urba n planning, transportation, architecture, epidemiology, land use, mental healt h, social capital, housin g, and social marketing defined and described 37 questions to be considered for future research. Of primary concern was the effect that the design of communities ha s on physical activity. Noting that community characteristics, such as proximity to recreati on facilities, street desi gn, and housing density, can promote or discourage physical activity, the workshop pa rticipants wrote that design choices by planners and policymakers could improve public health in multiple ways. They proposed the following research question: What model codes (such as the SmartCode) already exist and how can one analyze model codes to assess their im pacts on health? (Danne nberg et al., 2003; p. 1506). The interest in the impact of design codes on health stems primarily from the potential of the codes to create an environment that encour ages, rather than discourages, physical activity, particularly the ability to create a community where walking is common fo r utilitarian purposes. The emergent research agenda is concerned with the concept of walka bility, a term used to describe conditions in the built community that encourages walking (Brownson, et al. 2004; Carnegie, et al. 2002; Giles-Corti & Donovan, 2003; Leslie, et al. 2005; Southworth, 2005). Walkability is a term that is used frequent ly, but it is not well de fined. Southworth (2005) offered the following definition for clarifica tion, which is adopted for this paper: Walkability is the extent to which the built environment supports and encourages walking by providing for pedestrian comfort and safet y, connecting people with varied destinations within a reasonable amount of time and effort, and offering visual in terest in journeys throughout the network. (p. 248)
15 Neighborhoods are generally consid ered pedestrian-oriented if they have high densities and mixed land use with a highly connective, human-s cale, street network and desirable aesthetic qualities. But the connection of some of these conditions to walkability is based more on intuition rather than empiri cal testing (Handy, Boarnet, Ew ing, & Killingsworth, 2002; Owen, Humpel, Leslie, Bauman, & Sallis, 2004). Other hypothesized characteristics that might encourage walking include sidewalks and street design, such as street width, paving materials, and signage (Brownson et al., 2004; Hoehne r et al., 2005; Leslie et al., 2005). Few studies have evaluated the effects of street level (sidewalks and street) characteristics, and little consensus exists on the relative importan ce of the aesthetics, such as visual details, landscape features, and spatial re lationships on the desirability of places for walking (Hoehner, Ramirez, Elliot, Handy, & Br ownson, 2005; Zacharias, 2001). Some of the factors that contribute to aesthetic qu alities include varied ar chitecture with small-scale detail, transparency (windows) in the fronting structures, landscapin g with street trees, ch anging vistas, street furniture, and pedestrian lighting--all qualities that contribute to a strong sense of place (Handy et al., 2002; Southworth, 2005). The aesthetic characteristics include items that are difficult to assess both qualitatively and quant itatively, and in the past they have typically been described rather than measured (Zacharias, 2001). Re search has shown, however, that measurement techniques based on the materials, geometric re lationships, location in space, and frequency within a defined area can be used to describe and quantify aesthetic quality (Stamps, 2000; Van der Laan, 1983). Of particular interest from a designers persp ective are questi ons about how a users perception of the environment influences walking behavior, especially on issues such as the sensory experience, physical comfort, and th e visual and auditory experience (Zacharias, 2001). Environmental psychologists se parate the aesthetic qualities into two cat egories. The first
16 category is the physical (measurable ) qualities that collectively contribute to the second category, which is the experiential (perception and preference) quality (Ataov, 1998; Lang, 1987; Porteous, 1996; Purcell, 1986). Research has sh own (a) common architectural perceptions and preferences among the public, and (b) urban design preferences can be described through measurable physical qualities or design features (Ataov, 1998). The ability to measure physical qualities and user preferences are important concepts for the application of design codes, such as Form-B ased codes (FBCs), to the creation of walkable streets. As the name implies, Form-Based codes regulate the form and visual quality of the street through description and measurement of the design features. A primary goal of Form-Based codes is the creation of urban stre ets that will encourage a high le vel of pedestrian activity. The codes typically regulate design feat ures that relate to user pref erences for public spaces (Katz, 2004). Preconditions and Assumptions Although few studies exist on aesthetic quality a nd the visual experien ce of the street, a recent study by Ewing, Handy, Brownson, Clemente, and Winston (2006) sought to identify and measure urban design qualities that relate to walkability. A final report was produced by the team of Ewing, Clemente, Handy, Browns on, and Winston (2005) titled: Identifying and Measuring Urban Design Qualities Related to Walkability, Final Report (retrieved April 12, 2007, from http://www.activelivi ngresearch.org/node/10636 ) In the intro duction to the Final Report the authors state: Physical features of the built environment infl uence the quality of the walking environment both directly and indirectly through the perceptions and sensitivities of individuals. Our study focuses on urban design qualities, qual ities of the environment that depend on physical features.All of these factors--phy sical features, percep tual qualities, and individual reactions--influence the way an individual feels about the environment as a place to walk. (p. 1)
17 The results of the Ewing et al (2006) study were also used to develop a field manual titled Measuring Urban Design Qualities: An Illustrated Field Manual (Clemente, Ewing, Handy, Brownson, & Winston (n.d.), and an audit instrume nt (score sheet) that is accessible to other researchers for continued studies on the urban design qualities of a walkable urban street (retrieved April 12, 2007 from http://www.activelivingresearch.org/node/10635 ). The Field Manual and Final Report from the study provided a precondition and foundation for my study. Based on Ewing et al.s (2006) lite rature review, the study focused on eight urban design qualities (UDQs) that appeared to be va lued by users of urba n spaces: imageability, legibility, visual enclosure, human scale, tr ansparency, linkage, complexity, and coherence. Using expert opinion, statistical analysis, and field testing, th e research team ultimately developed definitions and protocols for five of the design qualities: enclosure, transparency, human scale, complexity, and imageability. They subsequently develope d the Field Manual and audit instrument that include instructions for rating an urba n street for walkability by quantitatively measuring certain features related to the five urban design qualities. The manual and score sheet provided a framew ork within which to study design codes and the streets that are built from these codes. My study assumes that the audit instrument is a legitimate tool for assessing the walkable qualities of a street, based on the scientific rigor of the study from which it was developed. My study also used historic streets as the gold standard to comp are audit scores for walkable qualities. Using historic streets was assumed to be a legitimate standard based on the reputation and qualifications of the organization (Walkabl e Communities, Inc.) that judged the historic streets to be highly walkable.
18 Rationale and Objectives One reason for studying the walkab ility of community streets is the public health goal to increase utilitarian physi cal activity, which is based on the theo ry that people might walk more if the built environment encouraged physical activit y. Another reason is to study the visual quality of streets, which is important to designers for development of standards and codes, and also to policymakers for the establishmen t of design policy (Ataov, 1998). Policymakers in many communities are moving beyond the concept of design guidelines to aesthetic codes, such as FBCs, to preserve the character of their towns and to make them more livable and walkable. Planners and designers are advocating the codes as an effective tool for achieving their goals for walkabil ity. Community officials see FBCs as a viable legal method to control the aesthetic appearance of their community. Although planners know how to develop, write, implement, and enforce the codes, the question remains about th e codes potential to achieve the communitys goals for walkability (Watson, 2001). The three objectives of my study are to analyze (a) streets that ha ve been created by the applica tion of FBCs, (b) the Form-Based codes that were used to create the streets, and (c ) the users observations of the FBC streets to establish the relationship between the streets and the codes. Hypothesis The core concept of m y study is that well-cr afted design codes can cr eate an urban street that will encourage a high level of pedestrian ac tivity. This concept is based on the fundamental aspect of code and policy devel opment for aesthetic control, which is the notion that physical design and aesthetic qualities can be measured, described, and quantified. It is also based on a primary goal of the codes, which is to shape a high-quality, walkable public realm (Katz, 2004; Lewis, 2004; Nasar, 19 94; Ulrich, 1983). The core concept for this
19 study is further refined to specify that Form-Based codes can create an ur ban street that will encourage a high level of pedestrian activity. Scope of Work Data collection for m y study occurred in th ree phases using thr ee methodologies. Phase I included a visual survey (audit) of historic a nd FBC streets in different communities. Phase II was an interview with users (business owners) from an historic street and a FBC street that were surveyed in the Phase I audit. Phase III consisted of a review and summary of data from the written Form-Based codes. Phase I: Street Survey The intent of the Phase I audit of the historic walkable streets was to provide the initial framework, a stratified set of UDQs, on which to organize and inve stigate the research question. The Phase I audit of the FBC streets compared the urban design qualities of FBC streets to the UDQs of the historic streets. This comparison was used to find out if the streets shared similar urban design qualities, and also to determine if the UDQs used in the audit provided a reasonable framework for predicting the potential of FBCs to create walkable streets. My studys premise was if the audit scores showed that the same UDQ features appear on both the FBC streets and the historic walkable streets, then the codes are regulating the same features found on historic walkable streets. The implication would follow that FBCs have the potential to create walkable urban streets that are comparable to known walkable streets. Phase II: User Interviews The Phase II interviews were conducted to i nvestigate which features and UDQs the users perceive to be meaningful for a walkable street compared to th e features regulated by code. My studys premise was that if the features of value to the users are present in the codes, then the
20 codes have the potential to create a walkable street both from the everyday users perspective and the design professional (c ode writers) perspective. Phase III: Form-Based Code Review To find out if the codes were in fact regulating th e features found on the FBC streets and to determine the UDQ most influenced by the FBCs, a review of 30 codes (including those of the audited streets) was completed in Phase III. Th e review was used to investigate the assumption that the codes are regulating the same features that create the UDQs found on the historic walkable streets. If the codes do regulate the same features found on historic walkable streets this would explain how the FBCs can create streets that are walkable.
21 CHAPTER 2 LITERATURE REVIEW Introduction The study of the relation ship of the built envi ronment to physical health is complex and requires consideration of a wide range of issu es. The first section of the literature review, Health and the Built Environment, examines st udies concerned with the link between physical activity behaviors, the built environment, and health. The discussion includes the distinction between walking for transportati on and recreation and also comm unity design as it relates to walking. The second is a brief history of the relati onship between public health and urban form. This section includes the early theories and st udies that linked health to urban form, the contributions of planners and la ndscape architects, the first use of codes and zoning ordinances to improve health, and the impact of the Garden C ity Movement on present-day suburban form. The third section, Desi gn of Walkable Streets, describe s the aesthetic design qualities of streets, such as enclosure, human scale, transparency, complexity, and imageability, as they relate to the street form and the preferences and walking behavior s of the pedestrian. The fourth, Study of Environmental Aesthetics, focuses on the aesthetic response: the study of emotional appraisals and preferences for the environment and how people respond behaviorally to visual quality. This section describes the models used to study the re lationship between measurable physical qualities and expe rience of the users. The fifth section, Urban Design Standards and Codes, discusses the use of codes to control aesthetics and the issues with writing code s that describe and quantify aesthetics based on subjective design qualities. The la st section, Aesthetic Codes and Walkable Streets considers the use of Form-Based codes, which are new types of codes that regulate form rather than use, to
22 develop streets that are pedestrian-oriented. Th e codes include standards for the appearance of buildings, sidewalks, and streets with the primar y purpose of creating a wa lkable public realm. Health and the Built Environment Interest has grown in how the relationship betw een inactivity, health, and obesity m ight be affected by the design and form of the built envi ronment. One area of concern is the effect of urban sprawl (distance to des tinations) and automob ile dependency on walking. Another is the effect of urban design characte ristics, both aesthetic and f unctional, on walking behavior. Link Between Physical Activity and Health Although research has shown an established and solid relationship between physical activity and chronic disease, no study has shown a direct relati onship between obesity, walking, and characteristics of the built environment (E wing et al., 2003; Frank et al., 2003; McCann et al., 2003). The 1996 U.S. Surgeon Generals report, Physical Activity and Health (USDHHS, 1996), showed that moderate physical activity re duced the risks of developing or dying from some of the leading causes of illness. The repor t found that regular physic al activity can improve health by reducing the risk of co ronary heart disease, stroke, co lon and breast cancer, premature death, osteoporosis, non-insulin-d ependent diabetes, and high bl ood pressure. Physical activity can also help reduce feelings of depression and promote psychological well-being (USDHHS, 1996). The health-related components of physical fitness include cardi ovascular endurance, flexibility, muscular strength, muscular endu rance, and body composition. The mechanisms by which physical activity can reduce various risks is by improving cardiovascu lar health, including blood lipid and cholesterol profiles, lowering blood sugar, and blood pressure, controlling weight, and helping to maintain and increase bon e density and strong muscles and joints (Evans, 1987; McArdel, Katch, & Katch, 1981; Stokes, Moore, & Moore, 1988).
23 Obesity has been a major focus of health a nd physical activity studies because it has been associated with many of the chronic health pr oblems previously mentioned and it is directly affected by physical activity. A recent study by the Ra nd Institute reported that obesity is more strongly linked to chronic diseases than drinki ng, smoking, or living in pov erty (Hill, Wyatt, Reed, & Peters, 2003). Obesity in the United Stat es has reached epidemic proportions both in adults and children. The 1999-2000 National Hea lth and Nutrition Examination Survey (NHANES) showed that approximately 31% of the adult population was obese, with a body mass index (BMI) greater then 30 kg/m, and 65% were overweight with a BMI greater than 25 kg/m. Body mass index is a measure of weight in relation to height to gi ve an index of healthy weights for a given height (divid e body weight in kilograms by s quare of height in meters). Measures above 25 kg/m are considered overweight above 30 kg/m are considered obese (Hill et al., 2003). Studying children aged 6 to 19 years, 15% are overwe ight, and 60% of 5 to 10 yearold-children manifest at l east one cardiovascular disease risk f actor. It is also estimated that onethird of all U.S. children will develop type II diabetes (Frumk in et al., 2004; McCann & Ewing, 2003; Ewing et al., 2006; Perdue et al., 2003). Prevention of weight ga in or minor weight loss in high risk groups has been shown to be very effective in preventi ng the development of hypertension, type II diabetes, a nd cardiovascular disease (Gill, 2002). Physical inactivity and excess weight now account for more than 300,000 premature deaths each year. Among preventable causes of death, complications due to obesity are second onl y to tobacco-related deaths (Ewing et al., 2003). Obesity has many causes, including an environment that promotes excessive food consumption and a sedentary lifestyle. While we can identify the characteristics of our environment that promote eating, it is not as easy to define the characteristics that discourage
24 physical activity (Peters, 2004). We have engine ered physical activity ou t of our lives with sedentary work, leisure time, and environmental features that discourag e physical activity. The median weight gain in the adult population is two pounds per year. A positive energy balance of 100 calories a day can explain the weight gain of 90% of the population. Walking an additional mile each day would burn the approximately 100 calor ies (kcal) that cause weight gain (Peters, 2004). Research shows that activity does not have to be strenuous to achieve health benefits. People who are inactive can impr ove their health through modera te activity on a regular basis (USDHHS, 1996). Choosing an activ e lifestyle or utilitarian physical activity, as opposed to leisure time or recreational physical activity seems the most promising approach. The public health goal is to increase moderate-intensity physical activity and for most people walking in local neighborhoods is the most real istic activity (Reed et al., 2004). The guidelines of the U.S. Department of Health and Human Services (USDHHS) recommend that adults get a minimum of 30 mi nutes of moderate-intensity physical activity (PA), five times a week or more and that child ren get 60 minutes of age-appropriate physical activity. However the guidelines for weight loss are higher, with a recommended 60 to 90 minutes of PA, five to seven times a week. A moderate amount of physical activity uses approximately 150 calories of energy per day, or 1,000 calories per week. Activities that fall into the moderate-intensity category include walking (1.75 miles in 35 minutes to 2 miles in 30 minutes) and bicycling (5 miles in 30 minutes or 4 miles in 15 minutes). The calories expended depend on the intensity and fitness level of the pe rson. Currently more than 60% of adults do not achieve the recommended amount of activity a nd 25% are not active at all (USDHHS, 1996).
25 Link Between Community Design and Health Two main branches of research link physic al activity and the built environment. One branch focuses on physical activity from the public health perspective, which is generally recreational physical activity. The other branch looks at physical activity (walking and bicycling) from the urban planning and transportation perspective, which is utilitarian physical activity (secondary to other goals). Considering physical ac tivity from the two perspectives is important because characteristics of the built environment th at facilitate or constrain physical activity may depend on the purpose of the activity (Ewing et al., 2006). The built environment influences both perspe ctives, particularly utilitarian physical activity, which is the ability to commute by foot, bicycle, and tran sit (transit users walk more). Characteristics that impact utilita rian trips include the proximity of destinations, linkage of path network, design of the streetscape, and availability of motorized transport. Characteristics that influence leisure and recreation trips include the presence, desi gn, and aesthetics of recreation facilities and streetscape, perceptions of safe ty, and other people bei ng active (Ewing et al., 2006; Hoehner et al., 2005; McCann & Ewing, 2003; Northridge & Sclar, 2003; Owen et al., 2004; Pikora, Giles-Corti, Bu ll, Jamrozik, & Donovan, 2002). Most of the recent studies that link community design to health have focused on urban sprawl because the characteristics of sp rawl appear to impact physical activity (McCann & Ewing, 2003). Ewing et al. (2003) defined sprawl as an environment characterized by (a) a widely dispersed population in low density developm ents; (b) a strict separation of uses such as commercial, home, and work; (c) lack of a distin ct activity center such as a downtown; and (d) lack of connectivity thro ugh a network of roads.
26 An association exists between urban sprawl and driving that suggest s a potential pathway of causality between urban sprawl and poor health : Urban sprawl leads to increased automobile use, which leads to decreased phys ical activity, which leads to obe sity, which leads to increased cardiovascular disease, diabetes and othe r chronic health problems (Lopez, 2004). One study looked at physical activity as reported by the Behavior Risk Factor Surveillance System (BRFSS) for three years in 448 counties and 83 metropolitan areas; each county and city was scored on the sprawl index. The study found that more sprawl was clearly associated with less walking. Also, as the level of sprawl increased, so did hypertension, body weight, and probability of being obese (McCann & Ewing, 2003). In a study by Frank et al. (2005) to link objectively measured physical activity with objectively measured urban form, using the Strategies for Metropol itan Atlantas Regional Transportation and Air Quality (SMARTRAQ) questionnaire, measures of land use mix, residential density, and intersection density were positively related with the number of minutes of moderate physical activity per day. Data fr om the Atlanta region showed significantly lower obesity rates for those who reside in more compact, denser, pedest rian friendly, transitoriented communities. Studies have found similar results when looking at the association between the urban form (land use and distance walked) and the probability of being overweight. While these studies do not affirm causality, th e results lend support to the limited evidence linking urban form with activity levels and obesi ty (Ewing et al., 2003; Fr ank et al., 2004). Other constraints to physical activity in the environmen t include safety (both from crime and traffic), weather, and lack of facilities and opportunities (Frumkin et al., 2004).
27 Components of Walkable Communities For physical activity, the most important issues related to sprawl are two core land use concepts-density and land use mix and two co re transportation concepts-automobile dependency and connectivity (Frumkin et al., 2004). The density and land use mix concept measures the degree of proximity-or the functi onal distance between where we live, work, and play-that has implications for travel behavior. High density is usually associated with shorter trips, increased transportation options, and reduc ed vehicle ownership. Although higher densities are often correlated with a high number of destinations, a highly dense area could have few trip destinations. However, a high level of both la nd use mix and density typically produces a high number of destinations (Frank et al., 2003; Frumkin et al., 2004). Studies show that the distance to destinations is an important factor that affects whether or not people decide to walk. Distan ce is more of a determinant th an weather, physical difficulty, safety, or fear of crime. Having close destinat ions proved to be the strongest correlate of transportation walking (Hoehner et al., 2005; So uthworth, 2005). Pedestrians will choose the shortest path and, for that reason, reducing tr ip distances is a cri tical reason for links (connectivity) within a larger network (Ech everria, Diez-Roux, & Link, 2004; Reed & Ainsworth, 2002; Zacharias, 2001). Physical proximity is also a major factor in trail use. Recreation trai ls have been found to be a useful environmental a nd policy intervention to promote regular activity (Reed & Ainsworth, 2004). Neighborhood variab les are stronger predictors of physical activity and walking than community variables, suggesting th at interventions should target neighborhood or proximal locations (Addy, et al., 2004).
28 Although a compact community is desirable, no known level or critical threshold of compactness of community design exists wher e there is a measurable influence on physical activity (Ewing, Frank, & Kreutzer, 2006). The automobile dependency and connectivity concepts are concerned with highly connected travel routes and s horter distances. Connectivity aff ects how destinations are linked. Well-connected systems, such as the grid pa ttern, shorten the ground distances with more intersections (Frumkin et al ., 2004). Alexander et al. (1977) and Jacobs (1993) recommended street connections and pedestri an crossings every 200 to 300 f eet, although others (Appleyard, 1981) argued that too much connectivity can in crease traffic and decrease walkability. A healthy community has a combination of components that promote physical activity. Neighborhoods are more pedestrian-o riented and people tend to walk and bike more if they have high densities of development, mixed land use (retail, commercial, a nd residential), a high connectivity street network with many intersectio ns and shorter blocks, human-scale streets in spatial and built form, and desirable aesthetic qualities (Boslaugh et al., 2004; Handy et al., 2002). The Centers for Disease Control (CDC) define Active Community Environments (ACES) as places where people of all ages can easily participate in physical activity. The hypothesized ACES model is as follows: Active Community Environments (walkable and safe) leads to greater physical activity which l eads to lower obesity which le ads to fewer weight-related chronic conditions which leads to better overall health. Studies by Doyle, Kelly-Schwartz, Schlossberg, and Stockard (2006) and Frank et al. (2003) provided some support for this model. They found that individuals who live in counties that have bett er walking conditions and lower rates of crime tend to walk and exercise more averaging 195 minutes/week of physical activity.
29 These individuals have lower body mass indices (35% overweight) than pe ople in counties with poor walking conditions and more crime-prone areas. This latter group of people averaged 130 minutes/week of activity and was 60% overweight. Walking Behavior Other factors that influence walking behavi ors include demographics (socioeconomics, age, race, and gender) and individual lifestyles (attitudes and beliefs, behavior and skills, and social and cultural issues) (Frumkin et al., 2004). The most common personal barriers to exercise are lack of time (real and perc eived), physical inability, lack of motivation, lack of social support, fatigue, childcare res ponsibilities, and l ack of knowledge (Frank et al., 2003). Attitudes and preferences are also important in the travel choices made by individuals. Many choose to drive short distances rather th an walk. The national Personal Transportation Survey (1984) found that 70% of people will walk no more than 500 feet for daily errands, 40% will walk one-fifth of a mile, and only 10% are willing to walk a half mile. A study by Southworth (2005) showed similar results: 10% w ill walk up to a half mile (approximately 8-10 minutes), but most will only walk a distance ranging from 400 feet to a quarter mile. Studies revealed that in sprawling metropolitan areas, 41 % of all trips were shorter than two miles and 28% shorter than one mile, yet Americans use thei r cars for 66% of trips up to a mile and for 89% of trips between one to two miles. In the Un ited States only 9% of total trips were by foot and 84% were by car in 1990 (Pucher & Dijkstra 2003; Southworth, 2005). Even when walking is feasible, many prefer to drive. More research is needed on how the distance people are willing to walk is impacted by design f eatures (Frumkin et al., 2004).
30 Determinants of Walkability Walking can be for exercise, pleasure, or tran sport, and the environment in which walking typically takes place can be desi gned with pedestrians in mind (Les lie et al., 2005). Strategies to modify the environment are particularly important because they can benefit all people exposed to the environment, which may be more effectiv e and cost-efficient than individual behavior modification (Boslaugh et al., 2004; Reed et al., 2004; Sallis et al., 1998). Studies have shown that individually focused inte rventions have not created longterm change or population-wide change, and they are not cost-eff ective (Saelens, Sallis, Black, & Ch en, 2003; Sallis et al., 1998). A proposed framework for classifying determ inants of walkability includes four categories: functional, safety, destinations, and aesthetics. Fu nctional includes the physical attributes of the street or pat h, such as width and continuity. Sa fety includes street crossings, lighting, and passive surveillance (eyes on the street ). Destinations include parks, transit nodes, stores, and restaurants. Aesthetics refers to the attractiveness or appeal of the place (Frank et al., 2003). Of the four categories, the aesthetic qualities are the most intangible and are typically described rather than quantitatively measured. So me of the factors that contribute to aesthetic qualities include building design (windows and doors), landscaping, paving materials, street trees, benches, signage, and lighting, which are all qualities that contribute to a strong sense of place (Brownson et al., 2004; Handy et al., 2002; Hoehner et al., 2005; Les lie et al., 2005). Few studies have evaluated the effects of these street level characteristics or lo oked at issues such as the quality of the elements. Little consensus exis ts on the relative importanc e of the visual details and landscape features, or the spatial relationshi ps on the desirability of places for walking (Hoehner et al., 2005; Zacharias 2001).
31 Only a small body of evidence exists on how best to measure the users perceptions of the environmental factors for walkability (particu larly neighborhood) and how these perceptions may be related to objectively evaluated elements (Leslie et al., 2005; Saelens et al., 2003). Of particular interest from a designers perspec tive are questions about how perception of the environment influences walking be havior, especially on issues su ch as the sensory experience, physical comfort, and the visual and auditory experience (Zacharias, 2001). In studies that compared residents perception of walkability, a significant difference can be seen between ratings of thos e who live in high and low walkable areas for density, landuse mix, street connectivity, a nd infrastructure for walking. Residents in high walkability neighborhoods spend about 70 more minutes in moderate-intensity physi cal activity during the week than residents in low walkability nei ghborhoods. The residents in the high walkability neighborhoods reported spending more time walking for errands and during breaks at work or school (Leslie et al., 2005; Echeverria et al., 2004; Saelens et al., 2003). Short History of Public Health and Urban Form Public hea lth and the built environment have been linked for centuries in one form or another, but a once strong rela tionship has diminished in recent years. Contemporary health problems are bringing renewed interest in the form of the built environment as it relates to health. Traditional Link The traditional link with the built environment a ddressed health issues, such as sanitation, infectious diseases, toxic wastes fire codes, workplace safety, lead paint, and accessible design (Jackson, 2003). Early cities posed many threats from sanitary problems such as garbage, noxious trades (tanning, slaughtering, etc.), se wage, crowded housing, and contaminated water and air. These conditions led to high rates of in fectious diseases (Frumk in et al., 2004). Health-
32 based zoning laws were enacted as the primar y intervention to allevi ate most of the placeoriented health problems. For example, zoni ng laws, which blocked high density work-live developments, helped prevent the spread, but not the cure, of infectious diseases by proximity (Jackson, 2003). From 1793 to 1806, yellow fever was the scourge of cities. It was during this time that quarantine stations, local health officers, and loca l health agencies (referred to as committees on health or boards of health) were establishe d. They became the forerunners of todays U.S. Public Health Service (Frumkin et al., 2004). In 1798, Valentine Seaman, a surgeon at New York Hospital, began to investigate the yellow fever outbreak in his city. He argued that the origin of th e outbreak was the smell (putrid miasmata) from the citys garbage and sewer in the harbor area. Alt hough this was a commonly held belief at the time, he was the first to use maps to show the yellow fe ver cases in relation to the location of the waste and sp atial configuration of the built environment. By pinpointing the outbreak of cases in certain low lying areas wher e water and sewage collected, he was able to connect disease to the built form, and he argued that the environment itself was in need of repair. In 1819, Felix Pascalis mapped yellow fever outbreak s in New York by order of occurrence. By mapping the range of urban cases he made an argume nt that the foul air caused the disease rather than simply conveyed it. He used his maps to ma ke a case for an urban sanitation infrastructure. Although it would be another century and the inve ntion of the microscope to disprove the miasmatic theory of disease, Seaman, Pascalis and other New York Board of Health researchers were the first to connect the ur ban form to health (Koch, 2005). In the 1840s, Edmund Chadwick, the head of the London Board of Health, mapped the incidence of cholera, poverty, a nd population density per acre, t hus showing the relationship of
33 class and place to the incidence of health a nd disease (Koch, 2005). At the same time, John Snow, a London physician, was working in the hardest hit areas of London when he began mapping cholera locations. Snow put forth the theory that cholera was introduced into the area through the water, not air, and passed through person-to-person contact. This was a radical and controversial argument that implicated the privat e and city waterworks that drew their water from the Thames River. His South London study in 1855 of the Broad Street water pump area showed the relationship of deat hs to real travel time from the well. The map, presenting the twisted and often truncated street s of London, demonstrated that t hose with the shortest walking distance to the well (most frequent users) had the higher incidence of death, thus connecting behavior influenced by the bui lt environment to health (K och, 2005). Snows study again highlighted the connection between the built e nvironment and health. Although he failed to convince his contemporaries of his argument, this now famous study made John Snow the patron saint of the disciplines of pub lic health and epidemiology (Koch, 2005). In 1864 the Council of Hygiene and Public Health in New York issued a report on the rate of illness and sanitary infrastructure that lead to the passage of the landmark New York Metropolitan Health Bill of 1866, which created a board of health to oversee sanitation in the city (Frank et al., 2003). In 1874, the American Public Health Association began a campaign to clean the air in Charleston, South Carolina, and other cities followed, beginning the sanitation reform movement (Frumkin et al., 2004). Sanitation Reform The time between the mid-1800s and the mid-1900s was a period when a wide range of architects, planners, activists, po liticians, and other pr ofessionals sought to improve the chaotic, unhealthy city of the industrial er a. Public health concerns led to the idea of the horizontal city
34 with decentralized settlement patterns. Four different periods underscore the importance of health in the shaping of urban form: sanitati on reform, tenement housing reform, establishment of zoning as a standard planning t ool, and evolution of the garden city in city planning (Frank et al., 2003). In addition to the medical community, the san itation reform movement involved architects, planners, and landscape architects. The most significant contributions were made by Fredrick Law Olmsted, a landscape architect who planned and designed several suburbs, led the urban parks movement, and published widely on the h ealth of urban dwellers and urban form. As Secretary of the U.S. Sanitary Commission, he wrot e that the health of urban dwellers could be improved by abandoning the compact building of towns and adopting a custom of laying them out in a larger space for air and sunlight. He advocated wide boulevar ds, street trees, urban parks, lot and building redesign and satellite suburbs as the id eal urban form-a solution that presaged the 20th century American city (Frank et al., 2003). Tenement Housing Reform Although the bacteriologi cal revolution downplayed the cont ribution of local conditions to disease, housing reformers in the Progressive Era (1900-1914) continued to attach great importance to health of urban dwellers, focusi ng on the triple threat of poverty, unsanitary housing and overcrowding. Frank Veiller, chair of the New York Tenement House Commission, fought for limitations on building heights, lot dept h, block sizes, street la yout, and zoning for the entire city. His codes set the stage for New York s first zoning ordinance and became the basis for housing codes across the United States. The idea th at high density of stru ctures contributed to unhealthy living became institutionalized duri ng World War II when the Federal Housing Administration developed m odel subdivision and health codes (Frank et al., 2003).
35 Land Use Zoning Proponents of zoning believed it was a way to im prove the health of urban residents. But unlike housing reformers, they saw zoning as a way to protect the health and well-being of the upper and middle class by creating--through z oning--a decentralized, healthy, suburban environment. Health, safety, and welfare continue to be the legal basis for zoning today, which is the primary determinant of land use patterns in American cities. Modern zoning began in Germany as a way to control development and public health problems, but the German system never completely separated zoning into uses. When American planners adapted the system, they believed that not only should housing be separated from nonresidential development, but that residential di stricts should also be separated by housing type, such as single-family and multi-family units. In 1926, the Supreme Court in the Euclid v. Ambler Realty case decided in support of th e city ordinance that mandated districts that separated residential and industrial uses, stating that the city had the powe r to legislate for the health, safety, and welfare of its citizens. The Supreme Courts decision served to institutionalize zoning in the 1920s, and lay the foundation for low devel opment densities in the suburbs of American cities today (Frank et al., 2003; Schilling & Linton, 2005). Garden City Movement The appearance of the automobile, decline of the trolley lines, escalation of highway infrastructure, and government subsidized mortga ges pushed growth to the suburbs and vastly expanded metropolitan areas (Jackson, 2003). The Gard en City model, as an alternative to the suburban model, envisioned a number of small c ities separated by greenbelts and linked by intercity rail to carry goods and people. In 1902, Eben ezer Howard planned the physical layout of his garden city with institu tional buildings in the center, housing in the middle, and industry on the
36 outskirts. In 1923, the Regional Planning Associati on of America, which included some of the most influential people in American planning history, endorsed development based on the Garden City model. Although the members never built a true garden c ity, they applied the concept to several developments, including S unnyside Gardens in Queens and Radburn in New Jersey. In both developments, they substituted the gr id street pattern for a dendritic street pattern, placing great emphasis on the car, one of many ways that planners were helping facilitate the explosive growth of automobile use. The grid was seen as dange rous for pedestrians with so many crossings where every street was a throug h street. The Garden City Movement was an attempt to create an alternative to the standard suburb and create a healthy environment, but the solution helped to institutionalize the concept of the detached subdivision in American cities (Frank et al., 2003). In the 1960s, federal efforts to reso lve the urban crises of the 20th century included the National Commission on Urban Problems, the Presidents Commission on Urban Housing, Housing and Urban Development Act, Model Cities Program, and the Fair Housing Act (Frumkin et al., 2004). A century ago the le ading cause of death was infectious and communicable diseases. Today, the urban desi gn solutions to those problems are now contributing to the leading cause of death today--lifestyle habits that lead to chronic diseases (Frank et al., 2003). The long history of public health shows that the form of the built environment has clearly been a factor in health and disease in cities Lifestyle risks today, including physical inactivity, may be linked to the design characteristi cs of streets that affect the perception of walkability. Design of Walkable Streets The urban s pace--the street-is typically defi ned as the volumetric, three-dimensional void that is visually and or physic ally contained by buildings or the open area identifiable between
37 and around buildings (Orr, 1983). Ma ny streets are known by a singular quality that distinguishes them. A singular quality can be a special use or activity, or a characteristic spatial form and details, such as street furniture, lighting or planting patterns that create a visual and functional hierarchy (Lynch, 1960). These design features, which make up the vi sual character of the street and can be expressed as urban de sign qualities, are based on theori es and principles of design for public social spaces. But these design features have not been studied in detail or rated for significance for walkability (Southworth 2005). Studi es do show, however, that people are more likely to meet recommended levels of activity if they live on high qua lity and aesthetically pleasing streets with features such as a nice tree canopy, sidewalks, shops, windows on the ground floor, open green space, and varied architectur e with small-scale detail (Giles-Corti et al., 2003; Southworth, 2005; Zacharias, 2001). Urban Design Qualities for Public Spaces The literature on urban design supports the conc ept that urban design qualities are linked to the use of space and to physical features whic h create visual character or urban quality. The literature also describes how the features can be objectively measured and quantified. Important criteria used to measure visual character includ e: a defined area (the block face or facades of buildings in one block); an esta blished set of design features, such as windows, number of stories, roof shape, and materi als; and a critical frequency in which those design features are found on the building facades (Smith, 2003; Stamps 2000). The same criteria can be used to measure the character of an urban street as that street relates to walkability. However, the defined area includes the building facade on both sides of the street, the sidewalks or pedestrian path, and the street or cartpath.
38 An essential notion of visual character is the pa ttern that is created by the abstract features of buildings, such as the lines and edges of windows, walls, and roofs. People recognize and respond to the aesthetic message that is c onveyed by the pattern. Studies show common preferences for buildings based on small-scale ornamentation, material, color, and patterning (Smith, 2003). Another important concept for the design of walkable stre ets is that expert judgments and public preferences for the amount of detail are strongly correl ated. In studies that compared experts judgments with public impressi ons of how well buildings fit their context, the highest correlation was between the facade detailing followed by the height, shape, and complexity of the building (Stamps, 2000). The hi gh correlation of prefer ences has implications for the development of codes and the design of streets by professionals--if there is agreement on building detail, professionally designed st reets should appeal to the everyday user. Several urban design qualities are valued by users of urban spaces and presumed to be related to walkability: enclosure, transparency, human scale, complexity, and imageability (Ewing et al., 2005). Each of these distinct design qualities are defined or described by certain quantitative (measureable) design features that cr eate the quality. Literature from many fields, including architecture, landscape architecture, and envir onmental psychology, support the concept of urban design qualities as a method to de fine and describe walkable urban streets. The merits of each urban design quality are discussed in terms of the features associated with that quality and the relationship to walkability. Enclosure Enclosure refers to the degree to which the building walls, trees, and other vertical elements visually define the streets (Ewing et al., 2005). Spaces between buildings that also affect enclosure include the courtyards, plazas, and green spaces along the street. Enclosure is
39 often described as having the sense of an outdoor room or a space where the shape of the space is as strong as the shape of the buildings around it (Alexander et al., 1977; Cullen, 1961). Unwin (2003) described a space as the relationship betw een an object (in the ur ban context, usually a building) and the person who per ceives it. It is primarily determ ined by sight, but it can also be affected by smell, noise, and touch (tactile). Hu man orientation is strongly related to four horizontal directions: front, back, and sides. The enclosure of the two parallel walls and the long linear shape of the street control those four horiz ontal directions with fi xed boundaries that create a room-like sense of security, focus, and di rection (Jacobs, 1993; Un win, 2003). In the space between two pieces of architectur e an enclosing force works betw een the buildings that create the space. With increasing comp lexity of the building form (concave and convex forms), the exterior space becomes a stronger positive space (Ashihara, 1970). The height of the walls is crucial to the sens e of enclosure and orient ation. If walls are too low in relation to the width of the street, outward views are not contained enough to provide a sense of unifying space. Obtaining the right street wall height to width ratio is essential to defining the street (Hedman, 1984). Alexander et al. (1977) stated that the total width of the street, building to building, should not exceed the building heights. Hedman (1984) and Ashihara (1970) agreed that a 1:1 height-t o-width ratio gives a strong spatia l definition because the street wall height limits the sky view, almost complete ly containing the view. Jacobs (1993) suggested a 1:2 building height-t o-street width ratio. Streets have two problems with containing space. Because they do not have a roof or ends, the building walls must contain the space. To overcome this design problem, two conditions must be met: (a) A relatively uniform height of st reet space must exist to give the street crosssection strong unifying proportions and prevent wh at Hedman (1984) described as leakage of
40 space; and (b) the facades framing the street shou ld provide grips or snags in the form of facade details, texture, and materials to secure and hold the space in place. Architectural details, such as deep, large indentations, bold projections, and a rich textur e, help to hold and define the space. Orr (1985) also described texture on surfa ces as giving the impression of gripping the space. He explained that qualities of the text ure communicate the scale because of our past association with that texture. Complexity and rich detail, repeated from building to building (colors included), also influen ce shadow patterns which provide additional texture to hold the space (Hedman, 1984). Using a hierarchy of scaled features both vertically and horizontally provides a means for reading the building height if the features are a size with which most people are familiar (Hedman, 1984). Details such as belt courses an d cornices interrupt th e vertical flow and terminate facades to help define the space. The cornice suggests the presence of a horizontal plane--inferring a roof over the street. The silhouette s of roof lines also co ntain the space if they have a similar pitch and height (Hedman, 1984; Unwin, 2003). Parts of a building, such as major masses, percent of windows, bases or caps, and areas of different color, texture, or material, can also influence the scale of buildings and the sense of space (Orr, 1985; Smith, 2003). Many new urbanists advocate clos ing vistas at street ends with prominent buildings, monuments, or fountains to achieve enclosur e on all sides (Ewing et al., 2005). Jacobs (1993) stated that streets should have clearly marked end points to defi ne that area and serve as a reference point, and Curran (1983) noted that anot her dimension of streets, the length, can be manipulated with the use of curvilinear patter ns, bends and building projections to produce closure.
41 Street trees can also visually define a space with a ceiling of branch es and leaves that horizontally implies a ceiling, and they can suggest the vertical enclosure of an area with their trunks. The key to influencing enclosure with tr ees is the close spacing of the trees along the street (Arnold, 1993). Transparency Transparency is described as the degree to which people can see or perceive elements beyond the edge of a street, including the interior of buildi ngs. Features that influence transparency include trees, walls, windows, door s, fences, and midblock openings (Ewing et al., 2005). Transparency is most criti cal at the street level. The classic example is the display window in street level retail es tablishments where pedestrians can see into the building, as opposed to solid walls or reflective glass bu ildings (Ewing et al., 2005). Windows visually extend the interior out and allow the public to see the interior uses that make the street level more visually complex (Curran, 1983). Openings (doors) also extend and expand interi or spaces so that the interior and exterior have visual and functional overla p. Openings also provide informa tion that makes the experience on the street more meaningful by sending visual clues regarding uses, access, and linkage, whereas blank walls have the opposite effect (Curran, 1983; Jacobs, 1993). The proportions of windows, bays, and doorways to other features (the proportion of void to solid ), and variations in size and character of openings provide the cont rast between transparency and enclosure. Small trees can obstruct transparency by blocki ng views. However, large trees with high canopies create a partially transparent ceiling th at gives an awareness of space beyond, creating both transparency and en closure (Arnold, 1993).
42 Human Scale Ewing et al. (2005) described human scale as referring to a size or texture of physical elements that match the proportions and size of hu mans and relate to the slow speed at which humans walk. Human scale is important when walk ing close to buildings on a street because the person has a direct sense of the size of the building as it relates to human anthropometric measures (Orr, 1985). Visual elements such as st reet trees, pavement, architectural details, and street furniture contribute to human scale because they are typically features that people are familiar with in terms of size, for example, tables and chairs relate to the size of the human body. The range of human vision is a factor in the pe rception of street spa ce and scale. Our basic viewing orientation is aligned on the horizon in a close parallel to the ground. In this way, scale relates directly to our field of vision. When looking straight ahead, a person has approximately two-thirds of his view above the eye level plane which can affect the sense of scale in buildings (Orr, 1985). Urban designers differ on their defin ition of human scale with regard to the height and massing of buildings, finding anything from thr ee stories to six stories to be acceptable. Alexander et al. (1977) limited buildings to f our stories; while Lenna rd and Lennard (1995) found six stories to be acceptable. The width of the building also affects scale, particularly in proportion to the height. Building mass is primarily determined by the cr oss-sectional area of the building, followed by the amount of windows, and finally the amount of facade articulation or details (Ewing et al., 2005; Stamps, 1998). The presence of windows, the us e of horizontal or vertical partitions, the thickness of the vertical elements, and the overall proportion are all associated with less apparent mass (Stamps, 2000).
43 Perspective can also create the perception of human scale particularly with regard to perceived distance and effort to cover a distance. Perspective also has an effect on the spatial experience in street corridors. The visual distor tion on the linear edges of buildings links the buildings and produces a directi onal quality that directs people along the pathway (Curran, 1983; Orr 1985). Building features, such as arcades and awni ngs, give streets encl osure and human scale that support the commercial role s of the street. Seating adjacent to buildings and extended into spaces also gives a supportive transition zone fo r the main function of walking and provides human scale with furniture (Cur ran, 1983). Street trees can also affect human scale by creating a smaller space within the large sp ace of the street, particularly if the buildings are tall and the street wide. Arnold (1993) stated that trees are needed on streets which are more than 40 feet wide, to achieve human scale. Complexity Complexity refers to visual va riety in the physical environment. On the street complexity includes: architectural materials; color; ornamentation; diverse bu ilding shapes and sizes; various elements such as landscape plants, street fu rniture, and signage; and the movement and color from human activity (Ewing et al., 2005). Rapoport (1990) described complexity as the number of noticeable differences that a viewer obser ves in a defined time period, which relates complexity to speed of movement. Pedestrians re quire a high level of complexity to hold their interest. An environment has low levels of usab le information if elements are too few or too similar, if they are too predic table, or if they are too unorde red (Ewing et al., 2005). People enjoy areas with multiple levels of visual stimuli and scenes that can be re-examined (especially in a familiar area that they visit often). On a day-to-day basis, a degree of complexity will renew the
44 interest of the regular viewer but simplicity and order are also needed to facilitate comprehension of the larger composition by th e infrequent viewer (Hedman, 1984). Jacobs (1993) described the most popular streets as those cluttered with humans and life. Ewing et al. (2005) said that pedestrian activity adds to co mplexity. People are attracted to and feel safer around other people. Coherence (sometimes referred to as unity) can control complexity through the orderly arrangement of elements in the environment, giving a sense of visual order, for example, buildings that are similar, but not the same, in height and char acter (Jacobs, 1993). Coherence is achieved through consistent and complementary s cale, character, and arrangement of buildings, paving material, plant material, and street furniture (Ewing et al., 2005). Features of buildings that create visual coherence, particularly when repeated, include: the silhouette, material, color, surface detail, building scale, lo cation of entryways, proportion and placement of windows and doorways, and style of architectur e. The spacing between buildings and setbacks from the street also contribute to coheren ce (Groat, 1989; Hedman, 1984). Empirical studies on architectural details te nd to support the hypothesis that detail is an important part of preferences for buildings. E xperiments in which facades were created with varying degrees of silhouette complexity, facad e articulation, and surface detailing showed that the largest effects on preference were obtained by adding detail to the surface. Changes to the complexity of the silhouette were less importa nt, and facade articulati on was least influential (Groat, 1989; Stamps, 2000). However, the building silhoue tte is a distinctly important feature because the outline of the roof is critical to image recognition. Complexity in silhouettes can be determined from objective geometrical properties of the architectural shape, such as the number
45 of turns and angles in the sil houette that contribute to the pa ttern and complexity (Hedman, 1984; Stamps, 2000). Repetition and pattern can also contribute to complexity and coherence. Visual information, which occurs throughout the street at a relatively constant rate in a variety of building styles, creates a pattern that dominates randomness to become a whole. If a building does not relate to adjacent buildings, the cause is usually proportion and pattern inconsistency (Smith, 2003). Pattern is particul arly important because the mind creates order from complexity by subconsciously creating patterns from the varied elements (Nelessen, 1994). Hedman (1984) described how the spacing of bui ldings establishes a pattern and rhythm by the shadow lines of the spaces between the buildi ngs. Wide buildings lack rhythm and subtract from complexity, while narrow buildings in vari ous arrangements add to complexity (Jacobs & Appleyard, 1987). Nelessen (1994) explained that variations on basi c patterns can be created by varied building frontage through building orientat ion, set back lines, wi ndows, balconies, and lintels. Arnold (1993) explained th at landscaping, particularly shad e trees, are critical for a sense of visual coherence because buildings today lack complexity in their architecture. Burden (2006) described the benefits of street trees, including: [Street trees] convert streets, parking a nd walls into more aesthetically pleasing environments. There are few streetmaking elemen ts that do as much to soften wide, grey visual wastelands created by wide streets, parking lots and massive, but sometimes necessary, blank walls than trees. (p. 7) Jacobs (1993) referred to the complexity of the light and shadow patterns created by the branches and leaves of street trees on the wall s and sidewalks. He also mentioned the need for many different surfaces where light and shadow patterns are c onstantly moving. Signage and street furniture are also sources of complexit y. Most people prefer signage that is moderately complex, rath er than highly complex. Too much variation in location, shape,
46 color, direction, and lettering style creates chaos and confusi on for most viewers (Nasar, 1987). Street lights, fountains, benches, and public art all add to the mix of complexity, but some consistency in the style is preferred for a more unified and coherent look (Ewing et al., 2005). Imageability Imageability is the most important urban design quality for streets because it is influenced by other important urban design qua lities such as legibility, encl osure, human scale, linkage, complexity, and transparency. Imageability is refl ected in the combined ef fect of these qualities (Ewing et al., 2005). In The Image of the City Lynch (1960) gave a definition of imageability: That quality in a physical object which gives it a high probability of evoking a strong image in any given observer. It is that shape, color, or arrangement which facilitates the making of vividly identified, powerfully structured, highly useful mental images of the environment. (p. 9) Cullen (1961) related imageability to the use of a visual theme that creates a more cohesive sense of place by having all f eatures work together for a to tal impression and feeling of pleasantness. An important design quality associated with imageabil ity is legibility, which refers to the ability to navigate and unde rstand the spatial structure of a pl ace. Legibility is also related to linkage, another important concept related to imageability. Linkage refers to the visual and physical connections from space to space, building to building, and building to street that can occur longitudinally along a street or laterally across a street. Features that promote linkage include block length, pedest rian crossings, sight lines, sidewalk connections, and the use of continuous ro ws of street trees (E wing et al., 2005). Tree rows can psychologically connect ends of streets, and tree patterns, which reflect building form or geometry, can connect the buildin g to the street (Arnold, 1993). Building features that contribu te to the visual linkages and sense of unity include: window proportions, entryway placements, decorative el ements, materials, a nd silhouette (Hedman,
47 1984). Features such as entrance canopies and aw nings serve to extend and overlap the domains of public spaces and buildings. Building entrie s that are similar in proportion and character provide linkage and transition between these spaces (Curran, 1983; Hedman, 1984). Curran (1983) explained that ground treatment can also be a critical factor in the experience of the public area by explicitly ma rking areas devoted to movement. Patterns organize, link, and subdivide spaces and encour age movement by enhancing visual appeal and apparent distance. Rhythm and re petition in the pattern also help s discern distance and link areas. With curbs, material changes, and color patterns to indicate pe destrian zones, people are more likely to walk in clearly marked areas (Orr, 1985). Cullen (1961) showed that landmarks also co ntribute to image and a sense of place that inspires people to be in the space. These focal poi nts or landmarks, such as sculpture, public art, or towers of buildings, are termination points and spatial organizing a nd wayfinding devices, and they can be used for closure of long linear ar eas. They also give m eaning to a space through symbolism associated with events, values, and ideas that are important to the community (Curran, 1983). Two concepts are important for using the urban design qualities and associated physical features for developing walkable streets. One co ncept is the ability to define and measure the features and the other concept is the users percep tion of the value of the features for walkability. These concepts are formally studied as e nvironmental aesthetics or visual quality. Study of Environmental Aesthetics The study of the visual quality of the envir onm ent is important for designers to develop design standards and codes, and for policymaker s to establish design policy recommendations. Courts and legislatures also use study results to help enforce or create laws based on the visual quality of the environment (Ataov, 1998).
48 Despite conventional wisdom (i.e., beauty is in the eye of the beholder), research has confirmed common architectural preferences among the public that he lps to delineate a theoretical framework and definition for urba n design aesthetics (Ataov, 1998). Psychologists have described and operationalized this as aesthetic response, which is defined as favorable emotional appraisals or evalua tions of the environment (Ulric h, 1983). The aesthetic response results from the interaction betw een the user and the environment. It can vary with personality, expectations, and social and cu ltural experience, but commonalities occur across individuals (Nasar, 1994; Ulrich, 1983). The study of environmental aesthetics examines how the emotional response of people to the visual quality of the environm ent affects their spatial behaviors. The aesthetic qualities of the environment can evoke emotions and feelings such as pleasure, relaxation, excitement, and fear. People will act differently (their aesthetic response) based on fa vorable or unfavorable emotions about the environment (Ataov, 1998; Nasar, 1997). The relationship between building properties and aesthetic response is described as follows: The user has certain perceptions of bu ilding attributes. These perceptions lead to emotional reactions (affect) and judgments (cognition), which together lead to affective appraisals and connotative meanings, which in turn lead to aesthetic response and spatial behavior (Nasar, 1994; Ulrich, 1983). Measurable vs. Experiential Qualities Porteous (1996) explained that the degree of aesthetic respons e or delight that an urban dweller might experience depends on some basic aesthetic qualities and the artistic manipulation and coordination of those qualities. Researchers have shown that th e basic aesthetic qualities can be separated into two categories: the experi ential qualities and the physical qualities (Ataov,
49 1998; Lang, 1987; Porteous, 1996; Purcell, 1986). The physical qualitie s are the tangible, measurable qualities that collectively contribute to the intangible, experiential qualities that affect environmental preferences. Measurable phy sical qualities include formal design elements, such as scale, mass, pattern, proportion, line, form texture, rhythm, and color. The experiential qualities include the urban design qualities of im ageability, complexity, c oherence, transparency, and enclosure (Ataov, 1998; Kaplan & Kapla n, 1989; Lang, 1987; Porteous, 1996; Purcell, 1986). Human Response and Environmental Aesthetics Extensive research has been conducted on the relationship between environmental features and the way in which users respond to those features. Research has centered on three issues: (a) visual features and the perceptual and cognitive processes by which user s acquire, organize, and remember these features; (b) visual features a nd human reactions to them, such as emotional response and evaluation (affectiv e appraisal); and (c ) the connection between the two (Ataov, 1998; Downs & Stea, 1973; Lang, 1987; Moore, 1979; Nasar, 1997; Wa rd & Russell, 1981; Zube, Sell, & Taylor, 1982). Studies have attempted to identify and specify the design details and spatial configurations that contribute to qualities such as comple xity, coherence, and imageability. In addition studies have also tried to establish the relationship between the design details and spatial configurat ion and emotion, meaning, and the environment (Ataov 1998; Berlyne, 1971; Kaplan & Kaplan, 1 998; Lang, 1987; Wohlwill, 1976). Research Categories and Models Research categories and models have been de veloped to explain th e relationship between the responses of the user and the environmental features. While agreement exists on the models, different researchers divide them into different categories (Lang, 1987; Moor e, 1979; Zube et al.,
50 1982). Three of these categories a nd the models within them are pertinent to the study of the environmental design features of a walkable ur ban street: the Objective Relational Category, the Subjective Relational Category, and the Formal Aesthetics Category. Ataov (1998) offered these descriptio ns of the three categories. The Objective Relational category consists of models that focus on the objective analysis (measurement) of the environment and does not consider cognitive processing. These models deal with formal aesthetic features that translate into formats a pplied to design problems, such as guidelines. The Subjective Relational category emphasizes cogn itive processing and subjective meanings that people derive from the environment. The Formal Aesthetic category combines the models of the first two categories and is concerned with how th e structural aspects or patterns of the built environment affect peoples feelings rather than the purpose they serve or the meanings they provide. The models within each category are described below. Objective Relational Category The Objective Relational category has two m odels concerned with identifying aesthetic qualities or elements that can be measured or objectively presen ted (Appleton, 1975; Gibson, 1979; Ulrich, 1983). The first objective ecological model st resses design, and it explains how people perceive the environment in terms of formal artistic qualities, such as patterns and pattern contrast from line, form, colo r, and texture (Ataov, 1998). This model is important for the study of a wa lkable urban street when investigating the relationship between design features and the perceived purpose or walkablility of the street. For example, the details of architect ure which create line, form, textur e, proportions, rhythms, scale, and color make up the attributes of complexity and imageability in an environment. These attributes are related to percep tions and feelings, such as sati sfaction, pleasure, excitement, and
51 calmness (Ataov, 1998). Lang (1987) considered the features of the built environment that can be measured to include shapes, proportions, rhythms, scale, color, shadowing, and degree of complexity. The second objective ecological model generally focuses on the relationship between the physical attributes of an environment, the in formation gleaned (such as the purpose) from the attributes, and the emotional re action to them. These models a ssume that the value of an environment is inherent and external to the individual and can be perceived without cognitive processing (Appleton, 1975; Gibson, 1979; Ulrich, 1983). Subjective Relational Category The subjective ecological models are concerned with how the structural aspects or patterns, such as shapes, proportions, rhythms, scale, and color of the built environment, affect peoples feelings (particularly pleasure) rather than th e purpose they serve. The three most important models in the Subjective Relational category concentrate on how envi ronmental patterns or structures affect emotional appr aisals of the environment. The first model proposes that humans prefer environments that provide some advantage for survival, and it high lights the importance of availability of information through four ma in environmental components: complexity, coherence, legibility, and myst ery (Kaplan & Kaplan, 1998). The second model represents a subjective approach to understand ing environmental attributes a nd affective responses that are generally based on the assumption that affective responses occur after a learning process (Ataov, 1998). Ataov (1998) explained that an environment that fits existing knowledge is familiar, and while small differences to existing knowledge enha nce affinity and preference, large differences produce high levels of preference and increased interest. The third model assumes that peoples experiences, values, lifestyles, cultures, and subcultures may influence responses to the
52 environment, and through experience people lear n meanings that are associated with certain environments (Kaplan, Kaplan & Wendt, 1972; Lang, 1987; Nasar, 1997). The study of architectural pref erences, perceptions, and fee lings among the public helps to define urban design aesthetics and provides the ba sis for measurement of aesthetics. The ability to measure aesthetics based on public preferences is an important concept because it provides an empirical foundation for the use of aesthetic codes to control the appearance of the environment. Urban Design Standards and Codes The idea that preferences for physical design and aesthetic qualities can be quantified and measured suggests that codes and ordinances designed to control qua lity and aesthetics can enhance the quality of the built environmen t. Recent research has centered on the public appearance and functional f it of buildings. Research has also focused on the control of visual character for the public good through the use of design controls such as design guidelines, codes, and design review boards (Nasar, 1994; Ulrich, 1983). Designers, policymakers, and the public agree that controlling building a ppearance is important. More r ecently, the courts support this view, holding that aesthetics al one is an adequate basis for design controls (Nasar, 1994). Describing Physical Features in Design Standards and Codes Studies on the relationship between preference s and physical features can be used to generate architectural standards. However, a key concern is the ability to objectively measure the physical features. In Psychology and the Aesthetics of the Built Environment Stamps (2000) argued that the experience of different intensities of preference or pleasure in the built environment can be expressed as objective m easures in terms of materials and geometric relationships or locations in three-dimensional spaces. He discussed techniques that replace traditional descriptions to reduce the inherent vagueness in urban design standards. For example, the required frequency of a design feature in a specified area replac es the concepts of character
53 and visual richness. The required frequency can be expressed as the percentage of a facade covered by elements, making it easy to understand and implement the design principle. The notion of bulk is changed into th e concept of the amount of visual area as seen from a specified location. The concept of shape complexity is meas ured as the number of turns and angles in a silhouette. The objective measure of architectural deta il is possible because they are formed by materials which have dimensions and locations in three-dimensional spaces. Physical details can be described in terms of the materials, the loca tion, and/or any mathematical relationship (such as distance or proportion) that is defined among the locations (Van der Laan, 1983). This concept is particularly important for design codes that regulate the built form including architectural details and spatial dimensions, such as the Form-Based codes. Key Features of Aest hetic Design Codes Watson (2001) explained that aesthetic desi gn codes have certain key elements that distinguish them from other regu latory ordinances and zoning c odes. These codes include goals to capture peoples values, lifestyles, cultures, and preferences (a design charrette is used to develop goals), and writing and graphics (illus tration) that can be understood by the public including a definition of the design terms. Duerksen (1992) said that communities should: (a) inventory their resources and carefully identify what is worth protecting, preserving, and re plicating; (b) tailor the codes to fit their local situation; (c) develop explicit, detailed revi ew standards and define terms in measurable quantities such as height, bulk, materials, and roof pitch; (d) create a well qualified review board of experts and professionals that is supported by adequate staff re sources; (e) use visual aids and
54 illustrated guides to supplement the written review standards; and (f) integrate the codes with other planning goals and regulations. Aesthetic Codes and Walkable Streets The idea of codes and planning for aesthetics has gained some urgency as communities strive to make their towns more liveable and wa lkable. Several articles ha ve addressed the issue of architectural control through c odes and ordinances as a means to create more attractive and functional communities. And more recently, aes thetic codes have become prominent in communities that wish to create aesthetically pleasing, walkable communities and streets (Katz, 2004; Lewis, 2004). Many communities are moving be yond the concept of design gui delines to aesthetic codes as a legal tool to control the appearance and aesthetic value of new and infill development. The focus has turned from the question of the need for codes to how to develop, write, implement, and enforce codes that are often seen as subjec tive in nature. A new format for the writing of codes has emerged called Form-Based codes (FBCs). This format relies more on the measurable aspects of the urban environment that are rela ted to aesthetics and walkability (Watson, 2001). Design Codes for Walkable Urban Streets Urban design qualities have been presumed to be important to walkability. A recent study by Ewing et al. (2005) on the urban design qualities, which seem to have a significant relationship to walkability, has de fined features that can be m easured objectively. Because they can be measured objectively, these features can also be described and illustrated in written design codes which are then translated to the built form of the street. The urban street qualities investigated in th e study include imageabi lity, enclosure, human scale, transparency, and comple xity. The study led to the devel opment of an illustrated field manual for measuring urban design qualities re lated to walkability. The manual includes
55 instructions for rating an urba n street for walkability by qua ntitatively measuring certain elements related to the design qualities. Form al design principles, such as scale, mass, proportion, line, and texture, relate to the design qualities and are associated with the measurable physical features, such as building heights and widths, door and window placement, street and sidewalk widths, architectural detail, and stre et furniture detail (Cle mente et al., n.d.). The relationship between the desi gn qualities, the physical features of the street, the formal design principle that applies, and the applicable measurement is ad apted from Clemente et al. in the following list: Quality: Imageability o Street Features: courtyards, plazas, parks, landscape features, historic buildings, signs, outdoor dining, non-rectangular shaped buildings o Principle: scale, mass, line o Quantifiable Element: building shape-silhou ette, occurrence of courtyards, plazas, parks, signs, dining, landscape feat ures per linear unit of street Quality: Enclosure o Street Features: distance of sight lines proportion of continuous street wall (building faade), visible sky, awnings, bu ilding height, street trees, street lights o Principle: scale, mass, proportion, line o Quantifiable Element: wall height and widt h in relation to street/sidewalk width, street tree and pedestrian light height, awning/ove rhead height and depth Quality: Human Scale o Street Features: buildings, articulatio n of building details, windows, doors, building height, planters, street furniture, street trees, sight lines, street width, sidewalk width o Principle: scale, mass, proportion, line, texture o Quantifiable Element: building height, percent pavement texture, street tree height, window, door and wall percentages, proportions and hei ghts, furniture and planter percentages and dimensions Quality: Transparency o Street Features: windows, doors, street wall, mid-block passages o Principle: proportion, line o Quantifiable Element: proportion of windows to street wall, number of doors visible, occurrence per liner unit of windows, doors, and passages
56 Quality: Complexity o Street Features: number of buildings, building projections, dominant and accent colors, window detail, building and pavi ng materials, building setbacks, outdoor dining, public art o Principle: scale, mass, proportion, line, texture o Quantifiable Element: percentage of colo rs, building projections, door visibility, Building age, window proportions/ mullions percentage of building and paving materials, depth of setbacks and occurr ence/linear unit of dining and public art The concept that quantifiable features are associated with design qualities related to walkability is particularly important for aesthe tic codes, such as Form-Based codes. These aesthetic codes regulate the form or look of a community or street with the goal of making that street or community more walkable. Form-Based Codes The term Form-Based codes is a relatively new term for codes that are based on form rather than use. Although the term is new, th e concept has been around for a while under various names, such as performance zoning and district -based zoning (Lewis, 200 4). The approach was first applied in Seaside, a ne w urbanism community in Florid as Panhandle, about 20 years ago by Duany, Plater-Zyberk & Company (DPZ), a planning firm from Miami. The DPZ firm continued to refine and adapt the method for a ne w planned unit development, The Kentlands, in Gaithersburg, Maryland, and ultimately for more than 200 new and existing communities (Katz, 2004; Lewis, 2004). Petaluma, California, was the fi rst city in the nation to formally write and adopt Form-Based codes in 2003 and Columbia Pike, in Arlington County Virginia, recently adopted FBCs specifically to support a pe destrian-oriented development (Katz 2004). The concept and structure of FBCs origin ated from SmartCodes, a template that was derived from Smart Growth principles devel oped by DPZ and licensed by the Municipal Code Corporation in Tallahassee, Fl orida (Katz, 2004). The Californi a State Assembly recently passed
57 Assembly Bill 1268, which specifically enables the practice of Form-Based development regulation in California, and th e Assembly has endorsed Form-Bas ed codes in its general plan guidelines, referring to Form-Based codes as a useful implementation measure for achieving certain general plan goals, such as walkable neighborhoods and mixed-use and transit-oriented development (Katz, 2004, p. 21). Katz (2004) explained that wh ile conventional zoning controls land use and density, FBCs emphasize form and scale of the street and public realm, regulating the form of the built environment. The intent of the code is to create a predictable public realm by controlling physical form through city or county regulati ons. Instead of form following function, it is function following form, which allows for multiple uses for one space. The form, the buildings, and the configuration of the street remain th e same, but the use changes over time. Although the use is regulated in most codes, it is secondary to the regulation of the built form (Katz, 2004; Pierce, 2003). The code regulates the form of the buildings including items such as the porch, stoops, colonnades, awnings, balconies or bay windows, and shop-front windows. The configuration (the spatial definition) of the street and sidewalk is also regulated by the code. The intent is to be prescriptive and enable a predictable and stable physical environment (Katz, 2004). The codes start with a community visioning pr ocess to develop a consensus vision which is conveyed through illustrative graphics. Physical characteristics of buildings are typically summarized as standards that es tablish maximum and minimum building heights, placement of structures in relation to fronti ng streets, building elements such as doors, windows, and porches, and configuration of spaces such as entrances, parking, yards, and courtyards. Codes may also
58 include standards for a range of street types and additional architectural standards for more control over the appearance of build ings (Katz, 2004; Pierce, 2003). Important concepts of FBCs include: achieving a more predictable built result; emphasizing building form and typology; encouraging public participatio n; motivating multiple property owners to develop independently yet op erate within a communally agreed-upon vision; promoting mixed-use; advocating infill that is comp atible with existing structures; creating short, concise, visual, and readable codes that are ea sy for citizens to unders tand; and requiring less oversight by review boards. The primary purpos e is shaping a high qual ity, community centered, walkable public realm, particularly in the de sign of public buildings, streetscapes, and public squares (Katz, 2004; Lewis, 2004). Summary While research has shown a relationship betw een physical activity and health, no study has shown a direct relationship between physical activity, physical hea lth, and characteristics of the built enviro nment. The built environment seemi ngly influences utilitarian physical activity (commute by foot) through proximity of destinations, linkage of pa th network, quality of the path context, and availability of motorized transport. Urban sprawl is often linked to poor health because the characteristics of sprawl, such as dist ance to destinations and connectivity of streets, appear to negatively impact the ability to be physically active. Other environmental determinants of walki ng include weather, topography, safety, and aesthetics. The least stud ied of these elements is aesthetics. Little is known about the effects of the street level design features or the relative importance of th e visual details and landscape features on the desirability of places for walking. Some of the factors that contribute to the aesthetic design qualities of th e street include building design, landscaping, paving materials, street trees and street furn iture, signage, and lighting.
59 Studies have examined how the emotional re sponse of people to the visual quality (aesthetics) of the environment affects their behaviors. But effo rts to measure the effects of particular street level features for walkability have been difficult due to difficulties with the objective measurement and quantifying of th e features. The objective measurement of architectural detail seems to be the most promis ing because the details and elements are formed by materials which have dimensions and lo cations in three-dimensional spaces. A recent study by Ewing et al. (2005) looked at urban design qualities that are presumed to be related to walkability including: imageability, enclosure, human scale, transparency, and complexity. Each of these qualitie s is linked with certain built feat ures in the environment that can be counted and objectively measured. The idea that physical design and aesthetic qualities can be measured is an important concept related to codes and ordinances designed to control quality and aesthetics. Form-Bas ed codes, a new type of code based on form and aesthetics, rather than use, is currently being used to shape a walkable public realm by regulating the physical form of public buildings, streetscapes, and public squares.
60 CHAPTER 3 MATERIALS AND METHODS Information Sources and Assessment Tools Data for m y study were collected from severa l different sources in three phases. Phase I was an audit of urban streets where development of the street was regulated through the use of Form-Based codes. Phase I also included an audi t of historic urban stre ets recognized for being walkable. Phase II was an interview survey of users (business owners) who had businesses on the audited streets. Phase III was a review and summary of regulated features in written Form-Based codes from 30 communities. The urban design quality (UDQ) models and the perceptual quality sc ore sheet that were used as research tools in my study were obtained from a recent report and field manual prepared by Reid Ewing and colleagues for the Active Li ving Research Program of the Robert Wood Johnson Foundation. Field Manual and Score Sheet (Audit Instrument) The field manual and score sheet were prepared by a team of researchers: Otto Clemente and Reid Ewing from the University of Maryland, Susan Handy and Emily Winston from the University of California at Davis, and Russ Br ownson from Saint Louis University. The field manual, Measuring Urban Design Qualitie s: An Illustrated Field Manual (Clemente et al., n.d.) includes an illustrated guide and score sheet. The field manual and score sheet were developed as an audit instrument to describe and quantify se veral key urban design qua lities that appear to have a relationship to walkability and also ha ve the potential to be measured objectively (Clemente et al., n.d.). The conceptual fram ework and methodology for developing the field manual and score sheet were described by the authors in a final report titled Identifying and Measuring Urban Design Qualities Rela ted to Walkability, Final Report (Ewing et al., 2005).
61 The primary motivation was to develop a test instrument to be used for additional research to assess the urban design qualities that have the greatest potential to describe or explain the design features of a walkable urban street. A s hort summary of the methodology is as follows: recruit an expert panel develop a list of perceptual urban desi gn qualities through lite rature review determine if they are related to walkability develop a list of features (physical characteristics) through literature review and expert opinion link them to one or more of the ur ban design qualities (model building) determine if they could be objectivel y measured (validate the features) develop an audit instrument using the va lidated urban design quality models The Ewing team developed operational definitions and measurement protocols for eight urban design qualities derived from the literatu re. The team then listed 106 small-scale design features hypothesized to have a relationship to walkability. Thes e features were linked to the eight urban design qualities to de velop urban design quality (UDQ) models. Nineteen of the 106 hypothesized features were validated by the Ewi ng team as having a statistically significant relationship to walkability. The UDQ models with validated feat ures--transparency, enclosure, human scale, complexity, and imageability--were used to create the score sheet, which is the audit instrument for this study. Throughout my study, reference will be made to two sets of design features: hypothesized features that were validated a nd used in the audit are referred to as validated features; hypothesized features that were no t validated and not used in the audit are referred to as nonvalidated features. The differe nce between the features is an important distinction, because my study considers validated and non-validated features separately in both the review of the codes and the user interviews. The score sheet from the Clemente et al.s (n.d.) Field Manual is simply referred to as the audit.
62 Phase I: Walkable Street Surveys Ten communities were s elected for site visits to evaluate a street usi ng the audit. Five of the 10 communities were chosen from 30 communitie s that had written and used Form-Based codes for development. The other five were chosen from a list of communities in California with historic streets that have been designated as walkable. Fourt een streets (seven historic and seven FBC streets) within the 10 communities were selected for the audit. Selecting Communities for Survey The Form-Based code communities were selected primarily on the extent of implementation of the FBCs since they were formally adopted by the community. Most of the Form-Based codes were written between 2002 an d 2007 and they were so recently adopted by the communities that no design or construc tion had been implemented. The level of implementation in each community was determ ined by contacting the planning department by telephone. Only those communities that had new construction (based on the FBC) on a minimum of one block of a street or corridor were considered for a site visit. The seven walkable communities with historic downtown streets were chosen from a list of walkable California communities developed by Walkable Communities Inc., a nationally recognized organization established by Dan Burd en. Burden is a well-regarded expert and consultant in walkable community design who ha s worked in more than 1,200 communities in North America (retrieved April 3, 2006, http://www.walkable.org/article6.htm ). In addition to the comm unity being designated walkable, they were also required to have a historic downtown street that was recognized for its walkability. The other consideration for all 10 commun ities was the location. After considering California and Florida as potential study areas, the San Francisco Bay area presented the most possibilities for case studies in the smallest ge ographic area. The communities were chosen for
63 their proximity so that certain environmenta l conditions, such as weather and vegetation (landscape plants and street trees), would be similar for the communities. The communities were also selected for similar demographics, popul ation size, and land size. A map of the San Francisco Bay area (Figure 3-1) shows the geogr aphic location of the cities. The 10 communities included: Mountain View Petaluma Livermore Gilroy Hercules Palo Alto Healdsburg Santa Cruz Los Gatos Cotati Two of the FBC communities, Livermore and Gilroy, had two different types of FormBased code streets. The street s were either all new constr uction, including buildings and streetscape, or streets that had maintained the historic buildings but significantly redesigned the street. Two audits were done in each city, one for each of the different FBC streets. Mountain View had one historic street th at had been extended through the use of codes which was audited as two separate streets; an hist oric street and a FBC street. Peta luma had both historic streets and streets built from Form-Based codes. The commun ities with historic downtown streets and FBC streets used for the audit included: Historic Streets o Mountain View o Petaluma o Cotati o Palo Alto o Healdsburg o Santa Cruz o Los Gatos
64 Form-Based Code Streets o Mountain View o Petaluma o Livermore: new street o Livermore: new streetscape o Gilroy: new street o Gilroy: new streetscape o Hercules A segment of street was evaluated in each community using the audit and following the procedure outlined in the Clemente et al. (n.d.) field manual. Each audit took approximately two to three hours, and included recording counts a nd percentages and photo-documenting the street environment. Every effort was made to evaluate each street at approximately the same time of day during the course of two weeks Photos were taken at locations that best illustrated the urban design qualities that were on the audit. The photos included in the field manual were used as guides or examples of the types of scenes to be photographed. No prot ocol was developed for taking photos as they were not in tended to be used for audit purposes, and they appear in the study only for illustration. The recorded counts and percentages were co nverted to numerical scores for each of the urban design quality mode ls using the protocol (multipliers and constant) on the score sheet (each score is the average fo r a one block length). A score for each of the urban design qualities--imageability, enclosure, human scale, transparency, and complexity-were recorded on each audit score sheet. The scores correspond to the explanatory potential of that UDQ model for a walkable urban street. In other words, the highest score represents the urban design quality that best e xplains or describes the features that make that particular urban street a walkable, pedestri an-oriented environment. Phase II: User Interview The second step of data collection w as an in terview with seven merchants/business owners who have businesses along two streets that were audited in Phase I. The purpose of the interview
65 was to solicit their opinions, as users of the street about features they belie ve create a pedestrianoriented street. The features they cited were compared with the validated and non-validated features and the features regulated in the FBCs. A matrix of the hypothesized (validated and non-validated) features was adapted from Ewing et al. (2005) Identifying and Measuring Urban Design Qualities Related to Walkability, Final Report (Appendix 4, p. 68) for use in Phases II and III. The matrix was used as a tool to screen and record the types of physical features cited by the inte rviewees and regulated in the design standards of each of the 30 Fo rm-Based codes. As stated, the UDQ Final Report listed 106 hypothesized features; however, the matrix fo r this study was reduced to 76 of the 106 hypothesized features. Because codes are a descrip tion of the regulated built elements, only those features associated with the built elements were retained for the matrix. Features that concern pedestrians and vehicular traffic ( non-built elements), such as numb er of pedestrians, number of people seated, and noise level, we re eliminated in the matrix. Interview Questions The urban design quality models in the audit were used to develop the interview. The description of each of the five different UDQ models (transpare ncy, enclosure, human scale, complexity, and imageability) was us ed to generate two or three questions designed to help the participant think about and describe the different physical features th at make the street walkable. Petaluma was chosen as the site for the interv iews because the city was an early adopter of FBCs (2003), and the city has the greatest number of blocks built from the FBCs. The city also has a thriving downtown historic district with several walkable streets. One of each type of street, historic (Kentucky Street) and FBC (2nd Street), was audited and used for the interviews.
66 Potential interviewees were located by accessing the Petaluma Downtown Association website ( http://www.petalumadowntown.com ), which includes a list of retail m erchants in Petaluma with their address and phone numbe r. The executive director of the Downtown Association was contacted by phone and e-mail to di scuss the reason for selecting Petaluma as a case study, the intent of the study, and the need fo r volunteer participants. The director sent an introductory e-mail describing the study to th e business owners who are members of the association. This step was followed by a pers onal phone call to 13 merc hants with businesses located either on Kentucky Street (historic) or 2nd Street (FBC street). Eight of the business owners agreed to be interviewed. Interview time s and dates were arranged, and the participants were interviewed over a period of two days. A tota l of seven people were interviewed (two were interviewed at the same time and the eighth participan t was unable to interview due to a fire in an adjacent business), for a total of six transcripts. Each interview lasted approximately 45 to 60 minutes and the interviews took place either at their bus iness or at an eating establishment on the same street as their shop. The interviews were recorded using an Olympus VN-4100/VN4100PC Digital Voice Recorder and transferred to a PC for transcription using the Olympus Digital Wave Player software program. The opening statements of the interview informed the participants that the interview questions would require them to think about what they observe as they walk down the sidewalk, and then offer their opinion about what they see and experience. They were told that the street refers to the space from building front to buildin g front, which includes the building facade, the sidewalks, the road, and all features between th e buildings. They were also informed that the survey concentrates on the visual aspects of th e street environment and how what they observe
67 might affect how they feel while walking on the sidewalk. In other words, what do they see as they look down the street that makes them want to walk down the sidewalk and be on the street? All features cited by the participants were reco rded and a list of the features listed in the Clemente et al. (n.d.) UDQ Final Report was used to analyze the comments of the interviewees. The list was used to determine which features c ited by the users matched the features regulated in the FBCs and the features on the audit. The comments were also reviewed to determine the features cited most often by the users and they were compared with the results from Phases I and III. Selected comments from the participants were used throughout the discu ssion to illustrate the value of the different UDQ models from the perspective of the user. The qualitative assessment by the users is important to the di scussion of the use of FBCs to develop walkable urban streets. Their comments help determine the number and type of built features that should be regulated in the codes to create a stre et that will be used. Phase III: Form-Based Codes Assessment The Form -Based codes used in the assessment (Table 3-1) were downloaded from official city websites. Codes are genera lly listed under several different names, such as Form-Based codes, Specific Plans, Precise Plans, Downtown Development Plans, or Di strict Master Plans. The plans typically have the Form-Based codes embedded as a chapter in the plan. All FormBased codes include a regulating plan, buildi ng form standards, and public space/street standards. Some codes also include a set of architectural standards and a set of landscape standards. The codes used in this study were requ ired to meet several criteria and there were two limiting factors: (a) availability of the code s--Form-Based coding is a relatively new code concept and a limited number of communities have used Form-Based codes; and (b) Because this study focused on small-scale urban details, all codes chosen for review had to include architectural standards. A few of the codes that were reviewed were in the first public draft
68 format. Although they are complete, it is possible that subsequent revisions or addendums could alter the codes. The state of California and de sign firms in California have been the most progressive in the writing and use of Form-Based codes; therefore, 23 of the 30 codes reviewed for the study are from communities in California. The communities vary somewhat in demographics and size, but they are generally mid-size to small communities located on the periphery of large cities. Each Form-Based code was screened using the hypothesized (validated and non-validated) feature matrix to determine the number and type of built features regulated in the codes. Several data sets were produced: (a) the number and percent of codes in which each feature was regulated; (b) the average number a nd percent of validated audit features regulated in each code; and (c) the average number and percent of non-validated features regulated in each code. Figure 3-1. Map of surveyed communities.
69 Table 3-1. Form-Based Code s: city, state and title City, State Code Title Arlington, VA Arlington/Columbia Pike FBC Azusa, CA Monrovia Nursery Specific Plan (residential) Benicia, CA Downtown Mixed Use Master Plan Benicia, CA Lower Arsenal Specific Plan Bloomington IL Brentwood, CA Burlingame, CA Form-Based Code, Section 44.6-26 Downtown Specific Plan North Burlingame/Rollins Area Specific Plan Cape Coral, FL Cotati, CA Cape Coral Downtown Master Plan Downtown Specific Plan Farmers Branch, TX Fort Bragg, CA Form-Based Code: Station Area (TOD) City of Fort Bragg Design Guidelines Gilroy, CA Downtown Gilroy Specific Plan Hercules, CA Central Hercules Plan Livermore, CA Downtown Specific Plan Montclair, CA North Montclair Downtown Specific Plan Mountain View, CA Pasadena, CA Downtown Specific Plan Central District Specific Plan Paso Robles, CA The Olsen/Beechwood Specific Plan Petaluma, CA Pleasant Hill, CA Redwood City, CA Riverside, CA Central Petaluma Specific Plan Pleasant Hill BART Station (TOD) Downtown Precise Plan Downtown Specific Plan San Luis Obispo Margarita Area Specific Plan (TOD) Santa Clarita, CA Downtown Newhall Specific Plan Santa Rosa, CA Downtown St ation Area Specific Plan Ventura, CA Downtown Specific Plan Whittier, CA Uptown Whittier Specific Plan Winter Springs, FL Town Center District Code Woodford County, KT The New Urban Code for Woodford County (residential)
70 CHAPTER 4 RESULTS Data Collection The inten t of the Phase I audit of the historic walkable streets was to provide an initial stratification of the urban design qualities to create a framework on which to organize and investigate the research questi on. The audit of the FBC streets was then conducted to compare the stratification of the UDQ mode ls of FBC streets to the stra tification of the UDQ models of the historic streets. This comparison served two purposes: (a) to determin e if the streets shared similar urban design features and qua lities, and if they did, (b) to determine if the features of the UDQ models of the audit provided a reasonable fr amework for studying the pot ential of FBCs to create walkable streets. A comparison of the audit scores (Table 4-1) showed the same stra tification of the UDQ models for the FBC streets and the historic street s. This similarity suggests that the codes are regulating the same features found on historic walkable streets, which implies that FBCs have the potential to create walkable streets comparable to historic walkable streets. To further investigate the potential of the codes, the Ph ase II interviews were conducted to learn which features the user perceives to be meaningful for a walkable street versus the feat ures regulated by the codes. The premise is that if the features of value to the user are regulated in the codes, the codes have the potential to create a walkable stre et from the perspective of the everyday user. To determine if the typical FBC regulates the features present on the FBC streets (in other words, were the features of the built street a result of the codes), a review of 30 codes was completed in Phase III. The assertion is that if the features are regulated in the code they will appear on the street, and application of the codes will have successfully creat ed a walkable street.
71 The results for Phase I are presented as a stratification of the UDQs based on the audit scores. The results for Phases II and III are pres ented in two categories: validated features and non-validated features. The rationale for separatin g the features was to allow a comparison with the audit UDQ models from Phase I, wh ich include only validated features. Phase I: Walkable Street Surveys Audit results from both the historic street s and the FBC streets demonstrate a similar stratification with the models, ordered as follows--from high to low scores: imageability, complexity, human scale, enclosure, and tr ansparency (Table 4-1). The scores, taken individually, have no status; they were simp ly compared and stratified among themselves. For both streets, the features of the UDQ model of imageability had either the highest percent or largest quantity, or both, of features on the street, giving the imageability model greater explanatory power to describe a walkable urban street. The parallel stratification of the UDQ models for both types of street s suggests that the streets are at least similar in the validated UDQ features in the audit. Phase II: User Interview The initial review of the in terview transcripts was conducte d to sim ply tally the total number of features cited by the participants in response to the interview questions (Table 4-2). All features that the participants cited were counted, regardless of whether the feature is on the original list of hypothesized (va lidated and non-validated) features from the Ewing et al. (2005) Final Report General trends, which were apparent in the comments of at least 50% of the participants, included features associated with the building faade, such as historic styles, building height, colors, architectural details, awnings, signage, windows, and window displays. Comments also included features in the sidewa lk, such as sidewalk width, be nches, street trees, planters,
72 pedestrian lights, tables, a nd chairs. Other comments were more function-oriented with maintenance, type of shops, and type of parking all in the top 50%. All comments made by all of the participants totaled 51 different features In addition to commenting on physical features, many of the interview participants spoke of the streets in terms that described their feelings about the streets. Some of the descri ptive terms included: comfortable, unique, warm, inviting, eclectic, relaxed, interesting, contained, diverse, complex, charming, having character, pleasing to the eye, lacking in uniformity, cohesive, old school, old fashioned, and cozy. Validated and Non-validated Features Cited by Interview Participants The list of features cited by the participants was then compared to the validated and nonvalidated features. The primary purpose was to show which of the validated and non-validated features were cited most often by the interview pa rticipants (Table 4-3). The data were used to develop a stratification of the UDQ models that could be compared to the models from the audit in Phase I and the models from the code review in Phase III (Table 4-4). If the model stratification--based on th e features important to the users--is the same as the model stratification derived from the codes, then some agreement ex ists between the codes a nd the users. The codes should therefore have a high potential to create a walkable street from the users perspective. The stratification of the models from the inte rviews does not resemble the stratum of the models from the code review in Phase III (Table 4-5). The lack of similarity indicates that the interview participants are not ci ting many of the features regulate d in the codes, and implies that the codes may not have a high potentia l to create a street that the users would consider walkable. The potential of the FBCs to create a walkable street based on the user s perspective appears weak because they do not regulate the highest percentage of features in the models that are most important from the users perspective.
73 The stratification of the models from the user interviews is more similar to the stratum of the audit models from Phase I (Table 4-6). This m eans that the users preference for features is a close match with the features that are present on the historic and FBC streets. A close match seems logical because the streets in the audit were those used da ily by the interviewees, so it is likely they would comment on the features they see every day on the streets. The stratification of the user m odels also makes sense when the features with in each model are considered from a users perspective. Both the complexity and imageability models have specific features that are much more likely to be noticed and used by the average user, such as building colors, awnings, doors, signs, courtyards street furniture, ou tdoor dining, and parked cars. It is therefore likely that these featur es are remembered and commented on by the users. The features in the enclosure and transparency models are not as likely to be mentioned by the typical user because many are not typically in the common vocabulary of the lay person, such as street wall, enclosed sides or terminated vista. Also, the user may be aw are of certain features, but might not mention it in his comments because he does not associate it with the street. For example, when considering the audit feature of proportion of sky ahead, the user may be very aware that he sees sky ahead, but it is not a part of his perc eption of the street. Phase III: Form-Based Codes Assessment The Form -Based codes were screened to determine the number and percent of validated and non-validated features regulated in an average FBC. A matrix with a list of the features and the 30 codes was used to record the features regulated in the codes. Validated audit features regulated in Form-Based codes The first review of the FBCs considered only the validated features from the matrix. The number and percent of codes that regulate validated features are s hown in Table 4-7. For example, building height is the most regulated va lidated feature, appearing in 29 out of 30 (96%)
74 of the codes. Table 4-7 was developed to determ ine if the validated features are regulated with high frequency in the codes. If they are regulated with high fre quency, the probability that the application of the codes will create a walkable st reet may be higher. If not, the possibility that other factors are responsible for creating a walkable street must be considered. The tally of the validated features was also us ed to compare the stratif ication of the models from the FBC review with the stratification of the models from the street audit in Phase I. To develop the stratification, the percent of validat ed features regulated in the codes for each particular model was used (Table 4-8) to determ ine the position of that model in the stratum. A code stratum similar to the audit stratum would lend more support to the idea that the codes are regulating the same features that appear on the historic streets. The stratification of the models (Table 4-9) from the FBCs does not resemble the stratification of the models from the street audits which implies that the features regulated in the codes are not the same as the features in the a udit models. For example, the codes regulate only an average of 2.5 (28%) of the 9 validated feat ures from the imageability audit model, yet all nine features are accounted for in the audit of the FBC street s. The discrepancy between the number of features regulated and the number present on the FBC st reet presents the question of how features, which are not regulated in the code s, appear on the street s designed by application of the codes. One likely answer is that the featur es are regulated in the co des, but in a different form or language than the language of the aud it. Therefore, when reviewing the codes the features were not read or translated directly as an audit feature. The c odes are often written to regulate many specific features or details, wherea s the audit features are often more broad in description. For example, a code may not specif ically regulate a long si ght line, which is an audit feature in the enclosure model. But a code will regulate many different features, such as
75 street trees, building height, and st reet width that create long sight lines in the built environment. This means that long sight line wa s recorded as present on the FBC street in the audit, but not directly regulated in the codes, implying that other regulated fe atures may be creating enclosure features on the street. Another possibility is that the features on the street are th e result of other guidelines and standards. It is also possible the features might have been added to the design by the architect or designer, based on their interpretation of the code, or, they were simply installed by the builders or owners of th e buildings along the street. Since the codes regulate many more features than those in the audit, it was speculated that using the validated features only in the code review may not be an adequate method to determine the model stratification for the codes. Therefore, the non-validated features were considered in the second review with the matrix. The possibility was considered that combinations of the nonvalidated and validated features regulated in the codes may be cr eating what is recorded as an audit feature on the FBC streets. Validated plus non-validated features regulated in the Form-Based codes The FBCs were then screened to determ ine which of the non-validated hypothesized features were regulated most often in the FBCs (Table 4-10). The co mbined numbers of the validated and non-validated features were used to create a new st ratification of the models. This new stratification was, as before compared with the stratificati on of the models in the street audit (Table 4-11). Again, the stratification of the models deri ved from the FBCs does not resemble the stratification of the models from the street audi t (Table 4-12), with th e exception of the human scale model. The addition of the non-validated features made little difference in the order of the models. The FBCs are on average re gulating the smallest percent of features in the models with
76 the highest score in the street audit, and the largest pe rcent of features in the models with the lowest score in the street audit. Based on the difference in the model stratifica tion, the potential of th e FBCs to create a walkable street appears lacking because the FBCs do not regulate the same percent of features, both validated and non-validated, in each of the audit models. However, it is likely that the discrepancy in the model stratific ation continues to be due to a difference in the format and language of the codes and the audit. Summary The results highligh t some of the difficu lties in measuring, quantifying, and describing urban design qualities and features that make up a walkable street No similarity was found in the stratification of the FBC models when compared to the audit or interview models. Based on the lack of similarity, the potential of the FBCs to create a walkable street appears lacking because they do not regulate the same percent of features as the audit models or the same features cited by the users. Although the stratificati on of the models from the code review does not show a strong pattern (model order) that would clearly indicate that the F BCs have the potential for creating walkable streets, the comparison of the stratifi cation of the models doe s present the opportunity to discuss the relationship of the features in the models to the f eatures in the codes, the use of models to evaluate walkable streets, and the va lue of different features for creating a walkable street. No final conclusion can be drawn about which models would have th e greatest influence on the potential of FBCs to create walkable streets. But the stratification of the audit and user models could be used as a guide to the most impo rtant models and type of features to regulate in the codes.
77 The codes do regulate a high total number of the features: on average 38 of the 76 validated and non-validated features (50%) are regulated in 50 % of the codes, and every feature is regulated in at least one or more of the codes. It may therefore be more useful to consider the total number of features, along w ith the percent in each UDQ model, to determine the potential of the codes. Certain design features began to em erge as key features based on the audit scores, the frequency with which they ar e regulated in the FBCs, and the frequency with which they are cited by interview participants. These key features may be important to consider for additional features on an audit for walkable streets. Tables 4-1 to 4-12 Table 4-1. Average audit scores in ea ch UDQ for Historic and FBC Streets Table 4-2. Number and percent of design features cited by interview participants Participants Design features 6100% Common architectural style (historic buildings), Building colors, Active uses 583% Benches, Street trees, Memorable architecture (architectural details), Awnings 466% Maintenance, Distinctive signage Building signs, Type of shops 350% Small planters, Pedestrian lights, Common building height, Tables, Chairs, First floor windows, Window displays, Type of park ing, Courtyards, Sidewalk width 233% Outdoor dining, Mid-block passage, Misce llaneous street furniture/items (trash cans, banners railings, umbrellas) Overhangs, Street width, One-way street, Building projections (wall angles, grooves, fla t/blank walls), Tree in wells (grates), Plants/landscaping, Long sight lines, Number of people, Vistas/views, Textured street (paving materials), Textured sidewalk (cobblestones/pavers/decking), Landscape features (waterfront/river), Various building ages (new buildings), Directional signage, Moving cars/speed, Midblock crossings, Parks, Clear area in sidewalk 117% Public art, Concrete street, Recessed doors, Anchors on ends of streets, Terminated vista, Angled corners, Building materi als, Loading zones, Curb extensions UDQ models Average scores for Historic Streets Average scores for FBC Streets Imageability 5.23 5.03 Complexity 4.37 4.50 Human Scale 4.26 4.13 Enclosure 3.05 2.89 Transparency 2.76 2.86
78 Table 4-3. Number and percent of participants who cited validated and non-validated features Participants Features 6100% Percent of historic building fronts, Do minant building colors, Accent building colors, Proportion of active uses, Common architectural style, % of historic building fronts 583% Miscellaneous street items, Memorable architecture, Common tree spacing/type, Trees in wells, Awnings/overhangs, Other street furniture 466% Buildings with identifiers, Place/building/business signs, Distinctive signage, Common signage 350% Building height, First floor facade with windows, Small planters, Pedestrian scale street lights, Courtyards, Tables, Seats, Parked cars, Sidewalk width 233% Long sight lines, Outdoor dining, Parks, Directional signage, Midblock passageways, Street width, Building projections, Various building ages, Sidewalk clear width, Textured sidewalk, Number of paving materials, Moving cars/speed, Midblock crossings, Trees in wells/landscaped beds, Large planters without trees, Landscape features 1-17% Public art, Visible recessed doors, % of Sky across/ahead, Common building heights, Terminated vista, Number of primary building materials, Curb extensions, Textured street, Building height to street width ratio Table 4-4. Percent validated and non-validate d features cited by participants Table 4-5. Stratification of FBC and interview models FBC models Interview models Transparency Imageability Enclosure Complexity Human Scale Human Scale Complexity Transparency Imageability Enclosure UDQ Models Number of validated and non-validated features Total number of validated and nonvalidated features % of validated and non-validated Imageability 11 15 73% Complexity 26 40 65% Human Scale Transparency 21 8 35 14 60% 57% Enclosure 8 17 47%
79 Table 4-6. Stratification of audit and interview models Street Audit Models Interview Models Imageability Imageability Complexity Complexity Human Scale Human Scale Enclosure Transparency Transparency Enclosure Table 4-7. Number and percent of FBCs that regulate validated features Number and % Validated Feature 2996% 2790% 2583% 2480% 2377% 2273% 1963% 1860% 1757% 1653% 1550% 1343% 930% 827% 620% 517% 26% Building height % Buildings with non-rectangular silhouette, First floor facade with windows Entire facade with windows Percent of street wall Visible sets of doors, Common building heights Common tree spacing/type Memorable architecture Pedestrian scale street lights Buildings with identifiers, Visible recessed doors, Common window proportions Place/building/business signs Plazas, Parks, Dominant building colors, Accent building colors Courtyards, Number of buildings Percent of historic building fronts, Street connections to elsewhere Public art Small planters, Outdoor dining, Miscellaneous street items, Terminated Vista, Long sight lines, Proportion of active uses % of Sky across/ahead, Number of buildings with non-rectangular silhouette Table 4-8. Average percent of validated features regulated in each FBC Table 4-9. Stratification of audit and FBC models (validated features) UDQ models Average number of validated features/code Total number of validated features Average % of validated features Transparency 1.8 4 45% Human Scale 2.4 6 40% Enclosure 1.0 3 33% Complexity 1.9 6 32% Imageability 2.5 9 28% UDQ Models from Audit UDQ Models from FBCs Imageability Transparency Complexity Human Scale Human Scale Enclosure Enclosure Complexity Transparency Imageability
80 Table 4-10. Number and percent of FBCs th at regulate non-validated features Number and % Non-validated features 2683% Parked cars, Awnings/overhangs 2583% Common materials 2480% Arcade, Enclosed sides, Number of land uses 2377% Common setbacks, Building projections 2273% Sidewalk width, Average building setback 2170% Number of primary building materials, Street width 2067% Trees in wells/landscaped beds 1963% Height interruptions, Buffer width 1860% Distinctive signage, Common building masses 1757% Number of trees 1653% Common architectural style, Curb extensions 1447% Median width, Other street furniture 1240% Moving cyclists (bike lanes), Midblock passageways, Landscaped median 1137% Various building ages, Sidewalk clear width 1033% Textured sidewalk, Large planters without trees 930% Building height to width ratio, Number of paving materials 723% Textured street 620% Seats 517% Common signage, Proportion sidewalk shaded 413% Landmarks, Moving cars/speed (speed limits), Mid-block crossings 310% Directional signage 27% Tables 13% Traffic signs, Building height to str eet width ratio, Number of landscape elements, Overhead utilities, Landscape features Table 4-11. Average percent of validated and non-validated features regulated in each FBC UDQ Models Average number of validated and nonvalidated features Total number of validated and nonvalidated features Average % of validated and non-validated features Transparency 10.1 14 72% Enclosure 11.2 17 66% Human Scale 15 35 43% Complexity 15.2 40 38% Imageability 5.7 15 38% Table 4-12. Stratification of A udit and FBC Models (validated and non-validated features) Audit models FBC models Imageability Transparency Complexity Enclosure Human Scale Human Scale Enclosure Complexity Transparency Imageability
81 CHAPTER 5 DISCUSSION Urban Design Quality Models and Form-Based Codes The discussion concentrates on the relationshi p of the UDQ models of the audit to the features that are regulated in the cod es and cite d by the users. Three conc epts are speculative or tentative in nature, and the intent of the discussion is to demonstrate how and why these concepts are proposed. The first concept states: A high total number of regulated features in the codes will increase the probability that combinations of those features will produce the desired audit features on the built street. The second concept st ates: A high total number of regulated features that are the same features cited by the users will increase the potential of the codes to create a walkable street preferred by the users. The thir d concept states: A greater percent of regulated features associated with the imageability, comple xity, and human scale models will increase the potential of the code to create a walkable ur ban street. The discussi on will consider the UDQ models of imageability, complexity, human scale, enclosure, and transparency. The discussion will also examine the results of the street audit, the perceptions and preferences of the users, the code review, and the expert opinions from the literature review. Form-Based Codes Format Frequent reference is made in the discussion to the Pasadena Central District Specific Plan, 2004 (City of Pasadena, Planning and Developmen t Department, retrieved April 10, 2006, from http://www.ci.pasadena.ca.us/planning/deptorg/co mmplng/GenPlan/centdis.asp ) when describing the relationship of an urban design quality or de sign feature to the code s. The Pasadena plan regulated 57 out of the 76 validated and non-va lidated features, the second highest of the 30 codes reviewed. The Pasadena pl an is also the most comprehe nsive of the FBCs reviewed. A unique aspect of the plan is the format of th e design guidelines. The guidelines describe 15 urban
82 design concepts/qualities, explain the intent for each (often describing the desired experience), and give recommendations for implementing the f eatures related to that quality. Many of the qualities and concepts are the same or similar to the UDQs that were considered in the Ewing et al. 2005 study, and the format (urban quality, plus intent, plus features) is very similar to the organizational approach of the audit. The format makes it simple for the person using the code to link each feature to a design qual ity and understand the design intent and benefits of the features to the user. The discussion also makes frequent reference to the FBCs for Gilroy and Livermore, two cities included in the street au dit. These cities consistently scored highe st in most of the UDQ models in the audit and among the 30 codes re viewed. They regulated a high number of validated and non-validated features. The Gilroy codes (Downtown Gilroy Specific Plan, 2005, City of Gilroy, retrieved April 12, 2006, from http://www.ci.gilroy.ca.us/planning/projects.html ) regulated 63 out of 76 fe atures, and the Liverm ore codes (Livermore Downtown Specific Plan, 2004, City of Livermore, retrieved April 23, 2006, http://www.ci.livermore.ca.us/dsp/dsp.html ) regulated 53 out of 76 fe atures. All the c odes on average regulated only 34 features. Perceptions of Users and Experts The perceptions and preferences of the us ers (business owners) are presented through comments from the interview participants from the Downtown Petaluma Business Association. The interview responses refer to Kentucky Street a historic street in downtown Petaluma, and 2nd Street, an FBC street also in downtown Peta luma. The views of the experts are expressed by including relevant citations for the literature review.
83 Discussion Format The discussion is organized to review each UDQ model in the following manner: Audit features in the FBCs: A comparison of th e audit features and regulated code features is the basis for explaining why the scores of the FBC streets were similar to the scores of the historic streets even though the codes did not regulate many of the audit features. The comparison is also the basis for explaining th e concept of the importa nce of the UDQs of imageability, complexity and human scale. Regulated features in the FBCs: All the featur es regulated in the codes that link to the UDQ models are listed to demonstrate how features regulated in the code could collectively create and be recognized and reco rded as an audit feature on the built street. This exercise illustrates the c oncept that a high number of features regulated in the codes may be important. Proposed features for a street audit: This portion of the discussion proposes new features that are not currently in the UDQ audit mode l. The proposals are put forth based on the frequency of regulation in the codes a nd frequency of comments by the users. Expert and user perspectives: Includes inte rview comments and literature citations to illustrate the concept of how regulated features link to features cited by the users, which may increase the potential of the codes to create a street preferred by users. Imageability Model The UDQ model for im ageability was found to have the strongest explanatory or descriptive power (highest audit score) in the 14 street surv eys. Ewing et al. (2005) wrote that imageability is the most important quality to stre et design because it is influenced by the other urban design qualities of legibility, enclos ure, human scale, linkage, complexity, and transparency, and it is reflected in the compos ite effect of those qualities. Imageability is described by Ewing et al. (2005): Imageability is the quality of a place that makes it distinct, recognizable, and memorable. A place has high imageability when specific physical elements and their arrangement capture attention, evoke feelings, and create a lasting impression. (Appendix 2, p. 40) Many of the reviewed codes also seek to descri be and create high imageability as stated in their goals and objectives. For example, one of the primary goals for the Downtown Gilroy Specific Plan (City of Gilroy, 2005) stat es: Downtown Gilroy will showcase restored historic
84 buildings, attractive new buildings, a bustling tr ansit center, new housi ng, pedestrian-oriented public spaces and amenities, and a new town plaza (p. 21). Several references in the literature review agree that the qu ality of being memorable is important. Jacobs (1993) stated that the best streets are those that leave a lasting, st rong impression and are easy to remember. Audit Features for Imageability in the FBCs The Phase I audit included six features, lis ted below, for imageability (adapted from: Measuring Urban Design Qualities Related to Walkability: An Illustrated Field Manual Measuring Urban Design Qualities Scoring Sheet, Clemente et al ., n.d.). Two original features number of people and noise on the street was not used for my audit because they are not design features that can be implemented by the codes. Number of courtyards, plazas, and pa rks (both sides, within study area) Number of major landscape features (both sides, within study area) Proportion of historic bui lding frontage (both sides, within study area) Number of buildings with identifier s (both sides, within study area) Number of buildings with non-rectangular shapes (both sides, within study area) Presence of outdoor dining (your side, within study area) The audit features for imageability were not regulated in high numbers in the codes. On average, only 2.5 out of a total of nine (28%) of the validated features in the imageability model are regulated in the FBCs. The number and percen t of codes that regulate each imageability feature are shown as follows: 17 (57%) Number of Buildings with identifiers 15 (50%) Plazas, parks 13 (43%) Courtyards 9 (30%) Proportion of historic building fronts 6 (20%) Outdoor dining 2 (6%) Number of buildings with non-rectangular shapes 1 (3%) Number of major Landscape features The imageability model in the audit had a highe r average score on the historic streets than the FBC streets, with three out of the top five highest scores for imageability on the historic
85 streets. This is not an unexpect ed result as the features for imag eability are much more likely to be found in greater numbers on a historic street, particularly the proporti on of historic building fronts and number of buildings with non-rectangular shapes. Th e FBC streets in Livermore, Gilroy, and Hercules also scored high in imageability. The codes for two of these communities, Livermore and Gilroy, regulate a high number of imageability features, with five out of the six audit features for Gilroy and four out of the six audit features in the Livermore codes. However, the codes for Hercules regulate only two out of the six audit features in th e codes, yet it scored high in the audit. Several examples might help explain why code s, such as those for Hercules, that do not specifically regulate a high number of imageabil ity audit features would produce streets that score high in imageability. One example is the a udit feature of number of buildings with nonrectangular silhouettes. Typically, a large number of this type of buildin g can be found on FBC streets. Although the codes do not specify a non-re ctangular silhouette, ma ny of them do regulate a great number of architectural details and architectural styles th at create a non-rectangular shape when built. Also, many of the streets have existin g historic buildings from the 1850s to the 1950s that more typically have an irregular shaped facade. Another example is number of buildings with identifiers. The codes do not generally specify how many bu ildings must have identifiers (signs), but most of them do have detailed si gn regulations, stating size, type, materials, and location, that translate in the built environment to signs on nearly all buildings. These examples demonstrate how a collection of details or features re gulated in a code can produce the audit feature on the built street. These examples also show how a design or architectural term in a code, such as parapet or cornice, can be interprete d in different ways and result in the feature bein g present on the street and recorded on the audit.
86 Regulated FBC Features Related to Imageability Features regulated in the FBCs are linked with an audit feature from the imageability model (in bold) to demonstrate how regulated feat ures can indirectly cr eate features (and UDQs) on the FBC streets. For example, the codes ma y not specifically state that major landscape features be present on the street, but they might regulate features, such as a landscaped median, raised planters, or minimum size of planters which would be recognized as a major landscape feature and recorded in the audit. Plazas, parks, courtyards may be regulated in the code through: open public space, fountains, garden walls, fences, courtyard en trances, uses for public space, and landmarks. Number of major landscape features may be regulated in the codes through: landscaped medians, plant materials, raised planters minimum footprints for planters, minimum number of trees in a public space, plant size, and terminated vistas. Percent of historic building fronts may be regulated in the codes through: renovate or reconstruct historic buildings, use common architectural style, details on historic buildings, preserving architectural heritage, and landmarks. Number of buildings with identifiers may be regulated in th e codes through: types, materials, and locations for signs, logos and shapes for wayfinding signs, building signs, and distinctive signage. Number of Buildings with non rectangular shape may be regulated in the codes through: historic buildings, common architectural style, landmarks, roof lines, building projections, and upper story setbacks. Outdoor dining may be regulated in the codes as: a list of permitted uses (restaurants and cafes), colonnades, arcades, front porches, street furniture, and tables and seats. Proposed Audit Features for Imageability Two additional features also frequently regulated in the codes-but not represented in any of the existing audit models-are proposed to be in cluded in a street audit. The regulated features are linked with a proposed audit feature (in bo ld) to show how the codes support adding these features to an audit. One important issue to re member throughout the discussion of the features
87 for UDQs is the ability to measure a particular feat ure in a quantitative form, such as a count or a percentage. Any new feature that is proposed for a model must meet th is criterion to be useful in an audit instrument for walkable street features The audit item must be written to indicate how the feature will be counted or measured. Memorable Architecture : Regulated features such as awnings and overheads, marquees and balconies, front porches, colonnades and arcades, stoops and doors, bay windows, light fixtures, facade composition, detailing, and ornamental relief should be counted in the audit as number of buildings with f acade detail and decorations. Quality Building Materials: Regulated features such as wood, stone, brick, tile, transparent glass, plaster, painted signs, cloth/canvas awni ngs, metal balconies, exposed rafters and beams, moldings, metal downspout s and scuppers should be counted in the audit as number of buildings with quality materials. Memorable architecture is proposed as an a udit feature--separate from non-rectangular buildings and historic archit ecture --because 63% of the codes specifically regulate architectural details that create memorable architecture and 83% of the interview participants cited architecture is being memorable. The literatu re also supports memorable architecture as an important quality of walkable streets. By coun ting buildings with facad e detail and decoration, both memorable new buildings and historic buildings can be recorded in the audit. High quality construction material is also a proposed a udit feature because ma ny codes emphasize the importance of quality materials and several of the interview participants commented on new, versus old, materials. Expert and User Perspectives The literature and user perceptions support ma ny of the imageability features as being important to walkability. The merit of each a udit feature is discussed, including relevant comments from the users and citations from the literature review.
88 Historic Buildings and Buildings with Non-rectangular Shapes Thirty percent of the codes regulate historic building fronts as an im portant visual quality. All the interview participants cited historic buildi ngs as important features in the street. One code example is the Pasadena Central District Specific Plan (City of Pasadena, 2004), the District Wide Guidelines for Community Character incl ude Guideline CC 5: Recycle Existing Buildings and Landscapes. The intent of the guideline is described as follows: Existing buildings and landscape elements provide a sens e of historical and physical c ontinuity, strengthen the urban fabric, and reinforce the unique qualities of the Central Dist rict (p. 133). The Pasadena city-wide desi gn criterion includes cultura l expression, noting that a community should express local history and cultu re. Recommendations include: (a) encouraging the recycling of historic or ar chitecturally significant downtown buildings; (b) maintaining the distinguishing qualities and features of historical or architectural ly significant buildings; and (c) repairing and retaining original building materials when feasible. The literature also supports the not ion that architecture is importa nt to identity or sense of place. Unwin (2003) in Analysing Architecture, declared that the fundamental motivation of architecture is to identify places (p. 15), and Stamps (2000) wrote that sense of place (visual character) can be defined by the design featur es, such as building materials, windows on the building facade, number of floors, and the roof form of buildings. The users agreed. When asked what captures peoples attention most on the historic streets, one interview participant replied, Its got to be the old buildings. I think thats neat. You definite ly notice when you have left the old and you are in the new. When asked specifically about buildings, one par ticipant noted that the little details of the historic buildings on Kentucky Street were impor tant, Theres a lot of metal detail on this
89 building. It was poorly painted, but it still looks nice. Another partic ipant said, The ornate trim and sorta the, you know, the moldings and the ging erbread aspect. Anothe r participant noted the historic architecture (Figure 51A) and the variety of colors and different shops, commenting, Its unique and exciting but I wish we had mo re plants. We need more planters and lights on trees. One participant stated, The se buildings here [on 2nd Street] are absolutely gorgeous and they fit within, I mean, they are new, but th ey have that kinda old look, you know, the oldfashioned look. Another particip ant commented on the same stre et, Its clean, and neat, and new and interesting, I think they did a great job architecturally on everything (Figure 5-1B). However, the same participant, when asked if there was anything about the look of the building that encouraged people to walk answered, No, I dont think so. But she noted that on other memorable streets history played a role, saying, Theres some history here [on 2nd Street] but they didnt do a very good job here because they could have done a lot of things. They could have done plaques, just simple things, or put it in the sidewalk, that makes it interesting to people. Ewing et al. (2005) and Jacobs (1993) both noted that imageab ility is the quality of a place that makes it memorable and leaves a la sting impression. One participant noted that 2nd Street would not make a lasting impr ession on anyone right now, saying: I think it has to grow into it. I think it has the right start bu t it needs more time. Kentucky Street is better because it has the old architectural buildings, here [2nd Street] you can still tell its a developers building. Over time it will probably change. I definitely see the difference between the two streets. Courtyards, Plazas, and Parks Courtyards, plazas, and parks are considered as one feature in the audit, and nearly half the interview participants mentioned them in their comments. One interview participant noted that what captured her attention most was the congr egation of people in the small courtyard on
90 Kentucky Street, saying, People ma ke it inviting there. Another participant referred to the small courtyard as a breezeway and noted that many people stopped to use the benches and chat (Figure 5-1C). Fountains are often found in courtyards, and ma ny of the codes recommend them for added character and imageability. The attr action of moving water, both visual and aural, is universal and water encourages passive engagement with the environment for relaxation (Carr, Francis, Rivlin, & Stone, 1992; Marcus & Francis, 1990). One interview participant from 2nd Street commented on the courtyard and fountain several times (Figure 5-1D), noting the congregation of people between the two buildin gs: We have people who come w ith their kids and strollers. The fountain that we have out there, if you come on Saturday or Sunday afternoon, youll see lots of people congregating around it; theres no cars; its more intimate [feels closed in] and comfortable [in the courtyard]. Number of Buildings with Identifiers Distinctive signage and number of buildings with identifiers are regulated in 57% or more of the codes. Distinctive signage is an element that can contribute to the imageability of a street by adding interest. Rapoport (1990) st ated that pedestrians require a high level of complexity to hold their interest, noting that elements that hold interest include signs, building details, changing light patterns, and people. Sixtysix percent of the interview part icipants cited buildings with identifiers as important to a walkable street (Figure 5-2A). Several of the participants who mentioned signage considered it to be a component of the building facade. One interview participant from the new FBC street (2nd Street) noted that signs make a difference: Ever since I put my blade signs up, Ive had my I cant find you calls go down 80%. It works, it stands out, its a different co lor, mines a different shape, it makes a big
91 difference, it really does. One participant comme nted on the signage on th e historic street as having the same shape and same bracket that hol ds it to the building, yet still appears unique. Nasar (1987) wrote that most pe ople prefer signage that is m oderately complex, although too much variation in location, shape, color, dire ction, and lettering style can create chaos. Several of the codes include standards for wayfinding elemen ts such as a coordinated system of signs and maps to be included in th e street scape. One participant had this comment about the signage on the FBC street: Its huge [very important], the signage there is really bad, theyre still working on it, its just horrible. The signage was an afterthought and that should be primary. Theres no signage [directional signage] at all, even in the parking structure. There should be a sign that says, You are here. Another participant from the historic street complained that the pedestrian signs in the new FBC district were not placed to encourage peopl e to walk this way [to the historic streets]. Major Landscape Features, Terminated Vistas, and Landmarks Terminated vistas and landmark s are design elements often incorporated at the street ends to achieve enclosure. Ewing et al. (2005) noted that these elements are typically prominent buildings, large monuments, or fountains of a very distinct design th at contribute to the imageability of the street. Jacobs (1993) wrote that most great streets have a special feature to mark the beginning and end. These reference poi nts, when well designed, contribute in a significant way to great streets. In Petaluma, 2nd Street has a small view of the riverfront (Figure 5-2B), and a terminating historic building, but only one interview participant commented on the river saying, We do have a lot of foot traffic in this direction, I think it s because of the river walk. They redid the whole river and made that a ll cobblestone. I think th at really helped people want to walk over there. Kentucky Street has a terminating view of a wonderful park on a hill, but none of the participants commented on the pa rk. However, one participant commented on the
92 multi-level Victorian buildings that anchored the ends of the streets and were considered as landmarks. Curran (1983) noted that landmarks, su ch as towers of buildings, are termination points and spatial organizing and wayfinding devise s. These types of landmarks can be used for closure of long linear areas. Fi gure 5-2C shows the use of a tower on Railroad Avenue, an FBC street in Hercules. Outdoor Dining Outdoor dining appears under both imageability and complexity on the audit. The literature typically links outdoor dining more with comple xity. However, when asked about memorable streets, one participant commented on the outdoor restaurant seating: One of the things that is most memorable to me is the, down there on the end of 2nd Street, is the wood deck. Its a very visual thing wh en you see 20 chairs out there and tables. It makes it pop out, you know, umbrellas, the same thing. Some of the participants remarked on streets in other familiar towns and how pleasant they were, having a wide strip of sidewalk with tables, chairs, and umbrellas. The FBC street surveyed in Mountain View (Figure 5-2D) is an example of a street that specifically had outdoor dining regulated in the codes. Memorable Architecture (B uildings with Facade Detail and Decoration) Memorable architecture is a proposed audit f eature important to imageability which is also proposed for the human scale model. Citations from the literature and comments from the users make an argument for including memorable arch itecture as an audit feature. Smith (2003) discussed the qualities of architecture, such as decoration, ma terials, and morphology that create the synergy or memorable quality of a public spa ce to encourage pedestrians. He explained that the details are important to the visual character and aesthetics, which is important to walkability, because streets are architecture plus space and time. Southworth (2005) stated that varied architecture with small-scale de tail contributes to explorability and changing vistas, which are
93 important attributes to the context of the street. Hedman (1984) noted that building features, such as window proportions, entry placement, decorative elements, style, materials, and silhouette, contribute to a sense of unity and visual linka ge. One interview participant agreed, commenting that the shape of the windows is important, particularly bay windows (Figure 5-3A). Other features of memorable architecture re gulated in the codes include building form, such as classical proportioning and symmetrical facades, and architectural details, such as colonnades, columns, arches, piers, and ornament al detailing. When asked how buildings helped create walkable streets, one interview participant noted: It feels comfortable when you can see things that are coming off the building, like even in architecture where they have on the bottom, in stead of a plain straight column, they put a border around them. I think that really adds a lot to it, instead of just having a flat building that has no depth. Quality Construction Materials The second proposed audit feature for imageabil ity is quality construction materials. Many of the codes regulated the t ype and quality of building materi als, noting that the buildings should be viewed as a long-term civic investment. An example comes from The Pasadena Central District Specific Plan (City of Pasadena, 2004), District Wide Guidelines for Building Design, Guideline BD 6 which stated: Encourage High Quality Construction. The intent of the guideline is described as follows: It is imperative that all buildings are cons tructed as a long-term addition to the urban fabric. A well-built structure adds value to the Central District. It co ntributes to the stock of well-crafted buildings, and communicates the significance and endur ing quality of the place. (p. 157) Recommendations include employi ng durable and high quality ma terials, particularly at the street level, and encouraging materials th at show permanence and quality, such as stone, terra-cotta, tile, metal, brick, and transparent glass. It is also recommende d to design architectural features as an integral part of the building rath er than those that appear to be tacked-on or
94 artificially thin. One interview participant spoke about the quality of materials used on the new theater facade (Figure 5-3B) visi ble from 2nd Street: They put this old art deco style out front, and if they had just spent that same money on something hand painted, something a little less plastic, it would have had more charm. Stamps (2000) explained that details are related to preferences for buildings, with e xperts and the public in high ag reement over facade details, such as the carvings shown in Figure 5-3C. One pa rticipant noted the difference between the new architecture on the FBC street and the ol d architecture of th e historic street: On Kentucky Street they look different, lik e different buildings. You can look at the bottom and say, this building is recessed in, it has tiles, the next one is all glass, and the next one, which is part of it, is stone, a nd you have three totally different looks in one building. On the bottom level you do not see that here [on 2nd Street]. They tried to do it here. We have a different look to some degree because our awnings are different color, and the buildings change color. The bottom looks th e same. The upper part they tried to change by a little bit different architecture. We have a different window set-up. They get credit for attempting to do that. One interview participant did not think there wa s anything in particular about the buildings on the FBC street that encouraged people to walk, except to note: I ts pretty, its clean, its new. All thats very obvious and the deve loper that owns these buildings, they are the best in town at maintaining the properties. Summary In summary, on average the codes do not direct ly regulate a high number of audit features for imageability. However, they do regulate many other architectural details and landscape features that, when present on th e built street, result in the feat ures on the audit for imageability. Those codes that did regulate a high number of features relate d to imageability also had high scores on the audit. Many of th e hypothesized non-validated featur es in the imageability model, which were not included in the audit, such as terminated vistas, landmarks, and distinctive signage, can be linked to the validated audit feat ures. For example distinctive signage is often
95 found on the buildings on the street and is counted in the audit as a build ing with identifiers. Two features proposed to be included as new a udit features are memorable architecture and quality construction materials. Memorable arch itecture is proposed so that new buildings and historic buildings, which contribut e to the visual quality, are reco rded in the audit score. The feature of quality construction materials also makes it possible to include new buildings in the assessment of the visual quality. Many regulated features in the c odes link with and result in the audit features for imageability being present on th e street, which suggests that the FBCs have a high potential to create a walkable urba n street based on the imageability model. Complexity Model The UDQ model of complexity had the second highest descriptive pow er for a walkable urban street in the street surve y. Ewing et al. (2005) wrote that com plexity depends on variety, and they described complexity as follows: Complexity refers to visual richness of a place.depends on the variety of the physical environment, specifically the numbers and kinds of buildings, archit ectural diversity and ornamentation, landscape elements, street furniture, signage, and human activity. (Appendix 2, p. 45) Audit Features for Complexity in the FBCs The Phase I audit included five features listed for complexity (adapted from: Measuring Urban Design Qualities Related to Walk ability: An Illustrated Field Manual Measuring Urban Design Qualities Scoring Sheet, Clemente et al., n.d.). One original feature, number of people, was not used in the audit because it is not a desi gn feature that can be implemented or affected by the codes. The five features are as follows: Number of buildings (both sides, within study area) Number of basic building colors (both sides, within study area) Number of accent colors (bot h sides, within study area) Presence of outdoor dining (bot h sides, within study area) Number of pieces of public art (both sides, within study area)
96 The audit features for complexity were not re gulated in high numbers in the codes. Only building colors is regulated in 15 (50%) of the codes, and out door dining is regulated in six codes. On average, 1.9 complexity features out of 6 ( 32%) are regulated in each code. The number and percent of codes that regulate each complexity features are shown below. 15 (50%) Dominant building colors, accent building colors 13 (43%) Number of buildings 8 (27%) Public art 6 (20%) Outdoor dining The complexity model scored high in the audit of the FBC streets. Thr ee out of the top five highest scores for complexity were on streets built from Form-Based codes. Again, FBC streets in Livermore, Hercules, and Gilroy scored high in this model. The codes for two of these communities, Livermore and Gilroy, regulate a high number of complexity features, with three out of five features for Gilroy a nd five out of five features for Livermore (as compared to the average of 1.9 out of 6 features regulated). Th e codes for Hercules do not regulate any of the audit features for complexity. Because the FBCs for Livermore regulate all five of the audit features, it would be reasonable to expect those features to be present on the street, resulting in a high score on the audit. A high score on the audit fo r Gilroy is also reasonab le with three of five features regulated. FBCs for Hercules regulate n one of the features, yet Hercules also scored high in number of buildings and number of ba sic and accent building colors (Figure 5-4A). However, an explanation exists for this par ticular discrepancy. The building colors were regulated through a different enti ty, Community Development and Public Services (CDPS), and were not included in the FBCs. The total number of buildings was also not included in the codes, however, minimum (16 feet) and maximum (160 feet) building widths were regulated, which indirectly influences the number of buildings per block face. The buildings averaged 45 feet in width, resulting in a high
97 number of buildings in the audit count. This particular feature was common for all the codes, which typically emphasized narrow building widths and discouraged buildings with long facades and no architectural division. Outdoor dining was also not regulated in the Hercules codes; however, each building had a small entry courtyard with two or three small tables and a few planters, which made a very inviting outdoor space. The buildings were not fu lly occupied by the intended businesses at the time of the audit (some were still realtor offi ces). But the occupants of the buildings were observed eating their lunch and meeting with clients in the courty ards (Figure 5-4B). Regulated FBC Features Related to Complexity The features related to complexity, which ar e regulated in the FBCs are linked with the audit features (in bold) to show how they indi rectly create the audit features in the built environment, and are recognized and recorded as audit features. For example, many codes do not specifically regulate outdoor dining, but they regulate street fu rniture that can be used for outdoor dining. Number of buildings may be regulated in the code through: maximum and minimum building widths, space between buildings, distance between doors, pattern of building openings, architectural style, scale and mass to match existi ng buildings, building type, and building proportions. Number of building colors may be regulated in the code through: building materials, in keeping with existing colors, and style of architecture (historic colors). Outdoor dining may be regulated in the code through: permitted uses (restaurants and cafes), colonnades, arcades, front porches, type of street furniture, tables, and seats. Number of pieces of public art may be regulated in the co des through: gateway features, artisan crafted architectural details, landmarks, decorative utilities, street furniture, pavement markings, planters, environmental graphics, ornate stre et lights, fountains, murals, banners, mosaics, and window displays.
98 Proposed Audit Features for Complexity Three non-validated complexity features, bu ilding projections, paving materials, and parked cars, are proposed as audi t features based on how frequently they were regulated in the codes and cited by interview part icipants. Parked cars were regul ated in 83% of the codes and cited by 50% of the users; buildi ng projections appeared in 77% of the codes and were cited by 33% of the users; and paving mate rials were in 30% of the codes and were cited by 33% of the users. The proposed features are listed w ith a qualitative descri ption for an audit. Building Projections/Faade Patterns : Regulated features such as awnings and overhangs, marquees and balconies, front porches light fixtures, colonnades and arcades, stoops and doors, and bay windows should be co unted in the audit as number of building projections. Paving materials : Regulated features such as textured sidewalk, text ured street, and clear pedestrian passage should be counted in the audit as number of different paving materials. Parking : Regulated features such as parking structures, parallel parking, diagonal parking, and parking bay types and dimensions should be counted in the audit as percent of street with parked cars or parking bays. Expert and User Perspectives The literature supports the value of complexity for a walkable urban street. Hedman (1984) stated that for the everyday user, a degree of comp lexity will renew his interest, but simplicity is also needed for comprehension of the larger space. Ashihara ( 1970) noted that with increasing complexity of the building form, the exterior space becomes a stronger positive space, and Rapoport (1990) remarked that pedestrians require a high level of complexity which he described as the number of noticeable differences the vi ewer observes in a defined time period. Rapoport further stated that complexity includes such feat ures as building details, people, surfaces, signs, and changing light patterns.
99 Number of Buildings None of the 30 codes reviewed specified a se t number of buildings per block, as block lengths vary in different communities. But n early every code did regulate maximum and minimum building widths, which translate to a maximum and minimum number of buildings per length of block. The literature generally supports the concept of many sm aller buildings on the ground floor for interest and complexity. Hedman (1984) stated that the spacing of buildings establishes a pattern and rhythm by the shadow lines between bu ildings, with narrow buildings generating an irregular but definite rhythm a nd wide buildings lacki ng rhythm. Figure 5-4C shows the pattern of buildings in Hercules with approximately a 45 foot width for each building. Building Colors Stamps (2000) explained that small-scale ornamentation, su ch as material, color, and patterning, adds the element of visual texture a nd richness. He added that public preference is highly correlated with expert judgm ent with regard to these detail s of the facade. Seventy percent of the codes regulate primary building materials, including the texture, quality, and color of the materials. One participant commented about Petalumas 2nd Street: We have buildings that are new, but its the right colors, [Figure 5-4D]. Th e architect, whoever did it, did a really good job-the look, and the colors, and everything else. Hedm an (1984) wrote that complexity, detail, and color influence the effect of sunlight and shadow. When asked if there was any feature about Kentucky Street that would ma ke people want to walk ther e, one participant commented, Certainly the Victorian color scheme of all the bu ildings is just pleasing. You see buildings that are bright pink and bright blue wi th all the ornate trim. Another participant, remarking on colors on the same street, had an entirely different pers pective: The earth tone s and toned down colors, for me, are very soothing on the visual.
100 Outdoor Dining The literature primarily discu sses outdoor dining, such as cafes, as a component of complexity, transparency, and human scale. Curran (1983) noted that cafes, with seating next to buildings and extending into spaces, give a supportive transition zone for the main function of walking. Outdoor dining is not a prominent feature on either of the streets used for the interview, but several of the participants commented on outdoor dining. When asked what captures his attention, one interview participant mentioned that when a restaurant changed hands, the new owners put in an outdoor seating area with tabl es and umbrellas (Figure 5-5A). He stated: I noticed a difference [that] when they had it and when they didnt, it added a whole other depth, and whole new dimension. I never went to the restaurant before because it never stood out even though I walked by it every day. All of a sudden you see umbrellas and chairs, and it seemed instantly inviting to me. Public Art Only 27% of the codes specifically regulate public art, but those that did made it a priority item on the streetscape. For example, Guideline CC 8: District Wide Guidelines for Community Character, of The City of Pasadena Central District Specific Plan (City of Pasadena, 2004) stated: Incorporate Civic Art. The intent is st ated as: Civic art provides multiple and layered expressions of local history and culture. It contri butes to local identity and the unique qualities of place (p. 136). When asked if complexity encourag es people to walk, one participant gave an enthusiastic reply: One of the biggest draws is the fountain [Figure 5-5B]. People come to it because you have three tiers there. You know, you have the faces on there. The art is very different that you dont normally see. Details are very important, adding the little stones to it [the fountain], adding the faces. People walk by, right to the fountain and say, Oh, its beautiful. They want to touch it. Color and movement attracts them. Marcus and Francis (1990) agre ed, stating that art should in corporate steps or ledges so that people can get close to the art for a sens ory experience. Figure 5-5C shows a sculpture,
101 which invited touching, in a small courtyard of th e historic street in Healdsburg. A strong arts orientation can become an identifying theme that helps to humanize and add meaning to the environment. Even utilitarian components, such as fireplugs, manhole co vers, and fencing, can become art (Paumier, Ditch, Dimond, & Rich, 19 88). When asked if there was enough variety on 2nd Street one participant replied, No, I think thats whats missing. When prompted, he added, Art pieces, public art in the middle. You want to go see what that is. Building Projections/Facade Patterns Building projections and facade patterns are proposed audit features based on the high number of codes that included them and the in terview comments. The importance of pattern for creating walkable streets is also supported in the litera ture. Smith (2003) noted that architectural style is not what conveys the aesth etic message, but abstract featur es, such as the lines and edges (of windows, doors, lintels, balconies, and walls), which create patterns. Pattern from windows and other features is demonstr ated by the building shown in Figure 5-5D on First Street in Livermore. Complexity of the buildings adds to comp lexity of the street. Hypothesized, but nonvalidated features, such as building projections, awnings an d overheads, doors, and primary building materials, are significant features because they play a large role in creating pattern, which is a basic design element cr eated by repetition of features. The Pasadena Central District Specific Plan, (City of Pasadena, 2004), District Wide Guidelines for Building Design, includes Guideline BD 3: Unify and Articulate Building Facad es. The intent of the guideline is described as follows: Ultimately, all buildings need to make a positive contributionA set of responsive, regulating proportions will contribute to a coherent building design and promote architectural unity within the Downtown. Pr oper articulation of a buildings facade will add to the richness and variety of Downtown architecture. (p. 154)
102 When asked about variety on 2nd Street, one part icipant compared it to streets in Ventura and Los Gatos, California, saying, There every bu ilding looks different. I think its one thing we dont have here. The buildings almost all l ook kinda the same, a little too similar. Although pattern is not regulated as a specific feature in the c odes, many of the codes note that pattern is an important urban design quality to achieve primarily through the regulation of other features. The codes typically use the term pattern in describing the intent of the design standards. Pattern is described as the concept of continuity and rhythm in the relationship of building components. For example, The City of Pasadena Central District Specific Plan, (City of Pasadena, 2004), Building Design Recommendation BD 3.3 stated: Respond to the regulating lines and rhythms of adjacent buildings that also support a street-oriented environment, regulating lines and rhythms include vertical and horizontal patterns as expressed by co rnice lines, belt lin es, doors, and windows. (p. 154) Some of the codes describe a pattern of building openings and di stance between doors as being important. Recommendation BD 3.5 of the Pasadena code stated: Provide a clear pattern of building openings (p. 154). Curran (1983) said that patter n, which he equates with comple xity, is one of three basic variables that affect the quality of a public space. Although pattern might be considered the generator of the UDQ of complexity, repetition of features create the patt ern, such as repetition of the lines of windows, doors, and building edges. The pattern these features create can be observed and counted, making pattern an appropriate audit item. When asked about complexity of the street, one interview participant stated, The details of the build ings, the windows, they have added character. Its not ju st flat front spaces. I like the aw nings (Figure 5-6A), and theyre all unique little spaces. Kentucky Street has more grooves so you want to stroll it and see whats around the corner.
103 Much of the pattern and detail that creat e complexity are accomplished through building projections and materials, and 77% of the codes regulate building projections. Many of the codes (83%) regulate the depth of awni ngs and overheads. Those that re gulate awnings typically also regulate marquees and balconies, colonnades and arcades, and bay windows. Curran (1983) noted that awnings and arcades are important. They give the street s visual cohesion and complexity, and they extend indoor activities to support the commercial activity of the street. When asked what features en courage people to walk on 2nd Street, one particip ant said, I think the awnings [Figure 5-6A] for one because it br ings something physically off the building. Two of the interview particip ants recognized the importance of projections when they commented on the flat wall of the theater on 2nd Street. One participant said: This whole side [of 2nd Street] you have the theater building and its again, its flat-no windows, no glass. They helped by putting up th e movie posters [Figure 5-6B]. But when youre looking down, you dont see it, the metal frames, really, if some were protruding out maybe. Another participant echoed that thought: I think the movie theater has created that problem with that whole side because its just a blank wall. Smith (2003) wrote that the windows and walls of each buildi ng create a secondary pattern to the super-p attern of all the buildings on the block, and a blank wall disrupts the pattern Hedman (1984) noted that complexity and richness of detail, repeated fr om building to building, influence the way that sunlight will create shadow patterns (Figure 5-6D). In his book, Great Streets Jacobs (1993) described a medieval street, Via dei Giubbonari, in Rome, as having building facades richly detailed with a constant cha nge of brightness and shadows as light passes over shutters and cornices, sills and frames, signs and lights, a nd downspouts. One participant talked about the light on Kentucky Street: The colors and the ligh t and everything is sort of warm and inviting, like it makes you feel at home and comfortable. These concepts ar e supported in the codes with
104 many of the codes regulating facade details, such as cornices, pilasters, expression lines, and ornamental relief with the speci fic intent to cast shadows. Other sources of pattern are th e turns and angles of roof s ilhouettes. Stamps (2000) stated that the shape complexity of the building silhoue tte (Figure 5-7A) is crit ical to recognizing the building and that complexity can be determin ed objectively by assessing geometric properties (angles and turns) of the roofline shape. Hedm an (1984) wrote that the number of turns and angles contribute to visual pattern and complexity, adding that the pattern of a repeated silhouette can also create vi sual unity. Section 9 of The Pasadena Central District Specific Plan (City of Pasadena, 2004) supported this notion with Guideline BD 8: De sign Roof Silhouettes. The intent stated: A buildings silhouette can provide a memorable image.The rooftop should be interesting and favorably add to Downtowns skyline (p. 159). Paving Materials A variety of paving materials is often used to create a pattern in the sidewalk and streets for a cohesive effect. Paving materials is a proposed audit feature because paving materials and textured sidewalks are regulated in 30% of the codes, and there are num erous citations in the literature. Curran (1983) discusse d the use of paving materials to organize, link, and subdivide spaces, particularly with pattern in the ground treatment. He stated that the rhythm and repetition in the pattern helps to discern distances and k eep pedestrians in clearly marked areas. One participant recalled a street in Los Angeles wh en thinking of memorable streets: They put pavers in the whole strip. I remember the pave rs because it made it very much different. He commented on the pavers on 2nd Street: The pave rs that go across, you dont see it everywhere. People remember to cross at the pavers.
105 Parking Parking is a proposed audit feature because pa rked cars are regulated in 83% of the FBCs through the requirement of parking bays. They are considered an important street feature because they provide a buffer between the pedestrian and moving traffic (Figure 5-7B). They also promote pedestrian use by providing short-term parking. Parked cars are regulated by code through the provision of on-street parking for vehicles. However, many of the codes also recommend parking structures in liner buildings to promote the park once, pedestrian first concept. Not everyone agrees that on-street parking is important. When asked if walking was a pleasant experience on Kentucky Stre et, one participant replied, W e actually wish there were no parking, no cars at all on Kentucky Street. It would be a perfect st reet where parking could be at either end and would cause people to just walk up and down the street. Paumier et al. (1988) stated that the way parking is handled is one of the most important issues for a quality place for people. They explained that park ing frontage on key pedestrian stre ets must be strictly controlled and parking structures should be encouraged. Several of the interview participants had an opinion on parking. One participant stated: The public garage is great. Parking is importa nt. But she also lamented the railings and elevated sidewalks on 2nd Street: The parking and sidewalks are horrible. Theyre just horrible because anybody who parks has to walk in the street to get to the sidewalk. They cant walk from their car to the sidewalk. One participant talked about a study Petaluma had done on why people do not go to the historic downtown. The c ity noted that the number one complaint was no place to park--although all the street s have parallel parking and Ke ntucky Street has one side of diagonal parking. With further research, they f ound that people did not know how to parallel
106 park, so unless a diagonal space was available, in their mind, there was no parking. Another participant compared Kentucky Street and 2nd Street saying, When youre walking, you cant see across the street [Kentucky] because of the [parked] cars. I mean you cant visually see it. When you are walking in the new area [on elevated walks on 2nd Street], you can see horizons and vistas. Summary The features in the complexity model are st rongly supported by the literature, the user comments, and their prevalence in the FBCs as significant features for a walkable urban street. Approximately 53 different featur es are regulated by the FBCs th at collectively create the four audit features for complexity. Three of the nonvalidated features-bu ilding projections, paving materials, and parking-can be measured and reco rded and are proposed to be added to the audit model. They are regulated in many codes and the users felt they were important for a walkable street. The complexity model is one of the stronger models in the audit, and many features related to complexity are regulated in the codes, which suggest that the FBCs have the potential to create a walkable urban street that is high in complexity. Human Scale Model The UDQ o f human scale was found to have th e third highest desc riptive power for a walkable urban street in the street survey. Ewing et al. (2005) de scribed human scale as follows: Human scale refers to a size, texture, and articulation of physical elements that match the size and proportions of humans and, equally important, corresponds to the speed at which humans walk. Building details, pavement texture, street trees and street furniture are all physical elements contributing to human scale. (p. 43, Appendix 2) Orr (1985) stated that features, which are in proximity to the walker and have dimensions that relate to the human body, such as street trees, architectura l detail, street furniture, and pavement texture, all contribute to human scale. Many of the codes include a reference to human
107 scale. For example, The Pasadena Central District Specific Plan (City of Pasadena, 2004), District Wide Guidelines for Building Desi gn includes Guideline BD 7: Emphasize HumanScale Design. The intent of the guideline is descri bed as follows: The individual interacts with th e street level of a building in an intimate fashion, and this is likely to influence our perception of the entire place. If emphasis is placed on the human scale, buildings will communicate that Down town is an inviting and pleasant living environment. Rich visual details at the street level add interest and character to the facade, setting the stage for an active street environment and reinforcing pedestrian comfort. (p. 158) Audit Features for Human Scale in the FBCs The Phase I audit included the five features listed for the human scale model (Adapted from: Measuring Urban Design Qualities Related to Walkability: An Illustrated Field Manual Measuring Urban Design Qualitie s Scoring Sheet, Clemente et al., n.d.). Although 35 features were originally hypothesized for human scale in th e Ewing et al. study, only five were validated for the audit: Number of long sight lines (both sides, beyond study area) Proportion of windows at street leve l (your side, within study area) Average building heights (your side, within study area) Number of small planters (your side, within study area) Number of pieces of street furniture /items (your sides, within study area) Close to half of the complexity features are regulated in the codes. On average, 40% (2.4 out of 6) of the validated feat ures for human scale are regulated in each code. Building heights appear in 29 codes (96%) and first floor wi ndows in 27 (90%) of the codes. The number and percent of codes that regulate each human scale feature are as follows: 29 (96%) Building heights 27 (90%) First floor windows 14 (47%) Street furniture 6 (20%) Small planters 5 (17%) Long sight lines
108 The human scale model in the audit scored in the middle of the models for both the historic and FBC streets. Although the historic streets had a higher average score in the audit, three out of the top five highest scores for human scale were on streets built from Form-Based codes, including Mountain View, Hercules, and Livermore. The codes for these communities all regulated three out of the five audit features, including building height, first floor windows, and street furniture. However, all five of the audit features, including small planters and long sight lines, were present and recorded in all three of the streets. The feature of long sight lines is regulated in only five codes, possibly because it is difficult to regulate as a design f eature since it is affected by many other features within the street corridor. Building height, street trees, and building projectio ns can all affect long sight lines, which is defined by Ewing et al. (2005) as the ability to see about three city blocks into the distance at any point during the walk through the block. The FBC streets all had at least one long sight line (a negative f eature for walkability), primarily because the streets are new and street trees on these streets are young small trees wi th little canopy (Figure 5-8A). The arching canopies of large street trees are the primary f eature to affect long sight lines. The tree canopy is what provides the sense of enclos ure and acts as a ceiling to provi de the human scale, which is why long sight lines are also cons idered in the enclosure model. Although long sigh t lines are not directly regulated in the codes, they are indirectly regulated thr ough other features, such as street trees, building setbacks, street width, sidewalk width, and heights of bu ildings. These features are all regulated in the Herc ules and Livermore FBCs. Small planters are another f eature that was not regulated in the codes, but appeared numerous times on the streets. Small planters are regulated in 6 out of the 30 codes reviewed, yet they appeared in large numbers on all the FBC streets surveyed with the exception of Gilroy
109 (which had large in-ground perman ent planters). Small planters are those that appear to be permanent. They are not in-ground, but they are also not small enough to be taken inside. Most of the small planters along the FBC and historic streets were of differe nt styles, shapes, and sizes. Some appeared to have been placed in fr ont of businesses by the owners. Some streets had high numbers of large, heavy planters because th ey were used to cordon off seating areas for outdoor cafes in the diagonal parking spaces and on the sidewalks (Figure 5-8C). The use of small planters is an example of a feature that might not be re gulated but appears on the street through other means. Regulated FBC Features Related to Human Scale Regulated features related to hum an scale are linked with an a udit feature (in bold) to show how regulated features can indirect ly or collectively create the human scale features on the street. For example, small planters are not regulated but th ey are often considered to be street furniture or public art. Number of long sight lines may be regulated in the code th rough: street trees (spacing and type), building heights, building setbacks, street width, sidewalk width, traffic lights, terminated vistas, landmarks, and signage. Proportion of windows at street level may be regulated in the codes through: storefront window shapes, display windows, window propor tions and size, percent fenestration on the facade, window placement pattern s, and style of architecture. Average building heights may be regulated in the code s through: architectural style (historic buildings), scale and mass to matc h existing buildings, building type, building proportions, building height to width ratio, and building hei ght to street width ratio. Number of small planters may be regulated in the c ode through: street furniture, miscellaneous street items, and public art. Number of pieces of street furniture may be regulated in the code through: benches, pedestrian lights, trash recepta cles, planters, bollards, banners, bike racks, chairs, tables, umbrellas, clocks, newspaper racks, shade st ructures, bus stop shelters, kiosks, parking meters, drinking fountain, signs, and mailboxes.
110 Proposed Audit Features for Human Scale The literature, code review, and observations of the interview participants support the existing audit features. Three features are propose d to be included as an audit feature in the human scale model. Street trees are proposed because many of the codes (73%) regulate common tree spacing and type, 67% regulate trees in wells or la ndscaped beds, and 57% regulate the number of trees. Coordinated pieces of street furniture is proposed as an additional audit feature to count those pieces of furniture that are coordinated or belong to a set separate from miscellaneous street furniture. This audit feature is proposed because many of the codes emphasized coordinated furniture for a cohesi ve look. Facade detail and decoration were proposed for imageability, but they were also in cluded under human scale because the literature shows that buildings with detail are perceived to be less massive and more human scale. The proposed features are listed with a qual itative description for an audit. Street Trees: Regulated features such as trees in we lls/landscaped beds, common tree spacing and type, trees in planters, trees in landscaped median, and proportion of sidewalk shaded should be counted in the au dit as number of street trees. Coordinated Street Furniture : Regulated features made with the same details and materials such as benches, pedestrian lights, trash receptacles, plan ters, bollards, bike racks, clocks, drinking fountain, signs, and mailboxes should be counted in the audit as number of coordinated pieces of street furnishings. Faade Detail and Decoration : Regulated features such as cornice/parapet with cornice cap, regularly spaced windows, pilasters, sign bands, storefront cornices, transom windows, awnings, display windows, bulkheads, li ght fixtures, trim, medallions, moldings, decorative panels, and architectur al style should be counted in the audit as number of buildings with faade detail and decoration. Expert and User Perspectives The literature, comments from the users, and frequency of regulation in the codes supports the value of human scale for a walkable urban street. Two audit features number of long sight
111 lines and proportion of windows at street leve l, are also included in the enclosure and transparency models on the audit. They are discu ssed in detail in the review for those models. Average Building Heights Hedman (1984) noted that the s ilhouette of the roof line helps to contain the space as long as the roofs are approximately the same height and united by a similar pitch (Figure 5-8B). He explained that two walls must c ontain the space, and a uniform he ight of street space gives the street crosssection strong unifying proportions. One intervie w participant commented on the height of the buildings on Kentuc ky Street: The street is inviting in that there is nothing higher than two levels, and really, for the most part theres nothing higher th an one level so you dont feel dwarfed as a pedestrian. You know its just sort of comfortable. Number of Small Planters Although small planters are regulated in few codes, they are considered to be important to human scale (Figure 5-8C). The development regulations of the City of Brentwood Downtown Specific Plan (City of Brentwood, 2005, re trieved April 12, 2006, from http://www.ci.brentwood.ca.us/department/cd/pl anning/dow ntown_specific_plan/downtown_spe cific.cfm ) stated: Public gathering spaces should be detailed with decorative, pedestrian-scaled site furnishings, including seati ng, free-standing planters, etc. ( p. 50). One interview participant talked about a plan to put more planters in the courtyard on 2nd Street: They are going to put some planters inside here, and the planters wi ll bring warmth, because of the green. We have some trees; we have trees that, again, add the warmth to it. Buildings with Facade Detail and Decoration This feature also appears in the imageability model, but applies to human scale as well. Street trees and street furniture are the two feat ures most closely associated with human scale,
112 but building details at the street level are also important. Orr (1985) noted that architectural elements influence the scale of buildings and sens e of space. Stamps (2000) stated that surface detailing had the largest effects on preference. Many of the codes regulat e facade detail either through architectural style (highlighting the details typical of that style) or through a diagram of desirable details. The building design guidelines in the Pasadena Central District Specific Plan (City of Pasadena, 2004) include details such as light fixtures, canopies, awni ngs, and display windows. They encourage separate storefr onts, details that provide eviden ce of artistry and craft, and windows with multi-layered displays. Window displa ys were mentioned by several interviewees. When asked what, if anything makes people want to walk on Kentucky St reet, one participant noted: The window displays that the retailers are doing. There s just a lot to take in. Unwin (2003) explained that building details should be used to interrupt the vertical thrust of buildings (with belt courses), and finish the height (with cornices) to infer a roof over the street and imply human scale. Another quality of facade features is that they can make a building seem less massive. Stamps (1998) found that facade articulation (projecting and receding parts) and partitioning were associated with less appa rent mass because vertical breaks slow the movement of the eye upward. Figure 5-8D shows ex amples of partitioning on Monterey Street in Gilroy. Curran (1983) said that one di mension of streets, the lengt h, can be manipulated with the use of curvilinear patterns, bends, and building pr ojections to produce encl osure. One participant noted that: Adding depth to it [the building faade along the street] is really impor tant, it gives it more character, and I dont lik e straight lines. If you have a li ttle, you know, curve or something, or if you add a little angle, whether its the ro ad or the street instea d of having it straight on, I think it looks better when they add some different cuts to it.
113 Street Trees Ford (2000) declared that trees help turn spac es into places (p. 120), and can give a street a unique identity even when the architecture is nondescript. The Pasadena Central District Specific Plan (City of Pasadena, 2004), District Wide Guidelines for the Street Environment includes Guideline SE 4: Plant and Maintain Street Trees. The intent of the guideline is described as follows: Street trees provide numerous benefits and ar e an indispensable part of the Downtown environment. Most obviously, they enhance the vi sual quality of the area. Street trees also provide cooling effects and contribute to the sp atial definition of the street to create a human-scaled space with a comfortable sense of enclosure. In general, street trees add a gracious quality to Downtown. (p. 140) Paumier et al. (1988) noted that street trees are probably one of the best downtown urban design investments because they provide a unifying visual element. Burden (2006) said the green area where street trees are planted adds signifi cantly to aesthetics a nd placemaking, creating a more pleasant walking environment and increasing walking. The Downtown Gilroy Specific Plan (City of Gilroy, 2005) stated: The addition of street trees in many cases can be the single biggest improvement to a revitali zing community. It is the number one improvement priority for the Downtown. (p. 104). Rubenstein (1992) and Burden (2006) explaine d that trees have functional and economic benefits, including climate control and environmental engineering (a ir purification, noise, glare, and erosion control). Plus they have architectu ral and aesthetic uses, such as space definition, screening, continuity, and view control. Arnold (1993) stated that tree rows connect ends of buildings, and tree patterns that reflect building form connect the building to the street, adding that trees are more important today because buildings lack complexity in their archite cture. He also explained that trees vertically define a space with a ceiling of branches, and th ey horizontally enclose th e area with their trunks.
114 One interview participant, when asked if Kentucky Street had a room-like quality, talked about trees: The trees lining the street. It just has that sort of cozy [feel], like you want to stay longer on the street. A small number of the codes (17%) also regula te shade on the sidewalk, either by trees or overhangs (Figure 5-9A). When asked what make s people want to walk on Kentucky Street, one participant noted: Theres a lot to take in. Its tree lined, theres grates Another participant, when asked what makes the street a comforta ble space, replied, Landscaping, trees, how the trees are set into the area. Not all the interview participants agreed on th e importance of street trees. One participant commented: From a visitors point of view, it s nice to have trees growing. From a vendors viewpoint, I hate the trees b ecause it blocks the view. Wev e got windows up above [on the building] and it blocks them. Another participant talked about the trees on Kentucky Street saying: They could have done be tter trees for sure; even palm trees would have been cool. Something that bursts up above the buildings would have been awesome, and it would have totally canopied it. Coordinated Street Furnishings This feature is proposed in addition to one of the existing audit features, number of pieces of street furniture. Streetscape is important because it plays a ma jor role in creating a sense of identity. Streetscape unifies an ar ea and provides for the comfort a nd safety of users. One key to the use of streetscape, emphasized in many of the codes, is the unifying effect of coordinated street furnishings. If street furnishings are ha phazard and mis-matched it is likely to have the opposite effect, that is, a chaotic lo ok that tends to create a lack of unity and loss of sense of
115 identity. However, one particip ant, when asked about what made the street interesting, commented on the lack of uniformity as a possible desirable quality: Theres definitely a lack of uniformity, which we enjoy to a part, because we are all unique and all individual and all have different businesses. There are different things that streets like ours do that create more [uniformity] like the planter boxes that line the street are all the same. Paumier et al. (1988) noted that repeated use of street furnishings creates a visual overlay that reinforces the organizing struct ure of the streets (Figure 5-9B). The Pasadena Central District Specific Plan (City of Pasadena, 2004), Public R ealm Design Guidelines for Street Environment, Guideline SE 5 stated: Provide Ample St reet Furniture. The intent included: Walking downtown should be a pleasant and comfortable experience. Long walks without places to pause and rest may become daunting fo r some pedestrians. Street furniture, when combined with street trees and proper ligh ting, humanize and communicate the true nature of downtown streets. Most importantly, furnishings should include benches and trash receptacles. (p. 141) The guidelines also include a recommendation (SE 5.1) for placement of furniture, noting that benches and trash receptacles should be placed at frequent intervals for pedestrian comfort and use. When asked if anything on the street enc ourages people to intera ct, one participant said he did not see a lot of interac tion: Even though I know they have benches out there, I dont see a lot of the people using the benches like I thought maybe they would. Out in front of our store they do because its a food place. One interv iew participant commented on the location of benches, planters, and tras h cans on Kentucky Street: The city decided to add benches, so we ha ve a bench in front of our window. Nobody had any say in the location. It was ju st bolted and then Id rather not have one in front of my window, it blocks access. And the egg-shaped planters, [Figure 5-9C] its very charming, but nobody had any say in it, and the plants mu st be maintained by the merchants. When they put in the garbage cans, theyre nice little quaint trash cans; they didnt put one in on this side of the street. They finally put one on this side of the street but its more toward my business than the bar.
116 One participant, when asked what makes the street a comfortable space, replied: Garbage accessibility, so that you dont have to walk two blocks to throw something awayalso benches. Another participant replied, I like the benches. You can go and relax and sit and people watch. Pedestrian street lights are an important functional and aesthetic street furnishing. The Pasadena Central District Specific Plan (City of Pasadena, 2004) noted that the size and scale of the lights are important. The smaller, human-scaled fi xtures suggest the street is safe to walk and the sidewalks are the pedestrians realm. Sixty percent of the codes regu late pedestrian scale street lights (Figure 5-9D). One participant talked about pedestri an street lights, remembering a street in Los Angeles that he had visited: I remember still to this day the lights going down because theyre big, huge lights and the sconces and everything were gorgeous, and I still remember thinking, walking down there, this is gorgeous. I still remember the lights, tick, tick, tick, all the way down. Those big lights make a difference. When asked what features encourage people to walk, the same participant commented on the lighting on 2nd Street: We have individual lights on the building and then we have the light posts. Sometimes when you get a crowd of people, the light posts seem like theyre in the way, but overall I think they did that here very well. Its that old fashione d looking type of light. Summary On average, the codes regulate only about half of the human scale audit features, but they also regulate many othe r features, such as type of window s, building proportions, and street furniture, which are related to human scale. When brought together on the street, these features create the audit features in the human scale model. Two features derived from the FBCs; building facade details and coordinated street furniture, plus one non-validated feature, street trees, are strongly suppor ted in the literature and in the FBCs as noteworthy features for
117 human scale. These features are proposed to be added to the human scale model on the audit. Many regulated features link to the audit features and result in the audit features for human scale being present on the street, whic h suggest that the FBCs have a high potential to create a walkable urban street base d on the human scale model. Enclosure Model The UDQ o f enclosure was found to have the second lowest descriptive power for a walkable urban street in the survey, putting it just above tran sparency. Ewing et al. (2005) described enclosure as follows: Enclosure refers to the degree to which street s and other public spaces are visually defined by buildings, walls, trees, and other vertical el ements. Spaces where the height of vertical elements is proportionally relate d to the width of the space be tween them have a room-like quality. (Appendix 2, p. 42) The literature has many descriptions of enclosure in the outdoor built environment. Alexander et al. (1977) stated that buildings on streets should form a continuous fabric with surrounding buildings, and the height and setback s hould not vary too much to create enclosure. Hedman (1984) noted that the height of the wa lls is crucial to the sense of enclosure and orientation. Trees have been seen as important to enclosure becau se they form a wall of green, allowing pedestrians to feel separated from vehi cles (Burden, 2006). Many of the codes include a reference to enclosure. The Pasadena Central District Specific Plan, (City of Pasadena, 2004), Public Realm Design Guidelines for Street Enviro nment lists Guidelines SE 3: Protect and Shade Pedestrians and SE 4: Plant and Maintain Street Trees. The design criter ion explained: A street should read as a well defined space ( p. 139) and recommendations include: Emphasize the planting of street trees to provide overhead cover, and buildings adjacent to sidewalks should provide overhead cover in the form of canopies, awnings, and overhangs.Plant street trees to define the street and sidewalk, em phasize the consistent use of tree species, size and sp acing along a street to create a pleasant rhythm and reinforce the space of the street. (p. 140)
118 Audit Features for Enclosure in the FBCs The Phase I audit included the three features listed below (adapted from: Measuring Urban Design Qualities Related to Walkabi lity: An Illustrated Field Manual Measuring Urban Design Qualities Scoring Sheet, Clemente et al., n.d.) Although there are only th ree features, two are counted twice because the quality of enclosure is dependent on both sides of the street having a street wall, and the proportion of s ky is important in all directions. Number of long sight lines (both sides, beyond study area) Proportion street wall (your side, within study area) Proportion street wall (opposite side, within study area) Proportion sky (ahead, beyond study area) Proportion sky (across, beyond study area) The audit features are not highly regulated in the codes. On aver age, one out of three of the validated features is regulated in each code. However, one feat ure, percent of street wall, appeared in 24, or 80%, of the codes. The numbe r and percent of codes that regulate each enclosure feature are as follows: 24 (80%) Percent of street wall 5 (17%) Long sight lines 2 (6%) Proportion of sky The historic streets ha d a higher average score in the audi t than the FBC streets. Four out of the five lowest scores for enclosure were on streets built from Form-Based codes. However, in the four highest scores for enclosure, three F BC streets, in Livermore, Gilroy, and Petaluma, scored the highest, along with the historic street in the town of Palo Alto. The codes for Livermore, Gilroy, and Petaluma regulated only one f eature (percent street wall) out of the three audit features. A review of the audits showed high scores for percent of street wall, typically 95% to 100%. The high scores may have been due to the fact that all of the codes indirectly regulate the stre et wall through various other featur es such as garden walls and
119 build-to lines. Many also had bulk provisions that include maximum and minimum building widths and side setbacks, a nd maximum and minimum lot widths. Circulation and open space provisions for pedestrians also affect the stre et wall, including courtyards, parks, plazas, alleyways, midblock passageways, and building entr ances. Also the type of building, such as residential, (with porches, stoops, and raised fo undations) and courtyard buildings or commercial buildings (with multiple store fronts) affect the percent of street wall. Regulated FBC Features Related to Enclosure The features which are related to enclosure th at are regulated in the FBCs are linked with the audit features to show how the regulated feat ures can collectively create the audit feature on the built street. Number of long sight lines and percent of sky ahead sh are many features that influence both, but they ar e listed with the most relevant features for each. Proportion of street wall may be regulated in the code through: maximum and minimum building widths, side setbacks, build-to-lines courtyards, parks, plazas, alleyways, midblock passageways, building entran ces, and type of building. Number of long sight lines may be regulated in the code th rough: street trees (spacing and type), building heights, building setbacks, street width, sidewalk width, traffic lights, terminated vistas, landmarks, and signage. Percent of sky across/ahead may be regulated in the codes through: arcades, colonnades, balconies, awnings, overhangs, shelters, street trees (spacing and type), building heights, building setbacks, street width, sidewalk width, traffic lights, terminated vistas, landmarks, and signage. Proposed Features for Enclosure Four features are proposed to be included as audit features in the enclosure model: awnings and overheads, safety features, street trees, and ratio of building height to st reet width. Awnings and overhangs are regulated in 83% of the code s, and arcades in 80%. Both awnings/overhangs and arcades were cited by 83% of the interview participants. Safety features are proposed because many interview participants cited several features that they related to safety. Street width
120 is proposed because it is a non-validated feature th at is regulated in 67% of the codes. Although street width is a contributing factor for enclosure, the ratio of the width to building height is supported in the literature as being more important than st reet width alone. Therefore, the proposed feature includes both heig ht and width. Street trees are also proposed for this model because in addition to human scale, street tr ees are important features for enclosure. The proposed audit features are listed with a description of the quantita tive measure of the feature for the audit. Awnings and Overheads : Regulated features such as awnings, overhangs, and arcades should be counted in the audit as n umber of awnings/overhangs/arcades. Safety Features : Regulated features such as raili ngs, street trees, landscaped buffers, width of sidewalk clear zone, curb extensions large planters, pedest rian street lights, parallel and diagonal parking, paved surfaces, cu rb cuts, and car speed should be counted in the audit as number of safety features. Street Trees : Regulated features such as trees in wells/landscaped beds, common tree spacing and type, trees in planters, trees in landscaped median, a nd proportion sidewalk shaded should be counted in the au dit as number of street trees. Building to Street Ratio : Regulated features such as street width, sidewalk width, median width, landscape buffer width, and building height should be counted in the audit as ratio of building height to street width. Expert and User Perspectives The literature, the codes, and observations of the interview participants support the enclosure model as being important for a walkab le street and they support consideration for additional features in the audit. Safety features were not hypothes ized in the Ewing et al. (2005) study as features for walkable streets, but several features related to safety were on the list. The interview participants cited many features and related them to sa fety, such as railings, marked street crossings, speed of cars, parked cars, the width of the clear zone on the sidewalk, one-way streets, and the texture of the sidewalks and streets (as tripping hazards). Although this proposed
121 audit feature of safety features is a catch-all for many types of f eatures related to safety, it was put in the enclosure model because most of th e features are also re lated to enclosure. Proportion of Street Wall Curran (1983) noted that the im portance of the street wall is the expression of containment: the wall creates the form of the street that becomes the contai ner within which the street functions. Moughtin (1992) explained that for the street to function as a place or an exterior room, it must be a completely enclosed unit. Un win (2003) stated that th e property of enclosure is affected by the room-like feel that is coll ectively created by the wa lls and openings in the buildings. But enclosure is also a perception th at varies between indi viduals, based on their tolerance for an enclosed space. When asked if 2nd Street had a room-like quality, one participant commented: I dont get the feel, theres no closure on the end. To me, it feels really open still, unlike San Francisco where you dont feel like its open to the sky because of the tall buildings. On 2nd Street, you have the lower sidewalk, then the upper sidewalk, then the building so its almost like a coliseum. Its too open to be a room to me. One participant commented on the street trees when asked about th e room-like quality along Kentucky Street: I agree, the canopy helps, but its not dense, yeah, and you could stand out in the street or on the si dewalk and see someone for a pretty good distance. However, another participant commented that Kentucky St reet felt contained by the buildings, awnings, and trees. Long Sight Lines and Percent of Sky Across/Ahead Long sight lines and proportion of sky are rela ted features not direc tly regulated in the codes, but they are indirectly re gulated by features that are in th e codes. Both are created by the void between the buildings and ar e affected by elements, such as building heights, building setbacks, street width, sidewalk width, traffic lights, street trees (both spacing and type),
122 terminated vistas, and signage. Proportion of sky is also affected by the use of arcades, colonnades, balconies, awnings, overhangs, and shelters (Ashihara, 1970; Ewing et al., 2005; Jacobs, 1993; Hedman, 1984). The property of enclosure is also affected by a sense of distinct boundaries, another individual perception that is a ffected by long sight lines. Although long sight lines are considered a negative feature for a walkable street (as opposed to distinct boundari es) some of the codes encourage view corridors as part of the commun ity character. Preservation of view corridors is usually seen in codes for communities that have outstanding natural features that are scenic and regionally important, such as mountai ns and water views, or historic features such as towers or civic landmarks. Petaluma has a historically important waterfront along the Petaluma River. The Central Petaluma Specific Plan (City of Petaluma, 2003, re trieved April 12, 2005, from http://www.cityofpetaluma.net/cdd/cpsp.html ) includes several references to the river, including Goal 6: Maintain Visual Landm arks. The goal stated: Central Petaluma has a strong sense of identity that, to a great extent, derives from the presence of the river and the existing landm arks that recall the citys heritage and traditions.To the extent feasible, the visibility of these interesting elements should be maintained. (p. 42) In addition, Goal 5: Orient Activities to the Petaluma Ri ver; also focuses on the waterfront: Land use patterns should be oriented to the Pe taluma River, focusing development toward the edge, providing for continuity of activiti es along it (p. 30). When asked if 2nd Street felt like it had distinct boundaries, one participant replied: Yes, I definitely feel boundaries I dont know if its the rock corners, but I know when Im coming down the street, maybe because there is a dead end [sharp curve], I feel like that side of the street cuts me off.
123 Second Street turns 90 degrees when it comes to a historic building, the Petaluma Mill. The participant did say he was glad the city kept the mill because it is a very old historic building that was visually appealing. Building Height to Street/Sidewalk Width The literature often links human scale and encl osure, noting that many elements, such as building height and street width ratio, relate to bo th (Figure 5-11A). Ashihara (1970) stated that a ratio of 1:1 height to width is the critical point for exterior sp aces. Hedman (1984) agreed that anything over the 1:1 ratio limits the sky view. Al exander et al. (1977) stat ed that the width of the streets should not exceed the building heights. However, Curran (1983) postulated that the ideal height to width ratio can va ry from one culture and era to a nother, and the actual scale of spaces relative to human beings is more impor tant. One interview participant did comment on wall height: If the walls are tall, they feel like they are closing in on you. Several of the codes include di agrams of the height to widt h ratios for different types of streets, depending on the type of building and uses on the street. For example, commercial streets typically have taller buildings relative to the street width than residential streets. Page II-4 of the Regulating Code for the Central Hercules Plan, (2001, retrieved April, 11, 2006, from http://hercules-plan.org/ ) diagram s the dimensions of a four-l ane avenue with a 110 foot right-ofway (ROW) and minimum building heights of two st ories and maximum heights of four stories. Page II-6 diagrams the dimensions of a main street with a 60 foot right-of-way (ROW) and minimum building heights of three stor ies and maximum of five stories. When asked about Kentucky Street (a one-way street with di agonal parking), one participant felt the street had a room-like quality because of th e width: Absolutely, very high
124 walled. It definitely brings you in; its narrow. Another participant felt Kentucky Street was a nice street to walk down because: Its a nice tight street. Its got; its thin, if you will. It gi ves the same air as you would find on Bourbon Street. Its nice. A lot of access to everything, you can reach out and go to so many different things. Regarding sidewalk width, when asked what el ements of the street and sidewalk design encouraged people to interact, a participant said: I think the width has a lot to do with it. Another partic ipant commented, To me a nice wide sidewalk is much more inviting, and I always liked seeing that. Ive noticed when it gets a little crowded, people do this [twist their shoulders]. So if they have it wide enough, it makes it much more inviti ng to people to walk and stroll. Awnings/Overhangs/Arcades Hedman (1984) noted that entrances are a zone of transition between two spaces. Curran (1983) explained that the treatment of the zone can express the interrelationship of the two spaces, encouraging the use of entrance canopies and awnings to extend and overlap the two domains. When asked if Kentuc ky Street had a room like qualit y, one participant noted: on Kentucky Street, they have hugh overhangs that cove r almost the whole sidewalk so if theres a torrential downpour, you can still hang out there. When asked what ma de Kentucky Street pedestrian friendly, a participant replied, There are a lot of awnings on a lot of these buildings so on a pouring down rain day you dont really need an umbrella. When asked about physical comfort on the street, he replied, Again, the awnings for sure, from sunlight, sun exposure. Another participant had this to say about the awnings on 2nd Street (Figure 5-10B): Nice awnings, except in the building that Im in, theres like an overhang that goes around the whole building, and it originally almost looks like its an awning, but its not, because it has all these slots so that the rain comes pouring down and its right in the door and so nobody really thought [that] through. Now, when they built the buildi ng across the street theres real awnings so when you walk in the door you at least have some sort of a break. But when you walk into my door its all pouring down rain.
125 Physical Safety Features Safety features are a group of features that primarily protect the pedestrian from vehicular traffic, but also include general safety features such as pedestrian lights. These are sometimes addressed under provisions for comf ort in the codes. Paumier et al (1988) stated that the most important concept is to provide an adequate sens e of separation and protection between vehicles and pedestrians. Burden (2006) noted that stre et trees create safer walking environments by forming visual walls and distinct edges to side walks that distinguish between pedestrian and vehicular environments. Most of the codes have pr ovisions for features, such as wide sidewalks, landscape buffers with street trees, and parked cars, to help separate people and cars (Figure 510C). The Pasadena Central District Specific Plan (City of Pasadena, 2004), Public Realm Design Guidelines, Street Environment includes Guideline SE 3: Protect and Shade Pedestrians. The intent of the guideline is described as follows: The physical safety and comfort of pedestrian s is critical to th e success of Downtown. Pedestrians must feel they are in a safe situa tion, and that they are a welcome presence in the community. Streetscape de sign and amenities should emphasize pedestrian safety and comfort. For instance, the proper placement of street furniture introduces distances and a perceived protection from vehicular traffic. the overhead cover provided by street trees offers shade and reasonable protect ion from the sun and rain. (p. 139) Recommendations in the code include a mini mum five-foot clear pe destrian passage along public sidewalks, and also locating street amenities in a zone along or near the curb as a barrier to automobile traffic. Elements within the zone should include street lights, parking meters, street trees, trash receptacles, news r acks, and heavy planters. Schmitz and Scully (2006) commented on the perception of safety and the importance of the quality and intensit y of the lighting. They noted that lighting should be bright enough to ensure safety but not so bright to create glare.
126 With regard to comfort and safety of the user, two interview participants expressed frustration with the rail ings along a portion of 2nd street (Figure 5-10D). The railings are along elevated walkways to meet safety standards and one participant complained: These ridiculous railings--the way they designed it and the el evations. They designed it in such a way that in some cases you have to walk half a block in the street in order to get to the sidewalk. So in my opinion, thats ridicu lous and it doesnt make for very friendly walking. Another participant noted: One aspect of the street that people dont care for too much is the railing. It takes away from the old-fashioned feel. I dont like th e look of the railing. In stead of noticing the sidewalks and the buildings, you see these galv anized metal look which is more sterile. You know, if it would have been wrought iron or something old fashioned, it would have been different. One participant mentioned the problems with bicycles on the sidewalks on Kentucky Street: I wish there was a way to enforce bicycles off of the sidewalk, even if it were just poles that they couldnt get through at th e end of the sidewalk. Other f eatures, such as obstructions in the pedestrian pathway and tripping hazards, are al so addressed in most codes. One participant had a very strong opinion about the pavers on 2nd Street: The cobblestones are real. Theyre dangerous and people trip on them a ll the time. Its just horrible. Several features related to safety, which were hypothesized but are in less than 50% of the codes; include midblock crossings, speed tables, and pedestrian crossing lights. Other features that are often included in the codes, but were not one of the hypothesized features, include rightof-way (ROW) width, crosswalk wi dth, pedestrian refuge islands, and minimal driveway cuts in the sidewalk. Summary The difficulty with the enclosure model is that two of the audit feat ures, long sight lines and proportion of sky, are features that woul d not normally be written as a regulation in a
127 code. The other audit feature, proportion of street wall, was the one featur e--out of the three-that was regulated. However, several FBC streets scored very high on the enclosure model because the codes of those towns regulated a high total number of features that affect sight lines and proportion of sky. Three non-validated featur es; awnings, overhangs, and arcades, are proposed as audit features. They are strongly supp orted in the literature and by user comments as being noteworthy UDQ qualities for the enclosure model. Two additional proposed features are derived from the FBCs: ratio of building height to street width, and safety features. Safety features are proposed because a hi gh number of interview partic ipants cited several features related to safety. All of them me ntioned, at least once, some safety concerns that they had while walking on the streets. General concerns incl uded lighting at night (a nd activity at night), tripping hazards, and safe street crossings. The enclosure model has few audit features regulated in the codes. However, based on the number of re gulated code features that create enclosure, enclosure may be considered an impo rtant model for a walkable street. Transparency Model The UDQ model of transparency had the lowest score and therefore the least descriptive power in the street audit. Ewing et al. (2005) described transparency as follows: Transparency refers to th e degree to which pe ople can see or perceive what lies beyond the edge of a street or other public space and, more specifica lly, the degree to which people can see or perceive human activity beyond the edge of a street or other public space. Physical elements that influence transpar ency include walls, windows, doors, fences, landscaping, and openings into midblock spaces (Appendix 2, p. 44). Transparency is cited in the l iterature as a primary concern for streets for two reasons: (a) perceived (psychological) and real safety, and (b) the extension of public/private space. Alexander et al. (1977) noted that details along the street should include windows and arcades to extend the territory between public and private. Schmitz and Scully (2006) explained that retail
128 merchants should be encouraged to include intere sting displays in their storefront windows and be prohibited from c overing the windows. Audit Features for Transparency in the FBCs The Phase I audit included the three features listed below for the UDQ model of Transparency (adapted from: Identifying and Measuring Urba n Design Qualities Related to Walkability : An Illustrated Field manual Measuring Urban Design Qualities Scoring Sheet, Clemente et al., n.d.). Proportion windows at street level (your side, within study area) Proportion street wall (your side, within study area) Proportion of active uses (ahead, beyond study area) In the audit of the streets, Proportion of active uses was determined by the obvious presence of an active business in the buildings and the type of business. Buildings which were empty (out of business) or were used for non-publ ic, low foot traffic businesses were not counted as active uses. In the review of the codes, pr oportion of active uses was recorded as present in a code if the code included a list of permitted uses. Two of the audit features for transparency are regulated in most of the codes with windows at street level in 90% and street wall in 80%. On average, 45% of the audit features (1.8 out of 4) are regulated in each code. The number and percent of codes that regulate each transparency feature are as follows: 27 (90%) Proportion windows at street level 24 (80%) Proportion street wall 5 (17%) Proportion of active uses The transparency model scored the lowest of the five models on the audit of both the historic streets and the FBC streets. The FBC streets, however, ha d a higher average score on the audit, and three out of the t op five highest scores for tran sparency; Hercules, Gilroy, and
129 Livermore, were on streets built from FBCs. Th e codes for all three communities regulated the proportion of windows at street level and the proportion of st reet wall. For example, the City of Livermore Downtown Specific Plan (City of Livermore, 2004) in cludes standards for windows in Chapter 6: Design Standards and Guidelines as follows: 1) Buildings shall include vertically proportioned facade openings; with windows that have a greater height than width (an appropriate vertical/horizontal ratio ranges from 1.5:1 to 2:1). Where glazed horizontal openings are used, they shall be divided with multiple groups of vertical windows, 2) Storefront windows shall encompass a minimum of sixty percent (60%) of the storefront facade surf ace area. Where greater privacy is desired for restaurants or professional se rvices, windows should be divided into smaller panes, and 3) Windows on the upper floors shall be smaller in size than storefront windows on the first floor, and shall encompass a smaller proportion of facade surface area. (pp. 6-21) Regulated FBC Features Related to Transparency The FBC regulated features related to transp arency are linked with an audit feature to demonstrate how regulated features can indirectly crea te the audit features on the built street. For example the codes may not directly regulate proportion of the wall that is window but they might regulate features such as the shape of the window, the size of the window, and where the window is placed, which would all affect th e proportion of the wall that is window. Proportion windows at street level may be regulated in the code through: storefront window shapes, display windows, window propor tions and size, percent fenestration on the facade, and window placement patterns. Proportion of street wall may be regulated in the code through: maximum and minimum building widths, side setbacks, build-to-lines courtyards, parks, plazas, alleyways, midblock passageways, building entran ces, and type of building. Proportion of active uses may be regulated in the code through: a list of permitted uses, recommended uses for street types, and building types. Proposed Audit Features for Transparency Two features are proposed to be included as a udit features in the transparency model. One is a non-validated feature: visible sets of doors that is regulated in a high number of codes
130 (77%). The other, a non-validated feature, m idblock passageways, is proposed to be added because 33% of the users cited it in the intervie ws, and it is regulated in 40% of the codes. The proposed audit features are listed with a description of the quantita tive measure of the feature for the audit. Visible sets of doors : Regulated features such as sp acing of entryways, entryways per building, clear pattern of building openings, a nd frequent cadence of storefront entrances should be counted in the audit as number of building entrances at street level. Midblock passageways : Regulated features such as marked crosswalks, midblock passageways, pedestrian refuge islands, ri ght-of-way width, crosswalk width, and curb extensions should be counted in the audit as number of midblock passageways. Transparency Model FeaturesExpert and User Perspectives The literature and observations of the intervie w participants support transparency as an important quality for a walkable street. In a ddition, the features of building entrances and midblock passageways are supported as important f eatures for a walkable street audit for the transparency model. Windows at Street Level Windows at street level are regu lated in 90% of the codes. Ewi ng et al. (2005) stated that the display window at street leve l, where transparency is most important, is the classic example of transparency (Figure 5-11A). Windows in shops, Curran (1983) noted, make the street level more visually complex by expanding into the street. When asked if windows were important, one participant replied: I think [windows are important] because people are so visual. They want to see, oh, look at those pretty things. They want to see some thing thats appeasing to the eye rather than just a piece of wall [Figure 5-11A]. So I thi nk its a huge part of it actually. People feel trapped walking along a blank wa ll. Theres one building at th e Foundry Wharf. Its creepy walking past it. Its almost the whole bloc k, and its a solid wall. There are no windows so we actually walk on the ot her side of the street.
131 One participant reflected this thought when she commented on the windows in her store: The other thing is being able to see visually inside. I love my space, but there are windows that are opaque in my space, and any re tailer knows you want your windows. Windows are so important to the character and function of the space that most codes dedicate an entire sectio n to the design standards fo r windows. Chapter 4 of the Downtown Gilroy Specific Plan (City of Gilroy, 2005) and Chapter 6 of the Livermore Downtown Specific Plan (City of Livermore, 2004) include archite ctural design guidelines for windows. These guidelines include such stipulati ons as: windows at pedestrian s cale and detail; color variation and detail in the framing; vertically proportione d windows with a greater height than width; windows covering a minimum of 60% to 80% of th e storefront faade; clear glass only; upper floor windows relate to the window pattern on the ground floor; and storefront windows and doors of the same style. Proportion of Street Wall The proportion of street wall f eature is also included in the enclosure model. It was discussed in detail in th e enclosure model review. Proportion of Active Uses The proportion of active uses was not directly regulated in any of the codes; in other words, the code did not specifica lly say a certain percent of uses must be present on the street. But the codes do regulate uses through a list of approved or recommended uses for the zone and/or street where the code appl ies. A central concept of Form-Based codes is that the form of the built environment, rather than the use, is re gulated. Katz (2004) explai ned that the form--the buildings and the configuration of the street--remains the same, but the use changes over time. While the use is regulated in the codes, it is secondary to the regulation of the built form.
132 Use is controlled typically through zones es tablished on the regulating plan and the allowed land use/building types in each zone. Some codes, such as the Gilroy and Livermore codes, simply list the permitted or desired uses by street or district. Chapter 5: Districts, Land Use, and Development Standards, of the Downtown Gilroy Specific Plan (City of Gilroy, 2005) includes a Permitted Use Table, which lists desired uses for certain districts. These districts include the Downtown Historic District, Downtown Expansion Di strict, Civic/Cultural Arts District, and the Gateway District. The Livermore Downtown Specific Plan (City of Livermore, 2004) also includes a table of permitted uses list ed by streets in the downtown, including retail (grocery and specialty goods), eating, drinking, personal services business services, and banks. Building Entrances Curran (1983) said that the proportion of windows, bays, doorways, and other features provide the contrast between tr ansparency and enclosure, with doors providing the functional linkage. The Central District Spec ific Plan of Pasadena (City of Pasadena, 2004) noted that visual transparency is a citywi de design criterion, stating a bu ilding should offer helpful cues about its access and use (p. 156). The importan ce of building entrances is described in the Private Realm Design Guidelines, Building Design; Guideline BD 5: Demarcate Building Entrances. The intent of the guide line is described as follows: Buildings should offer helpful cues to their access and use. A main lobby entrance to a building serves a different purpose than a stor efront entrance to a street level shop. The difference in use should be accentuated in th eir design. Main entrances that are easily distinguishable provide comfort and ease for the pedestrian searching for th eir destination. Prominent entrances also add character, iden tity, and interest al ong the street. (p. 156) The recommendations include providing well -marked, articulated, building entrances oriented to the street. These recommendations re late the size and scale of the entrance to the overall height and width of the building, using highly crafted mate rials or civic art pieces to accentuate the entrance.
133 The Pasadena guidelines also encourage a fr equent and regular cadence of storefront entrances and display windows, separate storef ronts and multiple entrances on long walls, and a greater attention to details at th e street level. When asked abou t windows, one participant said: Ive heard comments from people that like to walk--that its beautiful here. But on the other side of the street [2nd Street], it looks more like busin ess industrial be cause its not open with windows. Its, if you look across th ere, the building facade has a door, a couple windows, and then its plaster. So it kinda loses it until you get down to the end where the restaurant is--then its all wi ndows. It has outdoor seating [Figure 5-11B]. It looks more inviting again. Both the Gilroy and Livermore codes include extensive design guidelines for doors and entryways such as: recessed doors, archways or cased openings marked with a tower above; overhanging roofs and awnings; ornamental lig ht fixtures; and accenting with architectural elements such as columns. The codes also includ e the use of special materials such as paving and decorative hardware; a change in roofline or wa ll articulation; windows in doors to permit views in; and high quality materials and detailing. Conversely, most codes discourage the use of blank walls that are uninviting and which emphasize the mass of the buildi ng. Smith (2003) stated the overa ll sense of proportion of a building is determined by the relationship between windows and walls. If blank walls are unavoidable, codes recommend the use of murals, trellis, vines, or marquis display cases, especially in areas where a midblock passageway occurs between buildings. Midblock Crossings/Midblock Passageways Midblock crossings and related pedestrian features are impor tant for connectivity. When asked what encourages people to interact, one interview participant said the midblock passage from the parking garage to the street (Figure 5-11C) encourag ed people to conveniently meet. She stated that people always remember thos e walkways, once they discover them. Although midblock crossings are regulated in only 13% of th e codes, curb extensions are a related feature
134 that is regulated in 53 % of the codes. Schmitz and Scully (2006) recommended speed tables to delineate midblock crossings. They stated that midblock crossings may reduce the temptation to jaywalk. Some of the interview participants, how ever, liked the fact th at Kentucky Street was narrow and one-way so pedestrian s could cross anywhere. When asked what makes the street comfortable, one participant sa id, You can cross the street easily jaywalking. Another participant mentioned the tightness and width of the street, saying, I m not afraid of getting run over here. One participant complained about the railings along the sidewalk on 2nd Street blocking the crossing: Say, youre walking across the street on this side and your friends are walking across the street on that side and you say, Hey, John, hold on a second, let me go around [the railing]. Yeah, that old feel [without the railing] was you had that easy crossover. Summary Transparency had the highest average number of audit features regulated in each code, and two features, percent of first fl oor windows and street wall are regul ated in 80% or more of the FBCs. Many of the codes also put great emphasi s on specifying the construction material and details for windows, pointing to the importance of windows at the pedestrian level. Although the features are regulated in many c odes, and 50% of the interview participants cited first floor windows, the model still had the lowest scores in the audit. Two features derived from the FBCs: building entrances and midblock passageways are st rongly supported in the li terature and in the FBCs as noteworthy UDQ qualities for transparenc y. They are proposed to be added as audit features in the transparency model. Model Summary The goal of this research was to explore th e po tential of Form-Bas ed codes to create walkable urban streets. The results of this study show that they do have the potential to produce a pedestrian-oriented urban street based on several factors. Perh aps most importantly, the FBCs
135 regulate a high number of urban design details that create, through vari ous combinations, the validated and non-validated urban design features and qualities presumed to be important for walkable urban streets. The FBCs also appear to regulate a high number of features that are preferred by the everyday users of the street. A key concept is th at the codes regulate number of design details for a specified length of street. This is most importan t for the urban design qualities of imageability and complexity. These qua lities rely on high numbers of features to create the synergy needed for a visually complex, interesting, and memorable street. The FBCs which regulated the highest number of features scored the highest on the audit, but the optimal number or minimum number of features is not known. The high audit score suggests that the more features of the built street environment regulated in the codes, the more walkable the resulting street environment. The review of the models has shown that all the models and features are releva nt for creating a walkable street. However, the imageability, complexity and human scale models are the th ree most powerful UDQ mo dels for describing a walkable street. A greater number of features from these models ma y be more critical to ensure the desired combinations of features. Several non-validated features we re not included in the walkable street audit, but they are regulated in high numbers in the codes and men tioned frequently by the interview participants. Regulation in the codes suggests th ey may be important and should be considered for a walkable street audit. The discussion lead to the development of several crit eria, listed in the conclusions and recommendations, which may have a bearin g on the potential of the codes to create a walkable urban street.
136 A B C D Figure 5-1. Imageability features. A) Historic buildings, Kentucky Street, Petaluma. B) New buildings, 2nd Street, Petaluma. C) Courtyar d, Kentucky Street, Petaluma. D) Fountain, 2nd Street, Petaluma.
137 A B C D Figure 5-2. Imageability: sidewalk features. A) Distinctive signage, 2nd Street, Petaluma. B) Landscape features 2nd Street, Petaluma. C) Landmar ks, Railroad Avenue, Hercules. D) Outdoor dining, Castro Street, Mountain View.
138 Figure 5-3. Imageability: building detail. A) Facade detail, South Santa Cruz Avenue, Los Gatos. B) Quality construction materials, corner of C Street and 2nd Street, Petaluma. C) Facade details, Monterey Street, Gilroy. A B C
139 Figure 5-4. Complexity features A) Building width, Railroad Avenue, Hercules. B) Outdoor dining, Railroad Avenue, Hercules. C) Number of Buildings, Railroad Avenue, Hercules. D) Building Colors, 2nd Street, Petaluma. A B C D
140 Figure 5-5. Complexity: sidewalk features. A) Outdoor dining, 2nd Street, Petaluma. B) Public art, 2nd Street, Petaluma. C) Public art, H ealdsburg Avenue, Healdsburg. D) Facade patterns, First Street, Livermore. A B C D
141 Figure 5-6. Complexity: building features. A) Awnings, Kentucky Street, Petaluma. B) Theater wall, 2nd Street, Petaluma. C) Awnings, 2nd Street, Petaluma. D) Shade patterns, University Avenue, Palo Alto. A B C D
142 Figure 5-7. Complexity: street feat ures. A) Roof silhoue ttes, First Street, Livermore. B) Parked cars, First Street, Livermore. A B
143 A B C D Figure 5-8. Human Scale features A) Long sight lines, Railroad Avenue, Hercules. B) Average building heights, 2nd Street, Petaluma. C) Small pl anters, Castro Street, Mountain View. D) Facade detail, Monterey Street, Gilroy.
144 A B C D Figure 5-9. Human Scale: sidewalk features. A) Street trees, First Street, Livermore. B) Coordinated street furnishings, Monterey Street, Gilroy. C) Street furnishings, Kentucky Street, Petaluma. D) Pedestri an lights, First Street, Petaluma.
145 Figure 5-10. Enclosure features. A) Building height to street wi dth, view from Pacific Street, Santa Cruz. B) Awnings, 2nd Street, Petaluma. C) Physical safety features, Monterey Street, Gilroy. D) Physical safety features, 2nd Street, Petaluma. A B C D
146 Figure 5-11. Transparency features A) Windows at street level, Kentucky Street, Petaluma. B) Building entrances, 2nd Street, Petaluma. C) Midbloc k passageways, Kentucky Street, Petaluma. A B C
147 CHAPTER 6 CONCLUSIONS AND RECOMMENDATIONS The conclusions highlight a num ber of consid erations that impact the potential of FormBased codes to create a pedestrian -oriented street. To write codes that focus on walkability, it is necessary to put the following procedures in plac e. First, start with a good understanding of the design qualities and features that relate to wa lkability and are relevant to the user. Second, employ a methodology that allows for quantitative m easuring of the features. Third, identify an effective format for design codes that will translate to a desired built form to meet the goal of walkability. The results section of my study focused on a comparative scale of the quantitative design qualities and features suggested as important by a peer-reviewed published street audit (Ewing et al. 2005). The discussion section focused on the re lationship of the regulat ed features in the Form-Based codes to the features in the street audit and the us ers perceptions of the resulting streets. These conclusions and recommendations are drawn from the results and discussion. Study Strategy The central conclusion of m y study is that the FBCs have the potential to create walkable streets when they regulate a sufficient number of features related to walkability. The Phase I question asked if streets create d from the application of F BCs possess the same UDQs and features as walkable historic streets. Results showed: (a) FB C streets have similar UDQs and features as historic walkable streets; (b) the UDQs of imageability, complexity, and human scale are the most important for creating a walkable str eet; and (c) regulating the frequency of features within a defined area is an important criterion for creating a code that produces a walkable street. Phase II was concerned with user preference. The interview questions were designed to learn the most important UDQs for a walkable street from daily users. The results of Phase II showed: (a)
148 The FBC streets are similar-from the users pers pective-to historic wa lkable streets; and (b) the UDQs of imageability, complexity and human scale are also the most important from the users perspective. Phase III examined the role of the codes, and asked if UDQ model features surveyed on the FBC streets were present due to applicati on of the codes. The results showed the codes regulated few of the audit features. However, analys is of the codes revealed that combinations of many features regulated in the codes resulted in the audit features being present on the street. The results generated six conc lusions: (a) The codes should regulate a high number of features that link to the UDQs, particularly the imageability, complexity, and human scale models; (b) the codes must regulate the frequenc y that the feature appear s in a set length of street; (c) the codes shou ld regulate a high total number of features so there is a greater possibility that combinations of some features will produce the desired qual ities; (d) advantages and disadvantages occur using the Ewing et al.(2005) UDQ models as a gene rator of features to be regulated in the codes; (e) a variety of st yles of codes may meet the goal of creating a walkable street; and (f) mo re performance evaluation, focused on optimal numbers and frequency of features is needed. The conclusions revealed several obvious questions that require, for the moment, speculative answers, including: (a) What is th e optimal number of f eatures a code should regulate?; (b) What is the optimal combination of features for each UDQ model?; and (c) What is the optimal frequency of features in a defined area? Other ques tions for consideration include: (a) the ability to use UDQ models developed from high-density urban streets on other types of streets, such as low-density residential streets, and (b) to what degree do cultural differences influence the effectiveness of UDQ models for generating codes.
149 Using Urban Design Quality Models for Code Development The UDQ models appear to provide a solid foundation for writing codes provided they include both the validated and non-validated features that were hypothesized for the UDQ models from the Ewing et al. (2005) study. Th e study originally proposed eight m odels that included legibility, coherence, a nd linkage plus the five models on the audit. The expert panel members in the Ewing et al. study relied on their professional experience, a review of the urban design literature, and a review of the visual assessment literature to design the UDQ models from the list of hypothesized features. The three models of legibility, coherence, and linkage were not included in the final audit. The loss of these mode ls meant that several features, such as street trees and building materials were not on the audit. The features, however, appear frequently in the literature, the codes, and users comments. Th is suggests they are im portant features that should be included in the codes and they were proposed as potential audit features in the discussion chapter. The hypothesized list of validated and non-valida ted features for all eight models appears more useful for code development than the validated features from the five audit models because the hypothesized list provides a greater number of features relevant to the UDQs. One possible disadvantage of using predefined urban design qu alities and features is that location-specific issues may not be addressed under any of the qua lities and related features. Variability in communities may make standardization difficult, and location-specific issues should not be compromised. The UDQs can provide a good referen ce that will serve as a starting point. The community charrette, which is required for F BC development, is intended to help resolve location-specific issues. Another possible problem with us ing a predefined list of featur es is that the focus on the individual features may obscure th e need to consider the entire context of the street. Designers
150 must understand how the features relate to each other and the de sired urban design quality. My study assessed the value of the UDQ models for developing desi gn codes for walkability, but it is difficult to compare and assess the relative value (importance) of each feature in the models. Key features and key feature combinations were not determined by the Ewing et al. study or any other research investigated for my study. Certain feat ures that are included in several UDQ models might be considered more important simply becau se they impact more urban design qualities. Checklist and rating systems can often be controve rsial for what they include and do not include, but attempts to refine them offer more opportu nities for research and practical application. User Perceptions and Urban Design Qualities Research has shown common architectural preferences among the public based on the emotional response of people to the visual quality of their environment. This aesthetic response is described as a favorable emotion based on f eelings of pleasantness or excitement (Ataov, 1998; Nasar, 1994, 1997; Ulrich, 1983). When intervie wing the users of the streets in Petaluma, it was evident their feelings and emotions were a key determinant in their assessment of the visual quality of the streets. Participants had a more favorable response to the details that affected the complexity of the st reet, such as building facade detail s, architectural style, building colors, signage, and street trees. They had a less favorable response towards the functional issues such as parking, pavement texture (a tr ipping hazard), and traffic speed. The participants were also more sensitive to the features of the street perceived to directly impact their businesses, such as the location of benches (Figure 6-1A) that blocked windows, trash can availability, accessibil ity to their shop, and the location of trees in relation to their signs. Given the commonality of their preferences and the participants ability to identify and describe their preferences, their participation wa s very valuable to dete rmine features and design
151 qualities for code development. It is important, ho wever, to consider other groups of users. My study included only business owner interviewees, who may have different preferences from the general user. Some participants commented they no longer noticed several features because of familiarity, while other features continued to be prominent. The variables of familiarity and change in significance over time may also have impli cations for the codes. Features that retain or grow in significance may be more important to include in the c odes, particularly since one goal of the codes is to produce a built environmen t that will endure even as the uses change. Strengths and Weaknesses of Ur b an Design Quality Models Using UDQ models as a basis for development of a street audit or design codes presents some challenges. The strength or weakness of th e UDQ models depends primarily on the ability to identify and count the features in the model on the street, and the ability to describe, illustrate and quantify the feature in written codes. Imageability, Complexity, and Human Scale Models Based on the audit scores, the features of the imageability, complexity, and human scale models were the most important for creating a walkable street; transp arency and enclosure models were less important. The audit features of the imageability, complexity, and human scale models; particularly courtyards, signs, landscap e features, building colors, art pieces, outdoor dining, windows, and street furniture, are notable because they are easier to identify, quantify, describe, and illustrate. These qualities may make them more relevant to Form-Based codes, since the codes regulate through de scription and measurement, and more relevant to an audit, which requires identification and numerical count on the street. Because the FBCs use graphics and images to convey regulated features, it is more likely these features, which are easily depicted, can be regulated with greater ease. For example, the features related to building facad es are easy to identify and count on the street and regulate in the
152 codes. The features also appear obvious and identifiable to the users because all the interview participants cited the historic buildings, the building co lors, and architectura l style (Figure 6-1B) as being important to encourage walking. The vision statements of many codes reflect the desire to have a complex, interesting street environment. The City of Livermore Downtown Specific Plan (City of Livermore, 2004) includes a narrative of their vision, which conveys a sense of complexity and imageability: Broad shady sidewalks, lined by ground-floor shops and rest aurants, offering pleasant distractions each step of the way.Merchant di splay carts, outdoor diners, and parked cars share the street with pedestrians and cars and create a lively scene.New shade trees, large-scale planters, and pedestrian-scale st reet furniture shape an appealing walking experience. Art is a visible presence. (p. 1-1) The literature and comments from the user s reinforce the notion that imageability, complexity, and human scale are important. The concept that imageability is an important quality is supported by the definition for imageability from Ewing et al. ( 2005), they wrote that imageability is the most important quality to street design and is reflected in the composite effect of all the other qualities. Imageability is the quality that makes a place memorable, and it is influenced by variety and complexity in the envi ronment. Complexity, in turn, refers to visual richness and also depends on variety in the buildings and landscape. Features that contribute to imageability and complexity, such as ornamentat ion, material, color, landscape and furniture, also affect user preferences. When used in a coherent, unified way, they are associated with feelings of pleasantness, an im portant indicator of preference (Cullen, 1961; Ewing et al., 2005; Groat, 1989; Hedman, 1984; Smith, 2003; Stamps, 2000). When interview participants were asked what makes a street memorable, their comments included preferences for building facades, such as colors, details, and windows. In response to the question about what encourages people to wa lk, one participant said : The older buildings, the structures are appealing because they are uniq ue, so it has character to it. People like that old
153 feel. Another, when asked if complexity enco urages walking, commented: Details are very important. Color and movement attracts them. Any feature that is associated with more than one model is important because it will affect several UDQs on the street. For example, one feat ure that imageability a nd complexity share is outdoor dining. Although few codes regul ated outdoor dining, every street surveyed had at least a few tables and chairs for dining. On some str eets, tables and chairs were very prominent (Figure 6-1C). One interview participant placed a se t of tables and chairs in front of his business every morning and commented that people used them constantly. The presence and number of courtyards, plazas parks, landscape features, and public art pieces are also imageability and complexity features, which are straightforward and easy to regulate in the codes. These features (Figure 6-1D) are particularly important because they occupy the spaces between the buildings, and they provide for an essential concept of imageability, which is the visual and physical connection from space to space, building to building, and building to street. Plus they give meaning to the space becaus e they are associated with values and ideas important to the community (Cullen, 1961). Nearly half of the interview participants cited courtyards and parks as important to walkabilit y, noting that features such as fountains and art were an important element in the courtyards. In addition to type of features, frequency for a defined distance or leng th of street (which affects numerical count) is an important criterion for a walkable street that is linked to imageability, complexity, and human scale. In addition, it is a standard that is easy to control in the codes and count on the street. As an urban design quality, complexity is not only dependent on the number and variety of featur es, but also the number of notic eable differences that the user experiences over time, which relates to frequency. Time is related to distance walked and a high
154 number of differences within a time frame will hold the interest of the user and is more desirable for a walkable street (Ewing et al., 2005; Rapoport, 1990). The assertion that imageability, complexit y, and human scale are the most important qualities has implications for the types of features that are regulated in the codes. The relative importance of the models to walkability also helps to determine the relevance of the models to the codes, as expressed in the conclusion; the codes should regulat e a high number of features that link to the UDQs, particularly the imag eability, complexity, and human scale models. Enclosure and Transparency Models The features of UDQ models of enclosure a nd transparency were found to be the least descriptive of a walkable street In contrast to the imageabili ty, complexity, and human scale features, it is more difficult to describe and qua ntify sight lines, street wall, visible sky, and active uses, making it more complicat ed to incorporate in the code s and difficult to recognize and record in the street audit. Some aspects of the features in the models might explain why they were lower in the stratification of the audit mode ls and how this might impact regulation in the codes. The primary issue with the features in th ese models is the ability to accurately quantify and describe features that ar e not physical objects in themselves, but are created by other physical objects. Attempting to regulate features that are not physical objects is related to three important concepts for quantitative measurements of design features ; (a) the ability to describe and quantify the design feature, (b) the ability to link it to a design quality, and (3) the ability to specify a method to measure the frequency of occu rrence of that feature in a defined area (Ewing et al., 2005; Giles-Corti et al ., 2003; Smith, 2003; Southworth, 2005; Stamps, 2000; Zacharias, 2001).
155 Examples from the transparency and enclosure m odels of features that are less well defined include sight lines and proportion of sky, the pr oportion of street wall, and the proportion of active uses. Although the Ewing et al. study (2005) showed high inte r-rater reliability for these features and the audit field manua l gives explicit, detailed instru ctions for identifying features and estimating proportions, a greater possibility continues to exist for individual judgments. Some of the features are more difficult to directly regulate in the codes. For instance, it is not easy to specify in the codes the proportion of s ky or number of long sight lines on a street. The codes can, however, regulate features, such as building height, awnings, street width, sidewalk width, street trees, and other ver tical elements, that define and enclose the street and affect proportion of sky and sight lines (Ashihara, 1970; Ewing et al., 2005; Hedman, 1984; Jacobs, 1993). Codes can also regulate enclosure and transp arency features thr ough narratives that provide statements of intent or descriptions of the desired experience. Some narratives simply state the reason for the regulation, or they can include a detailed description of how features should be arranged or combined. For example, some of the codes encourage view corridors, which affect long sight lines and proportion of sk y, when they have outstanding natural features or historic features significant to the identity of the area (Figure 6-2B ). An example of a statement of intents is in the Pasadena Central District Specific Plan (City of Pasadena, 2004), the Public Realm Design Guide lines for Community Character lists Guideline CC 4: Protect View Corridors. The rationale for the regulation is described as follows: Downtown offers a number of high-quality views and vistas, in particular, prominent views of the San Gabriel Mountains and City Hall. These views distinguish Pasadena from other cities in the region, and or ient residents and visitors alike to their location in the city. A strong Downtown identity depends upon the preservation and enhancement of these special views and view corridors. (p. 132)
156 Recommendations in the Pasadena code incl ude framing important views through heights and location of buildings and looking for oppor tunities to open new views of landmarks, buildings, and features. An example of a description of a desired experience includes one from the City of Livermore to regulate proportion of street wall. While many of the codes regulate the street wall through the use of standard build-to-lines, setb ack restrictions, building widths, and facade treatments, the Livermore codes also explain how to combine features to address continuity of the street wall. The City of Livermore Downtown Specific Plan Design Standards and Guidelines (City of Livermore, 2004) regulates the hor izontal mass of buildi ngs (Figure 6-2A), along the street by describing the treatment of the street wall: Building Wall: While the majority of the building is required to be built to the property line, portions of the building may recede fr om the public right-of-way. The building wall may be varied along the front setback line at key locations, i.e. recessing the storefront entrance, or creating a niche for a resident ial entrance. From one faade to the next, combine a change in depth or horizontal plane with a change in material and character. Changes in facade material or color should be associated with a change in plane or separated by a pilaster. (p. 6-9) Some features are more easily regulated thr ough both a narrative that explains the purpose of the regulation and extensive descriptions of details. One feature; proportion of windows at street level, is shared by the transparency a nd human scale models, but is most critical for transparency. Windows at the street level are re gulated in 90% of the codes, and many have extensive descriptions of windows as features. These descriptions cite transparency as critical at the street level because windows extend the indoors link the public and private spaces, give a sense of security, and provide visual interest (Curran, 1983; Ew ing et al., 2005; Jacobs, 1993). A narrative that describes the importan ce of windows is included in the Pasadena Central District Specific Plan (City of Pasadena, 2004) Private Realm Design Guidelines; Building Design Guideline BD 4: Activate the Street Edge. The inte nt of the guideline is described as follows:
157 Accommodating public use at the ground floor is critical to a socially and visually stimulating Downtown, and stre et level facades offer the gr eatest opportunity to support pedestrian activity. Multiple st orefronts, shop entrances, and activities enlive n the street, sustain attention, and provide a safe pedestrian environmen t. Generous windows placed at the ground floor give people inside knowledge of those on the street, and the people on the street gain an awareness of the activity inside. This phenomenon is commonly referred to as eyes on the street, and supports an active day and night st reet environment. (p. 155) Recommendations include promoting transparen cy by making the uses readily discernable to the passerby through the use of transparen t glass (Figure 6-2C). Many participants commented on windows. One interviewee mentioned window displays: Weve got the bookstore, and their windows are always doing some sort of feature on artwork from one of the schools and that definitely create s that kind of spirit where people are walking by, they stop, they look at the window. The enclosure and transparency models in pa rticular demonstrate how an assortment or combination of details or features must be regu lated in a code to result in the desired design quality or feature on the street. Th ese models also show how narrativ es or descriptions of intent can help to clarify the role of some of the f eatures in producing the de sired quality. Descriptive narratives can include one or all of the following: the desired user experience, the rationale or intent for the regulation, a desc ription of how the features rela te to and create the urban design quality, and recommendations for implementing the features. Linking a feature to the intent, the urban design quality, and the us er experience makes it easier for the person using the code to understand the relationship of the feature to the design quality, the context, and the user. Strengths and Weaknesses of Form-Based Codes The conclusions highlight a num ber of possible strengths and weaknesses in the format and content of the codes. The number, types, and co mbinations of regulated features are important, which is reflected in the format and style in wh ich the code is written. All of these issues may have implications for the flexibility and transferab ility of the code format to a variety of street
158 conditions and different t ypes of development. The types of f eatures regulated and the described intent would probably have a greater impact on th e consideration of cultural differences in the codes. Regulated Features The results showed that codes that regulate a high number of features in each model and a high total number of features had a higher score on the street audit. These codes are also more likely to create the combinations that produce th e desired UDQs, particularly in the key qualities of imageability, complexity, and human scale. Th e discussion of the results demonstrated that many combinations of features ar e regulated in the codes that produced the audit features. This plus the fact that the codes with the highest num ber of regulated features had the highest audit scores lead to the conclusion th at the codes should regulate a high total number of features for a given street length. Several unknowns are relevant to these conclusions; some can be estimated from the data that were gathered in the street audits, and others can be estimated from the discussion comparisons. Very few codes made a specific statement describing a particular key feature or the ideal combination and number of key features, or the de sired frequency of features in a set distance. The Downtown Gilroy Specific Plan (City of Gilroy, 2005) noted on key feature: The addition of street trees alone in many cases can be the single biggest improvement to revitalizing a community; it is the number one improvement priority for the Downtown (p. 104). The literature describes trees as one of the best downtown urban design investments and suggests that the addition of street trees is mo st likely the most cost-effective feature for the biggest impact for a street (Burden, 2006; Paumier et al. 1988).
159 The ideal number of features, combination of features, and optimum frequency of features are unknown. Again, the Downtown Gilroy Specific Plan (City of Gilroy, 2005), did specify a minimum number of benches, planters, trees, an d chairs for every 200 square feet along the street; however, most codes do not specify a combination of type, number and distance. Although the ideal combinations of features are not noted in the c odes, some features emerged as super-features in my study based on the frequenc y that they were regulated in the codes and cited by the interview participants. These super-f eatures might be considered to be the minimal combination of features needed for one block (2 00-300 feet) of a walkable street (one side). Many of the features are associated with the bu ilding faade. The number in parenthesis for some of the features is the estimate d optimal frequency based on the average frequency recorded in the street audits. The features include: windows, architectural detail, awnings, building materials, roof silhouette, entrances (10 doors), signs (10 signs), colors (6 basic colors), and building widths (30-45 feet). Features associated with th e sidewalk zone include: courtyards and plazas (2), planters (7), street trees (10), street furniture (20 pieces, including 4 benches, 6 trash cans, and 10 pedestrian lights), outdoor dining (15 tables), public art (2 to 3 pieces), and parked cars. Flexibility of Form-Based Codes Other questions, which require some speculation, re late to the use of F BCs in a variety of different conditions or street type s. The flexibility of the codes depends primarily on the style of the code, which may affect the ab ility to transfer the UDQ models and FBC format to other types of streets, such as resi dential streets. Cultural differences in the evaluation of walkable streets may also affect the ability to use UDQ models when writing codes. The codes used for my study were written in many different styles. However the format of the codes, which maintains the core function of the codes, remained the same for each code
160 reviewed. All the codes included a regulating plan, building form standards, and architectural and public space/street standards; some of the codes included landscape standards. The difference in the codes is the style in which the standards are written. Some are very prescriptive and others rely on more general descri ptions. A comparative example is the Central Petaluma Specific Plan (City of Petaluma, 2003) and the Downtown Specific Plan for the City of Livermore (City of Livermore, 2004). Streets from bot h cities were audited and they had the same stratification of UDQs, but the scores on th e audit varied somewhat. The FBC street in Livermore had the highest scores in most of the m odels, and the street in Petaluma had scores in the middle of the range. The styles of the code s, however, are striking ly different, and it is tempting to attribute the difference in the scores to the difference in the code style-but this would only be speculation. For example, the Livermore Downtown Specific Plan (City of Livermore, 2004) uses detailed descriptions, with each chapter includin g a narrative for different types of buildings. Chapter 6, Design Standards and Guidelines for Commercial and Mixed-Use Buildings described the architectural style for commer cial and mixeduse buildings as follows: New structures should be identifiable as L ivermore, based on its most integral design styles and continuing its best traditions. They should be based on the same fundamental composition of the existing buildings in Live rmores historic comm ercial Core, with a storefront base separated from the upper stories of the building, and incorporate characteristics commonly found in Downtown, su ch as symmetrical or near symmetrical facades, classical proportioning with a clearly defined base ; detailing and ornamental relief; and simple overall form. (p. 6-16) The code then includes detailed standards a nd guidelines for each element of the building facade, including material types, the base, f acade elements, windows, doors, roofs, and color. The standards for the commercial and mixed-us e buildings alone occupy eight pages of the codes.
161 By contrast, the Petaluma codes divide the code district into areas that constitute a street corridor. The codes describe (in one page for eac h area) the existing build ing patterns for that street (including several photos of the ex isting conditions) and the recommended design approach. The Architectural Guidelines in th e Central Petaluma Speci fic Plan, Appendix B, described the existing pattern of the area along the Petaluma Rive r as industrial, with simple warehouses and processing structures with gabled roofs, construc ted of wood, brick, and metal. The recommended design approach reads as follows: Redevelopment, infill, and adaptive re-use in th is area should adopt th e existing patterns of simple building forms, industrial materials a nd utilitarian detailing. The Dairymans and Hunt and Behrens structures have alr eady introduced complex and random window patterns and angular forms to the area which co uld be adopted and elaborated to create unique architectural so lutions. (p. 7) The codes took very different approaches to standard-writing, some rely more on the interpretation of the professiona l designer and some giving exact parameters. The end result was that both produced walkable streets (figures 62D and 6-2E). The primary difference between the streets was the degree of complexity, which was affected by amount of detail and elements on the buildings and on the sidewalk. Transferability of Form-Based Code Format The ability to transfer the UDQ models and the typical code format to FBCs for other types of streets will depend primarily on the goals a nd objectives of the codes. The UDQ models are appropriate for other types of streets, such as low density residential streets, because the design qualities can be applied to many conditions. For example, imageability and complexity may still be important for a residential str eet, but the types, numbers, and frequency of the features, which are important for the street, may be different. It is also likely that the stratification of the UDQs will be different for residential streets, and the emphasis may be placed on different models. Although imageability continues to be relevant, human scale and enclosure may be more
162 important for than complexity for the activities that take place on a residential street. The format of the FBCs is flexible enough that they can be written to fit many conditions. For instance, the codes may have to include an additional zone for the front yard. This may require new features in each UDQ model that are more specific to a fron t yard, such as plant material, mailboxes, driveways, and parked cars. However, the basic concepts, such as the ability to describe and measure the feature, remain the same. Cultural Considerations Several difficulties arise with trying to determine the influence of culture on perceptual qualities as they relate to walkability. One difficu lty is the definition of a street, which varies with cultures. In some cultures, street may be difficult to define morphologically and in others it is difficult to define by function. The common notion of a street in di fferent cultures may not be adequate to define the setting that is necessa ry for code development. Because the uses of the street--those activities that take place in the stre et--vary widely, the rules of appropriate behavior will have a bearing on the form of the built environment. Studies by Rapoport (1991) have shown that ev en a high variety of characteristics and pedestrian activities can be described in two cat egories: dynamic pedestrian behavior and static pedestrian behavior. The dynamic pedestrian behavior, which cons ists primarily of walking, is constant in nature and not highly affected by culture. Culture will typically influence the acceptability of walking, who walks with whom, and the pace, but not the reason for walking. However, static pedestrian beha vior, which includes other activit ies, such as sitting, eating, and playing in the street, does vary greatly by culture and will have a greater influence on the use of the street.
163 Rapport (1991) gives the comparison of highly public streets and semi-private streets in India. In the public streets a gr eat variety of people are engaged in many different activities such as walking, sleeping, cooking, eating, doing laundry, and getting a haircut. On the semi-private streets in high status areas, wh ere only residents have access, thes e activities, with the exception of walking, are confined to the buildings. This is a reflection of the diffe rences in the traditions of the indigenous and colonial I ndia, with the streets in high st atus areas being comparable to streets in Britain and the United States. Another cultural issue that relates to walking is the visual aspect of the street. Studies by Rapoport (1991) also showed that the visual characteristics of the street did not affect walking behavior among cultures. But other characteristics that affect di fferent senses, such as noise, smells, and movement, did affect cultural prefer ences for walking and other activities. Because my study focused on walking (dynamic pedestrian be havior) as it relates to the visual quality of the street, cultural differences were not considered in the assessment of the codes. Rapoport (1991) said that the most supportive environment for walking for many cultures is a perceptually complex environment with high levels of inte rest. The importance of a complex environment supports the use and the value of the UDQs of comp lexity and imageability to assess a street for walking. Summary and Recommendations The results and conclusions of m y study have general application in several fields, particularly for planners and de signers, who are writing more c odes based on aesthetics and form to help communities make their towns more walkable. Information from my study provides a basis for code development for planners and a re ference for walkable street design for landscape architects and architects. Reco mmendations for the developmen t and use of codes include:
164 Codes should strive to regulate a high number of features an d control the frequency of the features within a designat ed length of the street. The majority of the features that the code s regulate should be linked to the UDQs of imageability, complexity, and human scale. The less precise features of the UDQs can be indirectly regulated by regulating combinations of more definable features th at together create the desired feature. Codes should include descriptive narratives to show how combinations of features relate and work together to create a pa rticular design feature or quality. Codes should also use narratives to describe the desired experience of the user. Narratives may help the designer apply the code more successfully. Codes should use illustra tive narratives to descri be the intent or rati onale for a guideline. Narratives may give the designer a better unde rstanding of the context and improve the administration of the code. Codes can demonstrate the overall effect of cluste rs of features by linki ng features to zones on the street, such as the building facade, sidewalk, and street. The codes should be most prescriptive with building materials and bulk provisions for the faade zone, street furniture in the sidewalk zone, and spatial dimensions for both the sidewalk and street zones. They can be more flexible on the type of building details and ornamentation. Codes should use a format that allows for the best interpretation and regulation of the UDQs and features that are most relevant to their stated goals and objectives. The results show that Form-Based codes are a planning tool that communities can use with reasonable assurance to meet their goals for a more walkable community. The results from my study may also be useful for writing zoning and pl anning laws and legal policy for the regulation of aesthetics or physical ch aracter in a community. Several contributions have been made to the body of knowledge in the design and environmental psychology fields. Ewing et al. (2 005) developed the walkable street audit and made it available to researchers for further testing and evaluation. Using the audit as the basis for my study provided the opportunity to further investigate the urban design qualities and features for a walkable urban street. It was discovered cert ain qualities and features may be more or less
165 important for describing a walkable street. Qualities that appear more important for predicting a walkable street include imageability, complexity, and human scale, and those that appear less important include enclosure and transparency. W ithin the qualities, important features include: building details, materials, color and size, windo ws, street trees, street furniture, landscaping, parked cars, and street and sidewalk dimensions My study also suggests that the concept--that physical design features related to walkability can be quantified, described and interpreted to create a desired outcome-is a reasonable concept. Tables of Recommended Features by Zones Tables 6-1 to 6-4 list the urban design features that are r ecommended to be included in Form-Based codes or used by designers in the development of walkable streets. Each table addresses a different area or z one in the street. The features are also grouped, in order of importance based on frequency of regulation in th e codes and frequency of citation by users, under the UDQs that they most influence. Th e grouping is intended to help the writers and designers choose features based on the urban desi gn quality that they influence. The tables include: the building facade zone, si dewalk and public space zone, street zone, and landscaping.
166 Table 6-1. Building faade zone Recommended features to regulate for building facades Imageability historic architecture vernacular architecture building type (esp. landmarks) architectural style facade composition (detailing) ornamental relief (moldings, trim, medallions) building colors quality building materials roof types, styles building signs, painted signs cornice, parapet with cornice cap proportioning Complexity pilasters bulkheads parapets turrets, towers light fixtures upper story setbacks downspouts and scuppers patterns of moldings, trim, medallions patterns of building entrances window placement patterns building change in depth of plane individual roofs at storefronts marquees, sign bands metal downspouts and scuppers Human Scale exposed rafters and beams decorative panels maximum and minimum building heights maximum and minimum building widths appurtenances beyond height limit Enclosure building proportions front porches, stoops cloth/canvas awnings, overheads colonnades arcades balconies Transparency transparent glass continuous street wall percent fenestration on the facade window proportions and size window placement patterns storefront window shapes, display space transom windows bay windows space between buildings spacing of entryways
167 Table 6-2. Sidewalk and public space zone Recommended features to regulate for sidewalk and public space zones Imageability street trees public art fountains materials, locations for signs small planters raised planters in ground planters landmarks Complexity textured sidewalk murals mosaics bus shelters kiosks manhole covers stormwater grates tree grates gateway features materials, locations for signs public art fountains murals mosaics Human Scale small planters textured sidewalk paving patterns tables, chairs, and umbrellas bus shelters kiosks drinking fountain infrastructure/utilities parking meters mailboxes street trees street furniture pedestrian lights, street lights plazas parks courtyards Enclosure bike racks trash receptacles bollards banner poles, banners, flags bus shelters, shade structures kiosks drinking fountain mailboxes curb extensions crosswalks newspaper racks street trees garden walls fences courtyard entrances sidewalk width Transparency width of sidewalk clear zone setbacks, build-to-lines side setbacks upper story setbacks lot areas scale and mass to match existing buildings maximum and minimum lot widths plazas parks courtyards, courtyard entrances garden walls fences maximum and minimum building widths midblock passageways
168 Table 6-3. Street zone Recommended features to regulate for street zone Imageability traffic lights parked cars traffic speed pavement markings Complexity textured street paving materials parked cars parking bay types and dimensions Human Scale curb cuts traffic speed bicycle lanes parking structures street width median width trees in landscaped median parallel and diagonal parking Enclosure pedestrian refuge islands ROW width crosswalk width traffic lights terminated vistas street width trees in landscaped median parallel and diagonal parking pedestrian refuge islands Transparency median width ROW width traffic lights curb extensions street connections to elsewhere driveway approaches alleyways marked crosswalks ROW width
169 Table 6-4. Landscaping Recommended features to regulate for landscaping Imageability street trees (spacing and type) trees in wells/landscaped beds trees in planters major landscape features Complexity plant types terminated vistas tree grates landscaped median plant types terminated vistas major landscape features Human Scale minimum sizes for planters minimum number of trees in a public space plant size street trees (spacing and type) trees in wells/landscaped beds Enclosure trees in planters proportion of sidewalk shaded landscape buffer width pedestrian refuge islands street trees (spacing and type) trees in wells/landscaped beds trees in planters landscape buffer width trees in planters proportion sidewalk shaded Transparency street trees (spacing and type) terminated vistas major landscape features plant size
170 A B C D Figure 6-1. Urban design qualities: sidewalk features. A) Stor efront bench, Kentucky Street, Petaluma. B) Building facade, First Street, Livermore. C) Outdoor dining, Healdsburg Avenue, Healdsburg. D) Courtyard, Castro Street, Mountain View.
171 Figure 6-2. Urban design qualities: street features. A) Continuous street wall, First Street, Livermore. B) Long sight line, South Santa Cruz Avenue, Los Gatos. C) Shop windows, University Avenue, Palo A lto. D) Complexity of street, 2nd Street, Petaluma. E) Complexity of street, First Street, Livermore A C B D E
172 CHAPTER 7 FUTURE WORK The exploratory nature of m y study leaves so me questions about the use of Form-Based codes to create walkable urban streets unans wered. However, it does provide a structure for future studies and reasonable assurance that Fo rm-Based codes are a zoning and planning tool with a realistic potentia l to create an enhanced pedestrian-oriented environment. My study is only the beginning of what could be many studies of FBCs as they relate to walkable streets. Study Limitations The relative newness of FBCs was a lim iting factor in this study. Very few communities have written FBCs and even fewer have adopted and implemented the codes. Most of the codes, which may be adopted in the next few years, will still take several years to be implemented, and so this time element provides an excellent opportun ity for before and afte r long-term research. Cities that implement FBCs often do so in an area with distinct boundaries that make a limited and well-defined study area. The changes made to the area are usually very dramatic, making them easy to recognize, delineate, measure, and qua ntify--again, an ideal condition for research. The FBC streets surveyed in my study were very new. One had small areas still under construction and others had obvious signs of newness including bu ildings that were not fully occupied by the intended users and small street trees that were barely visible in the landscape. This newness was a factor in the measurement of some of the audit features, for example, long sight lines were affected by lack of a tree canopy. The interviews that were done with the users of the streets were limited to one community and two streets. It would be helpful to have different perspectives from people in other communities as each of the FBC streets and the historic streets had different qualities and characteristics. It would also be beneficial to interview othe r users besides those who have
173 businesses along the street. Several of the intervie w participants noted that they come to the street so often that they do not really notice details anymore. Plus several of the interviewees expressed perspectives that only a business ow ner would have, based on merchandise display and access to their business. A fresh look at the stre et by an infrequent user may offer a different perspective. Some of the FBC streets had features that were not regulated by the codes. Although unregulated features presented the opportunity to note features that should be added to the codes, it was sometimes difficult to ascertain how much influence the codes actually had without carefully separating out the non-code items. Some features may have been, and in some cases were, regulated by other codes. Other features may have been included by the designer, or someone simply took it upon himself to pl ace items in the sidewalk or street. The urban design features used in this study were those hypothesized and validated by the Ewing et al. (2005) study. While the study was a well-designed, ri gorous study by highly respected individuals in the fi eld, it was the only study used to form the foundation of my study. Few studies are available on design features of walkable streets, but others, as they evolve may provide a different perspective on the features that shoul d be considered in analyzing walkability. Urban Design Qualities and Features Recommended f uture work falls into three cat egories: (a) research relating to the urban design features on walkable street s; (b) research relating to walkable street audits; and (c) analysis of Form-Based codes and the streets cr eated through the codes. Three questions related to urban design features incl ude: (a) What are the optimal numbers and combinations of features?; (b) What are the best methods for m easuring and quantifying fe atures?; and (c) What is the best format to codify the features? The optimum number of features within defined boundaries or a set distance is not known. In the FBCs the optimum number is usually related to
174 minimum and maximum distances or percentages, such as maximum building frontage or minimum percent of windows on the ground floor. However, the number of features, such as pedestrian lights, benches, tr ash cans, and trees, is typica lly left to the designer. The ability to measure and quan tify features is a concern that needs further research. The current research limits measurement to counts a nd percentages. Only those features which can be numerically counted or determined by percentage of area or space can be used to determine walkability. Other methods to measure features need to be determined and some features that are too difficult to measure may be essential to a walkable street. So the question remains: How to describe and account for un-measur able features in the audit format? Two other issues with using urban design qualities and models are the overlap of the features and the interconnectedne ss of the models. Street trees, for example, may contribute to several qualities, but the quality in which they are most relevant is difficult to determine. Interconnectedness presents a quandary when trying to place features in the most relevant model, describe the optimum features, or create a hier archy of UDQ models a nd related features to produce an accurate model. Further research is needed on the features to include in a walkab le street audit. The features in the audit were only those vali dated in the Ewing et al. (2005) study. However, the review of FBCs and the comments of the interview particip ants (which gave the average users perspective rather than the expert perspective) point to othe r measurable features th at should be considered. These features could be added to the existing audit and tested using a number of case studies. Form-Based Codes The for mat of FBCs is another area that mer its attention. Some codes are written with a good deal of flexibility and others are very specif ic and detailed in their approach. It would be interesting to study the different formats by aud iting streets developed from each format and
175 comparing audit scores. It is necessary to contin ue to study and monitor streets that are created through the use of FBCs. Many different street sty les will emerge from the use of codes, and some may prove to be more effective than others These studies could be used to fine-tune the writing and development of FBCs. Researchers shoul d study these streets over time to see if the concepts of the codes withstand the test of time a nd become as durable as the historic streets they are modeled after.
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183 BIOGRAPHICAL SKETCH Gail Hansen was born in Fargo, North Dakot a, and m oved with her family shortly afterward to Lake Tahoe, Calif ornia, where she attended prim ary and secondary schools. She graduated with a Bachelor of Arts degree in phys ical education from Calif ornia State University, Sacramento, and a Master of Science degree in exercise physiology from the University of Arizona. She worked in the hea lth and wellness field from 1980 to 1990, first in the Los Angeles area and then for eight years at the Obesity Treatment Center, Sutter Community Hospital, Sacramento. In 1990, she moved to Gainesville, Flor ida, where she graduated with a Master of Landscape Architecture degree in 1994. She worked from 1994 to 2000 for a private landscape architecture firm, Buffington Asso ciates, in Gainesville and then became an adjunct instructor at the University of Florida in the Landscape Architecture Department. While teaching at the university, she began her doctorate degree studies in landscape architect ure in 2004. In January 2008, she accepted an assistant prof essor position in the Environmen tal Horticulture Department at the University of Florida where she is teaching landscape design.