The quality of pedestrian spaces in downtown Denver, Colorado

Material Information

The quality of pedestrian spaces in downtown Denver, Colorado
Young, Andrew Nichols
Publication Date:
Physical Description:
iv, 223 leaves : illustrations, charts, plans ; 28 cm


Subjects / Keywords:
Pedestrian facilities design -- Colorado -- Denver ( lcsh )
Central business districts -- Colorado -- Denver ( lcsh )
Central business districts ( fast )
Pedestrian facilities design ( fast )
Colorado -- Denver ( fast )
bibliography ( marcgt )
theses ( marcgt )
non-fiction ( marcgt )


Includes bibliographical references (leaf 223).
General Note:
Cover title.
General Note:
Submitted in partial fulfillment of the requirements for the degree, Master of Planning and Community Development.
General Note:
Statement of Responsibility:
by Andrew Nichols Young.

Record Information

Source Institution:
University of Colorado Denver
Holding Location:
Auraria Library
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
10935586 ( OCLC )
LD1190.A78 1984 .Y73 ( lcc )

Full Text
MAY 198*f

M. C. Escher 'Still Life and Street'
Phoenix Gallery, San Francisco, California

Very special thanks must be accorded to the author's chief advisor, Professor David R. Hill, whose saintly patience, encouragement and guidance was essential to the project's completion. Tremendous appreciation is also due to Professor Bernie Oones for helping bring the project to a conclusion, from out of a disordered state. The author also wishes to give thanks to Robert Yeager, formerly of The Denver Partnership, Inc., for important guidance and assistance in the development and undertaking of the project.
The Denver Partnership, Inc. provided substantial assistance in materials and tools (maps, printing, printing costs, and the 'assessor's wheel'), and its former and existing staff have been very helpful, particularly Kay L. Liske, Leslie Lee, and lessa Dalton. At the Denver Planning Office, the author was given great assistance by Douglas Goedert of the Central Area Planning Section, and by A. Gordon Appell, who was very encouraging to the author. Galen McFadyen of the Denver Urban Renewal Authority provided useful planning materials and was of great help to the author. Roy Perlmutter and Harriet Moyer of the Urban Design Forum were very encouraging and supportive. Ihanks are also due for Edward Freer, of Syracuse Lawler & Partners, Architects.
Finally, I would like to pay homage to the enormous support of my parents, Allen and Barbara Young, and my immediate family (Sarah, David and Elizabeth), and of my aunt,
Dorothy Stroup. Special appreciation for the inspiration given by my grandfather, Dr. Arthur N. Young, is also offered. Many thanks, too, are due to my friends and colleagues, and to the people who work in downtown Denver, many of whom were helpful in allowing me access to places for photographing the plazas. Ihanks,again, to Dr. Jones for the use of his modern and miraculous typewriter.

ACKNOWLEDGEMENTS ........................................... ii
The Planning Problem (1)-- Project Goals and Objectives (2)-- Scope and Limits (3)-- Organization (A)--Methods and Data (6)
CHAPTER 2. LITERATURE REVIEW ............................... 9
Introduction (9)-- William H. Whyte (lO)--Jane Jacobs (15)-- Secondary Authors (20)-- Local Downtown Planning Literature (23)-- Literature Summary (26) --Literature Addendum (27)
CHAPTER 3. THE STANDARDS.....................................29
Introduction (29)-- The Plaza Standards (30)-- The Sidewalk Standards (AO)
CHAPTER A. DENVER'S MAJOR PLAZAS ............................ 5A
Introduction (5A)-- Skyline Park (5A)-- 1500 Skyline (59)-- 1600 Skyline (6A)-- 1700 Skyline (69)-- Mountain Bell Plaza (72)-- Prudential Plaza (79) Colo-
rado National Plaza (82)-- DCPA Galleria (87)--Currigan Plaza (93)-- U.S. Post Office Plaza (99)--Federal Court Plaza (103)-- City Center Plaza (107) Interstate Plaza (112)-- United Bank Plaza (115)--Zeckendorf Plaza (119)-- Great West Life Plaza (126)--Comparative Plaza Evaluation (13)-- Planning for the Plazas (1AA)
CHAPTER 5. DENVER'S SIDEWALK SPACES ....................... 1A8
Introduction (1A8) Analysis of the Sidewalk Spaces (150)-- Planning for the Sidewalk Spaces (172)
CHAPTER 6. CONCLUSION ...................................... 177
Evaluation Summary (177)-- Recommendations Summary (181)-- Summary (187)
APPENDIX 1. THE SURVEY.......................................189
The Plazas (189)-- The Sidewalk Spaces (197)
CLASSIFICATION BY THE STANDARDS ........................ 20A
SELECTED BIBLIOGRAPHY ...................................... 223

1. Pedestrian Spaces Study Area .......................... 5
2. Denver's Major Plazas ................................ 55
3. Arcade in 1500 Skyline.................................57
A. Overhead Photograph, 1500 Skyline ............... 58
5. Descriptive Data and Ratings, 1500 Skyline ........... 59
6. Area of Steps, 1500 Skyline............................60
7. Overhaed Photograph, 1600 Skyline ............... 63
8. Descriptive Data and Ratings, 1600 Skyline ........... 64
9. 1600 Skyline Amphitheatre Area.........................65
10. Overhead Photograph, 1700 Skyline ............... 68
11. Descriptive Data and Ratings, 1700 Skyline ........... 69
12. Waterfall Structure, 1700 Skyline ............... 70
13. Descriptive Data and Ratings, Mountain Bell
14. Overhead Photograph .................................. 73
15. Ramp Area of Mountain Bell Plaza.......................74
16. Overhead Photograph, Prudential Plaza ................ 78
17. Descriptive Data and Ratings, Prudential Plaza ... 79
18. Fountain Area in 16th St. Mall adjacent to
Prudential Plaza ................................... 80
19. Overhead Photograph, Colorado National Plaza .... 83
20. Descriptive Data and Ratings, Colorado National
21. Large Pedestrian Passageway in Colorado
National Plaza ..................................... 85
22. Descriptive Data and Ratings, DCPA Galleria .... 87
23. General View through the DCPA Galleria.................88
24. 14th St. Entry to DCPA Galleria........................89
25. Southwest View from DCPA Galleria......................89
26. Northwest View through DCPA Galleria...................90
27. Descriptive Data and Ratings, Currigan Plaza .... 93
28. Overhead Photograph, Currigan Plaza .................. 94
29. Entry Steps, Currigan Plaza .......................... 95
30. Overhead Photograph, U.S. Post Office Plaza .... 98
31. Descriptive Data and Ratings, U.S. Post Office
32. Small Entry Plaza, U.S. Post Office...................100
33. Descriptive Data and Ratings, Federal Court
34. Overhead Photograph, Federal Court Plaza ............ 104
35. Arcade Seating in Federal Court Plaza ............... 105
36. Descriptive Data and Ratings, City Center
37. Overhead Photograph, City Center Plaza .............. 108
38. Overhead Photograph, Interstate Plaza ............... Ill
39. Descriptive Data and Ratings, Interstate Plaza 112
40. General View, United Bank Plaza ..................... 115
41. Main Corridor, United Bank Plaza......................115
42. Descriptive Data and Ratings, United Bank
i v

43. Fountain Area, United Bank Plaza ..................... 116
44. Arcade on Broadway, United Bank Plaza ................ 117
43. General View, Zeckendorf Plaza ....................... 120
46. Descriptive Data and RAtings, United Bank
47. General View, Great West Life Plaza....................125
48. Descriptive Data and Ratings, Great West Life
49. Correlation of Plaza Size to Concentration
of Seating...........................................131
50. Ratings of the Plazas in the Standard for Sun . . . 134
51. Ratings of the Plazas in the Standard for Use . . . 138
52. Sidewalk Spaces: Numeration of the Spaces ............ 149
53. Rankings of the Sidewalk Spaces by the Stan-
dard of Sidewalk Character ......................... 151
54. Rankings of the Sidewalk Spaces by the Stan-
dard of Small Spaces.................................156
55. Rankings of the Sidewalk Spaces by the Stan-
dard of Land Use Character...........................160
56. Rankings of the Sidewalk Spaces by the Stan-
dard of Diversity....................................165
57. Initial Plaza Survey Form..............................190
58. Completed Survey Form..................................193
59. Completed Sidewalk Survey Form ....................... 198
1. Size and Seating Characteristics of the Plazas . . . 130
2. Choice and Variety Characteristics of the
3. Visibility and Safety Characteristics of the
4. Sun and Enclosure Characteristics of the
5. Centering and Interest Characteristics of the
6. Use Generators, Use and Food Characteristics
of the Plazas........................................137
7. Trees, Plantings, Lawn and Water Characteris-
tics of the Plazas.................................139
8. Overall Design and Surroundings of the Plazas . . . 140
9. Strengths and Weaknesses of the Plazas...........142
10. Plaza Improvement Project Types and their
11. Distribution of the Sidewalk Spaces into the
Performance Classes of the Standards ............. 170
12. Frequency of Recommendation Types and their

INTRODUCTION The Planning Problem
The network of public pedestrian spaces of downtown Denver, because of its high concentration of use, is a major public facility and therefore a significant planning concern. That concern includes making the sidewalks safe and useful, but how they please and interest people also affects the achievement of downtown development goals. Downtown Denver's economic strength and role as a regional center of business, government, culture and society in general can be greatly assisted by an image of beauty, vitality and cohesiveness.
That image is primarily the product of a high level of pedestrian space quality. These spaces, including parks, plazas, arcades, small sitting areas, the Sixteenth Street Mall, and all the sidewalks, strongly influence how attractive, enjoyable and functional the downtown is to its workers, shoppers, residents and visitors. How these spaces add to the desirability of the downtown can be greatly affected by planning programs and policies.
Successful pedestrian spaces depend on specific details which can make walking and spending time in the downtown generally more of a pleasure than something to avoid. It is vital to determine what these specifics are, and to know to what extent and where they are manifested in downtown Denver. What the strengths and weaknesses of the spaces are, individually and collectively, is essential knowledge for deciding which types of planning responses should be considered and what priority should be given to each. Such a detailed evaluation of each space, and of the whole network, is presently

unavailable.* As a direct result, there is no substantive foundation for making planning decisions to insure that the best possible pedestrian spaces system is developed as part of Denver's downtown.
Project Goals and Objectives
This project addresses the need for an informational background and foundation for making planning decisions regarding the pedestrian spaces of downtown Denver. Firstly, it establishes what the special qualities, details and general characteristics are of a model urban pedestrian environment. Secondly, it measures how these features are manifested in downtown Denver. Finally, it suggests what physical improve-
ments to the pedestrian spaces would be most effective for the development of a cohesive, attractive and functional network of pedestrian spaces.
In achieving the first goal, of presenting an ideal system of public open spaces and sidewalk environments, two objectives are sought after: first, establishing pedestrian area planning goals; and second, providing standards by which the existing system can be judged. These goals and standards are complex, and involve special qualities that make plazas and sidewalk spaces unique and valuable features of a downtown. By examining how these areas rank against the standards, a complete description and evaluation is obtained. The final objective is to recommend improvements that will produce a good pedestrian spaces network for downtown Denver. These recommendations will be made in terms of raising the quality of the spaces, such that the standards are met, or nearly met,
In November of 1983, The Denver Partnership, Inc., published the reports of the "Downtown Denver Public Spaces Project," after the author of this thesis had completed most of the work presented here. A brief review of these reports, and their implications for this project, is presented in an Addendum to chapter two, the literature review.

in all the plazas and sidewalk spaces. Priorities for the types of improvements are also established, and these are the final product of the project. They are intended to set the
stage for research to find appropriate planning tools and strategies for implementation, and for the development of alternative plans.
Scope and Limits
The project does not include a complete plan, but presents some of the major components of a plan, or the substance of these components. The goals and objectives, the data base, and the general recommendations are established, but it does not provide alternative plans or implementation strategies.
The thesis examines the physical environment of downtown as experienced by the pedestrian, and how specific qualities and characteristics of that environment perform particular functions. The seating, amenities, special features, and surroundings of plazas, and the street furniture, landscaping, building facades, and types of land uses along the sidewalks are examples of influences on the pedestrian environment which this project will examine. Activities of people within the spaces, such as vendors, street performers and special plaza events, or the numbers of people using the plazas and sidewalks, are not dealt with in detail in this project. Also largely unexamined are the many planning and other governmental policies which now, or potentially could, direct the character of pedestrian areas.
This thesis assumes that how people do or do not find satisfaction from plazas and urban sidewalks is consistent from city to city. In general is assumes that an attractive and functional space will be met with clear approval by most people, and that likewise people will dislike a place which ignores their preferences, or feel indifferent about a place that fails to attract them. Hence this project leaves to others the
social analysis of the particular people who use downtown Denver and its pedestrian spaces, relying instead on the con-

elusions provided by the literature on the relation of people to urban environments in American downtowns.
A limit of geographical terrain is imposed, which excludes areas outside the downtown core because of their much lower density of activity. The study area, shown in figure 1, was chosen to examine the most active areas of the downtown, between Fifteenth Street and Eighteenth Street on the southwest and northeast, respectively, Lincoln Street and Colfax Avenue on the east and south, and Arapahoe Street on the northwest. While there is a great deal of dense commercial activity recently developed northwest of Arapahoe Street, the development pattern is noticeably different. In addition, because of the detail in which individual spaces are examined in this project, it was determined that some limits to the area covered should be established. Exceptions to the general area limitations include the Denver Center for the Performing Arts on Fourteenth Street, and the Federal Center, which extends to Twentieth Street.
The approach taken in the project is to establish general principles and theories of how certain elements contribute to the quality of pedestrian spaces, and in turn to define what and where such elements are present or absent in downtown Denver. Finally, it provides recommendations for a planning program to develop new elements where they are needed. The need for the project, its goals, scope and structure are introduced in chapter one. In chapter two, the literature review, the general concepts of what elements successful pedestrian spaces require are presented, as well as concepts of what such areas can accomplish if certain features are present. Chapter three presents the standards by which the pedestrian spaces of downtown Denver will be measured, which are adapted directly from the literature. The fourth chapter deals with the major plazas in the downtown, discussing their performance against the standards, and providing recommendations on the basis

Pedestrian Spaces
Study Area

of that analysis. The sidewalk environments are evaluated separately in the following chapter, also with recommendations for physical improvements. Chapter six concludes the project with final recommendations for pedestrian area planning priorities. The appendix contains the full compilation of data about the sidewalk spaces, and a discussion of the author's survey of the downtown.
Methods and Data
The evaluation of downtown Denver's pedestrian spaces that the author seeks to accomplish has an overall method of determining first what physical elements will affect the satisfaction of people who use the downtown, and to then establish where and to what extent those elements exist in the study area. The first step is achieved by obtaining from the literature an understanding of how and why pedestrian spaces fail or succeed. This understanding and knowledge is taken from the authors William H. Whyte. Dane Jacobs and others, as well as from the literature of agencies involved with the planning of downtown Denver. Their observations and conclusions about what pedestrian spaces can achieve, given certain design guali-ties and other conditions which planners can control, are the direct sources of the standards by which the author measures the guality of downtown Denver's pedestrian spaces. In this manner, the standards that the authors and sources have provided are brought to bear on the present condition of the spaces. Chapter two examines the sources, and chapter three reveals how their knowledge is transformed into standards for use as a means for surveying and evaluating the pedestrian spaces in the study area.
The remainder of the project deals with the rankings of the plazas and the sidewalk spaces against the standards, as determined in the survey. The survey methods are explained in detail in the appendix, and the results of the survey are given in chapters four and five. The rankings of the spaces,

such as the degree of enclosure in a particular plaza, are used as data for the purpose of the project to evaluate the quality of pedestrian spaces and establish planning priorities. The data in chapter four is presented first in a series of discussions of the individual plazas, and later in the form of tables accompanying an analysis of the plazas as a group. Recommen-
dations for each plaza are developed on the basis of its ranking against the standards, and on additional analysis. The group of recommendations are then synthesized into final recommendations and plaza improvement priorities.
The purely descriptive data regarding the sidewalk spaces are contained in the appendix, due to the large number of tables in which they are recorded. But the rankings of the sidewalk
spaces at the actual standards are provided in chapter five as the subject of analysis, which is directed at groups of spaces and patterns among them, rather than at individual spaces. Recommendations for the spaces are developed directly out of this analysis and based on the performance of the sidewalks against the standards.
The methods employed in rating the success or failure of the plazas is distinctly different from that applied to the sidewalk spaces. Many of the plaza standards are abstract and complex, and are estimated to be met or unmet according to the observation of the plaza by the author in the survey.
For example, how a plaza encourages people-watching, or how the surrounding land uses contribute by supplying people to watch, are measured by general observation, rather than by strictly quantitative, 'statistical' methods. The validity of this method is largely insured by a thorough discussion of the criteria used in each of the plaza standards. The sidewalk space standards, however, are simpler and based on combinations of actual quantities or concentrations of specific elements. Both methods have certain flaws which will be discussed in the appropriate chapter, but they serve the author's purpose is showing the gap between the ideal (as defined by the standards) and the existing situation. The resulting evalu-

ation is believed to be thorough enough to identify the planning objectives of a physical improvement plan.

William H. Whyte's 1980 book, The Social Life of Small Urban Spaces (Whyte, 1980) is the primary basis of the project's analysis of the downtown plaza spaces. The book presents principles of what urban open spaces require in design and content to make them useful and valuable to the public. Many of the ideas emphasize simple features such as seating, trees, and water, but others draw attention to more complex characteristics which make the difference between a popular, exciting plaza and a dull and lifeless one. Nearly as important as his recommendations are his warnings against specific design flaws which defeat the purpose of public open spaces.
The project's source of criteria for measuring the quality of sidewalk spaces is derived largely from Dane Jacobs' book The Death and Life of Great American Cities (Jacobs, 1961), which in spite of having been written over twenty years ago, remains a powerful analysis of what intensely developed urban districts require in the way of sidewalk characteristics and plaza spaces. She contributes some principles of plaza design
to this project, but her central argument is for land use and development patterns which bring people to plazas and sidewalks at different times for different purposes, in order to extend the usefulness of any space.
Additional, secondary authors add concepts for both sidewalk and plaza spaces, but primarily they present guides for evaluating the downtown's pedestrian spaces as a whole, and how they relate to one another. Harvey M. Rubenstein (R.ubenstein, 1978) identifies several elements which may need
strengthening in a central city area, and provides a means for

analyzing spatial forms. Klaus Uhlig (Uhlig, 1979),
Roberto Brambilla and Gianni Longo (Brambilla and Longo,
1977), in spite of their strongly European background, express some highly universal criteria for how a network of pedestrian spaces and paths should work for a city and its core to achieve both functional and social objectives.
Lastly, CJane G. Brown and Karl Katz (Brown and Katz, in Taylor, 1979), who provide suggestions on the use of land in the demolition- to-new construction interim, are discussed as source of a unique planning strategy.
In the final section of the literature review, the local planning literature on downtown Denver, including plans, reports, guidelines, and special regulations, are examined. This provides generally indigenous criteria and principles which serve to evaluate how the downtown's pedestrian spaces, particularly the sidewalks, serve to attract and interest people. It also highlights the priorities for public open spaces that the various institutions and jurisdictions have from overall 1 pedestrianization' suggested in the Downtown Development Plan (City of Denver Planning Office and Downtown Denver Inc., 1978), to the elevated walkway system of the Skyline Urban Renewal Plan (Denver Urban Renewal Authority, 1967).
William H. Whyte
Whyte's book The Social Life of Small Urban Spaces is described by its author as a study of why some city spaces work and other do not, and of what planners and designers can do based on that knowledge (Whyte, 1980: p. 10). The question arose through Whyte's earlier, extensive filming of people in such spaces, where he found that people were smiling, as a result of being especially pleased with certain places (p. 7). William K. Reilly describes these in his Foreword to the book as "healthy places that people like in cities, places that contribute to happiness, places that can bring out that smile." (p. 7). Reilly adds that the failure to provide such places

of urban pleasure, will effectively drive people out of the city to the suburbs, where they will insulate themselves from the humanity that the city represents (p. 7). Whyte concludes his book by saying that the mere appearance of pleasant spaces gives the city's population a perception of the downtown as a place they want to be in (p. 101). Thus the ultimate meaning of a pedestrian area which works' for Whyte, is that it maintains or develops people's attachment to and appreciation of a downtown area.
Reilly sums up the key principle of the book, that if the place has details and elements which attract people, it will be essentially full of life and free of problems (p. 7). The places should be sociable, Whyte says, with people in groups, people meeting people, and physical gualities that bring those people to the place by conscious intent and decision (p. 17). He finds that "places people like best of all, find least crowded, and most restful are small spaces marked by a high density of people and a very efficient use of space."(p. 101). The key principle of plaza design is to provide seating, so people can actually stop and relax for whatever reason. Seating is more of a determinant of the use of plazas than the size, shape or aesthetics of the plaza or the architecture of the associated building or buildings. Amount of seating determines the number of people who may stop in a plaza, but the quality of the experience may be higher or lower according to the variety of choices given to each person for sun, shade, and relation to elements of special interest or shelter from wind and weather (pp. 27-8). Providing the most choice in seating requires several considerations. A movable chair or bench allows the greatest choice, but if fixed seating is used, it should be a generous ledge or flat bench, wide enough to be sat on from both sides.
Fixed individual seats are too limiting in the possibilities that a bench offers. Rows of benches work well, and the inside corner of two ledges meeting at an angle encourages conversation among a group (pp. 31-5).

Another critical choice to provide is allowing people to sit where they can see and be seen by the main flow of people either on the sidewalk or going in and out of adjacent buildings. In fact, Whyte found a behavior pattern of people choosing the middle or the edge of pedestrian traffic for standing conversations and for sitting on any available ledge. "Circulation and sitting, in sum," he remarks, "are not antithetical but complimentary."(p. 33).
The behavior patterns of people in groups is vital to the success of plazas. A well-used place is attractive to still more people, but there is rarely a feeling of being too crowded, even when all the available seating is taken and some of the users are standing (p. 11). Unique and sometimes bizarre special events and occasions, from public sculptures and concerts to street magicians, musicians, characters and so forth, have the effect of making places friendlier, allowing strangers to behave like casual acguaintances (pp. 94-8).
Food vendors and outdoor cafes and snack bars add another sensory experience, whether one is eating, or merely watching, (p. 30). People-watching is a major, possibly even the major pastime of people in urban plazas. The best form for encouraging this is with a slightly sunken plaza, where a gradual descent can create "several tiers of people looking at people looking at the show."(p. 59). It is as though people were like fine landscapes, panoramas or sculptures -- aesthetic elements in themselves.
Another social phenomenon Whyte feels is strongly affected by design is how 'undesirables' are made harmless and mostly unnoticeable in a space that appeals to and can be used greatly by the general public. But when an architect designs a plaza that discourages anyone from useing it, it actually has the effect of 'welcoming' derelicts and drunks to establish it as their unchallenged territory. Elaborate closed-circuit camera security sytems are far inferior to the security provided by observation by the general public or by an on-site, friendly

plaza 'mayor,' such as a door-man or security guard (pp.60-4).
Beyond physical amenities such as seating, and other street furniture, how a space deals with natural elements is a major factor in its ability to attract people. In order to offer the choice of sun, shade or a mixture, sunlight should fall on the space for a substantial part of the day, thus reguiring some southern exposure. An alternative suggested by Whyte is to exploit the reflection of sunlight by the mirror-like surfaces of modern architecture. Elements of plaza design can deal with the sunlight to provide the various degrees of warmth wanted, according to the season. Small niches and crannies which trap the warmth of the sun by lessening the wind are very desirable in cooler weather. In hot summer weather, total canopies, shade trees, pavillions and glass arcades provide a wide choice of microclimates, the latter two creating combined indoor-outdoor spaces. Flexible elements which stop winter winds but can induce summer breezes are highly desirable, (pp. 42-6).
Other natural elements of importance are directly attached to the plaza. Trees should be ample and relate well to seating areas. Lawns are a form of seating themselves, as well as a landscape element. Water can be very pleasing, but it should be accessible and free to touching, splashing, and even wading. The white noise effect of fountains and waterfalls is soothing and appeals to nearly everyone (pp. 46-8).
Successful spaces are not always the result of careful, attentive or conscious design efforts. What works best can be unintentional accidents which happen to provide a place to sit and watch people, capture the sun's warmth, or grab a person's attention by surprise (p. 12). Spaces with unusual objects, such as hydrants, piping, ledges and walls, and small niches and odds and ends of space can be strengthened with a little effort and made into satisfying urban spaces (pp. 99-100).
Visual access into such spaces may be as valuable an experience for a person as being able to enter it physically.

It is even more important for general plazas to be clearly visible from the sidewalk. Interconnection and juxtaposition of the two, to allow people to enter one or the other with just a few steps is essential. But making that kind of access clear, through strong visual interrelation is egually necessary. The path, if any, into a plaza should be inviting, with only a slight or gradual change in elevation. This is best for handicapped access, but crucial for inviting the general public into the plaza (p. 57, p. 33).
Though Whyte concentrates on plazas, he also makes general statements about how sidewalk spaces should function. The street and its walkways are where all the action in cities begins, and is where every great urban open space starts (p. 54). Plazas, retailing, services, lobbies and activity in general must be seen and be accessible from the sidewalk, not walled off, sunken or elevated out of sight (p. 57). Any environment that rejects the street is a great "declaration of mistrust of the cities."(p. 57).
Such a rejection is characteristic of the modern pattern of downtown development referred to as megastructures, which Whyte strongly criticizes, and in effect defines what to avoid in the development of public pedestrian spaces and general urban design. These projects take the normal activity of the street and place it inside the structure, often one or two floors above or below the street, in an enclosed, controlled environment. With their mix of uses, they attempt and often succeed in creating a self-contained city, entirely separate from the streets, where all the activity of the city is open to the public.
For Whyte, these have no 'sense of place,' meaning that they are typical of airports and suburban malls, and reveal nothing of the actual city it is in, whether an old or new town, in the East or the West, domestic or foreign, or even on terra firma at all. Like a suburban mall, access is achieved mainly by car, and one must walk through rows of

parked cars. Also like shopping malls, they are not a part of the surrounding urban fabric, and fill out entire blocks at a time. For the person on the sidewalk adjacent to the project, there is commonly just a blank wall, and for the store owner on the street, all the people have been drained away into the megastructure. And most commonly, the project's interiors are not entirely public, but rather more exclusive and forebdidding to the casual stroller and sitter not intent on consuming goods and services (pp. 79-89).
Jane Jacobs
Though Whyte concentrates his analysis on the densest commercial cores of downtowns, he starts his book with how fascinating he found ordinary street behavior in just a single block of Harlem, with a high density of residential uses.
There could be found all the clues to what people need in < terms of a street in a lively city district: mixture of uses; street-directed activity; places to sit; and a variety of things to do and see (Whyte, 1980: p. 8). This kind of environment is the specialty of Jane Jacobs, whose book, The Death and Life of Great American Cities primarily examines dense city neighborhoods like Harlem in very large cities, such as New York, Boston, Chicago and San Francisco.
Whyte's reference toa Harlem neighborhood is appropriate, for there is a close correlation between a successful dense city neighborhood and a successful metropolitan downtown district, particularly in the way in which sidewalks function. By this reference to Harlem, Whyte makes an apt acknowledgement of the validity and relevance of Jacob's principles of what makes a pedestrian environment satisfying, whatever the type of district.
TDespite the book's considerable dwelling on the theory of what a city is and what all aspects of it mean for the economic, social and political life of its people, its emphasis is on how the physical details of development in dense urban areas affect people. For Jacobs, the scale at which

the physical environment shapes the amount of pure function or simple enjoyment that people find in a downtown, varies from the entire district to the block face and urban park.
As Whyte concluded, Oacobs also found that what makes a plaza work is how well it is used, not how large or how beautifully it is designed Oacobs, 1961:pp. 89-90). It must get the use of shoppers, strollers, and visitors throughout the day, and serve the diverse elements of a city as "a pleasant joint facility." (p. 101). Comparing Philadelphia's Rittenhouse
and Washington Squares, she noted that the latter is a vacuum in terms of usage for virtually the entire day, enjoyed only by workers from surrounding office towers at lunch time, because there are so few stores, restaurants, apartments, cultural facilities and so forth to attract people into the district at other times in the day. Rittenhouse Square, on the other hand, has all these uses around it, generating plenty of people to enjoy the plaza from morning to late at night, and a sequence of uses and users so intricate that it can be called a kind of 'ballet.' (pp. 96-7). When plazas have this kind of success,
they will be "delightful features of city districts, and grow more beloved and valuable with the years." (p. 89). So, though it is people that make plazas worthwhile, it is the arrangement of downtown and city land uses which make these general use, public open spaces get put to use for more people and more of the time.
But design details of the space may contribute a great deal as well. Jacobs calls her first of four standards 'intri cacy,' by which she means tangible reasons to enter the place, and things to find enjoyment from. These would be, for example, sitting to rest, relax or observe, read, work or think, meet a friend, show off, watch the city from a retreat, find a bit of nature in the city, keep a child occupied, "and almost always to be entertained by the sight of other people." (p. 103) These simple pursuits can be served best by complexity of design such that the form and content of the park demands more than a glance to be comprehended (p. 104). The second principle of

plaza design suggested by Jacobs is that of 'centering,' which requires that there be a focal point to the plaza, serving as a crossroad, a climax, a pausing point, or, best of all, a kind of stage for people (pp. 104-5).
Sunshine constitutes her third standard, but her fourth is one which demands enclosure of the plaza by surrounding buildings, though at a height compatable with the need for adequate sunlight. Plaza enclosure is vital to giving definite shape to it, and showing that it is a special feature and event in the city, "rather than a no-account leftover."
(p. 106). For those peices of land that are in fact left over and are not suitable for commercial development, heavy landscaping is suggested, for ""simply pleasing the eye."(p. 104)
When the plaza's surroundings fail at generating users throughout the day, or not at all, it needs to have 'demand goods,' such as music, theatre, carnivals and other significant and real attractions. Simpler features could include children's play areas, skating rinks or picnic facilities (pp. 107-110) If a plaza has neither the surroundings nor the features to attract the general public, it will find itself regularly occupied by characters from skid row. This will not necessarily
make it a 'crime park,' but it makes it generally distasteful, "because human failure in such undiluted doses is hard to swallow." (p. 99). The only cure for a park with so little going for it, is the development of diverse primary uses, such as housing, retailing and offices, around it at very dense levels.
(p. 110).
The pattern of development and land use organization which makes downtown parks successful also is essential to the character of the sidewalks and street environments. As with parks, sidewalk spaces need uses, not amenities, to bring people to them, and a mixture of work and leisure uses brings people to them throughout the day with differing pursuits (p. 152).
A mixture, too, of building types, ages and conditions will provide important opportunities for small enterprises and activities which have low earning power but function on a less

regular schedule and serve a more diverse cross-section of society (p. 188). This complete pattern of diversity distributes people more evenly in time, and at many points along each block face as well, which does a great deal to create informal monitoring of the streets and fewer opportunities for crime (p. 36).
The economic vitality and functionalism of such a pattern is powerful, but the aesthetic effect that can be derived is perhaps equally so. A district of real diversity can show genuine variety and patterns of content which can become interesting and stimulating to the eye." (p. 226). In contrast, Jacobs finds, a district of homogenous uses has a certain kind of chaos in the weird, contrived, phony and exhibitionist designs that are forced upon it (p p. 22A--6). Creating unity of diverse building facades along a single block face, or in a series of blocks, is the main means for putting an aesthetic order into a downtown district. "On certain streets, any disproportionately large occupant of street frontage is visually a street disintegrator and desolator, although exactly the same kinds of uses, at small scale, do no harm and are indeed an asset." (p. 23A-).
To unify streets, Jacobs argues for limiting by regulation the amount of street frontage permitted to any single enterprise. Street cohesiveness may also be achieved, she says, by the design of amenities, such as trees, awnings, street furniture, and paving patterns to identify specific streets (p. 390).
The density and concentration of activity can harm the street's identity, unity and appeal by being either too high or too low.
An upper limit is reached when a building's base must fill out the majority of a block face, eliminating diversity of building type and age (p. 212).. Uses which require large amounts of land area with very low concentrations of activity, such as parking lots, gas stations, junk yards and unused buildings detract greatly from the appearance and activity of the street, (p. 230). But, says Jacobs, "The worst case possible is no

foundation from the past at all: empty land." (p. 216).
In dealing with the aesthetics of the city, Oacobs exhorts planners to understand that "a city cannot be a work of art." (p. 372). The city, a district, or a block face cannot be an architectural, artistic problem, because there are no single elements of city structure, but only the mutual support of diverse elements, developed independently (pp. 373-6). As stated above, the primary means of transforming the diversity of a city district into a coherent, appealing and attractive scene, is by weaving together the various bits and peices of city environments and activity into a single fabric, continuous and without cuts, tears or holes (p. 390). Emphasis and suggestion are the most suitable ways to clarify and express the inherent order, function and aesthetics of city diversity. Planners and urban designers should seek to ennoble, illuminate and heighten the city's complexity (pp. 373-7).
The gridiron street system of American cities can obscure that order by the visual emphasis on repetition and endlessness, which draws attention away from the foreground of intricate diversity, which becomes contradicted and confused. Reducing these incoherent and unnecessary distant views on many, but not all streets, with visual interruptions, heightens the intensity of the street by enclosure and emphasizes the intimate view. Examples include elevated walkways, buildings that bridge or even block some streets, added streets, and squares, parks and plazas (pp. 378-82). However, there must be some street intensity, diversity and vitality to enclose in the first place. Enclosing places without any structure of substantial diversity, or places which are monotonous, would eliminate even the relief of a view to somewhere else. Furthermore, endless repetition
of enclosure runs counter to the overall need for variety, so some long or even endless views are called for (p. 382).
Landmarks and less intentional eye-catchers, by their distinction from their surroundings, also lend emphasis to a district's variety (pp. 384-8).

Secondary Authors
Harvey M. Rubenstein, in his book on the design of downtown pedestrian malls, Central City Malls (Rubenstein, 1978), makes the point that the image of a central city is based on "shape, color, texture, arrangement, and sensory quality, all of which give the observer clues to its identity and structure." (Ibid.:p. 25). Paths, or pedestrian routes, are identified by Rubenstein as needing their own identities, created by consistent spatial qualities, paving materials, special lighting patterns, planting designs, or types of commercial activity. (Ibid.:pp. 25-6). Beyond those simpler elements of the urban environment, Rubenstein suggests over a dozen form characteristics that could potentially be either measured in an urban area or established as urban design objectives, such as the standards being created in this thesis. These are generally not applied in this project, but they are worthy of brief mention in a rough form: contrast; continuity; sequence; repetition; rhythm; size and scale; shape; proportion; heirarchy; dominance; texture; transparency; direction; similarity; and volumes and enclosures (Ibid.:p. 33).
Of these, the characteristics of enclosure and size and scale, as defined by Rubenstein, are considered as important to the project, as they further define Jacobs' concepts of plaza enclosure and visual interruptions. Enclosure and volumes are defined as the product of base, vertical and overhead planes, created by, respectively, streets (or paths or plazas), building facades, and rooflines (Ibid.). Size and scale quality depends on relative proportions of those planes to one another, and on retaining the interaction of building facades by limiting the general width of open areas to within four times the height of their surrounding buildings.
In addition, an open area should have at least one major dimension of less than 150 to 200 feet, in order to maintain a degree of spatial intimacy (Ibid.: p. 30).
Klaus Uhlig, a German urban designer, observes that a

city's character, history, personality and image are represented in the city's public spaces, and particularly in its main center (Uhlig, 1979: p. 6). A city center's beauty, he continues, is derived from a seguence of dissimilar squares, varying in shape, size, use and design of building facades, but sharing a common characteristic of strong enclosure by surrounding buildings (Ibid.: p. 26). These squares or plazas need to be tied together in an integrated network of pedestrian paths which is both functional and attractive, serving both work and leisure purposes (Ibid.: p. 6). Ideally, the network should link the commercial areas of the downtown with recreational and residential centers around it, as well as the district's own activity centers, its main arterial streets and side streets, public transit stations, and parking areas ( Ibid, p. 10). Distances between major parking areas and the core of the downtown should be filled with activity, interest or amenities (Ibid.: p. 20). Finally, the network should remain on a single level, without frequent shifts in elevation, and except for subway terminals, avoid enclosed underground concourses, instead giving people the light and air of canopies and gallerias for weather protection (Ibid.: pp. 22-8).
Uhlig emphasizes a holistic approach which deals with the entire city and its individual places, for the dual reasons that walking is both a utilitarian means of movement and a highly social activity (Ibid.: p. 6). For these functions, the pedestrian system must mix linear forms and larger areas, where people can linger, relax or be entertained (Ibid.: p. 14). Pedestrian areas must provide a place for excercising one's social behavior and establishing social and public relationships, where the act "of showing oneself, of satisfying one's curiosity, of dawdling along, of self-representation, of communication and of living together on this people's stage, this forum, constitutes the public concept."(Ibid. : p. 6). When these social behavior patterns are made posssible by design accomodations, then the city's character is expressed especially well, through both the people and the physical image of pedes-

trian-oriented amenities and facilities (Ibid.: p. 6).
Such a system of pedestrian spaces is close to the vision of the writing team of Roberto Brambilla and Gianni Longo, also of a European background, who have studied the public space quality of American downtowns in great detail. Their recommendations touch on many components of plaza and sidewalk environments, but are summarized in the suggested design criteria, listed as follows:
1. Functional objectives: access, mobility, maintenance, and services .
2. Social objectives: participation, observation of activities, playing, celebrating, performing and learning.
3. Economic objectives: support of commercial activity.
4. Environmental objectives: development and/or preservation of natural and historic elements. (Brambilla and Longo, 1977: p. 115).
They state that it is critically important for planners to understand how pedestrian area improvements can deal with the multiple problems of a downtown, suggesting building facade improvements as a means of stimulating the economy, besides often preserving historic features (Ibid.: p. 3). When one closes a street to traffic, the view of architectural features and history is greatly opened up, and pedestrian-directed signage, lighting and amenities will emerge of necessity (Ibid.: p. 33). Landscaping, seating and other desirable elements attract people to the place, so the expense becomes cost-effective (Ibid.: p. 35). Simply extending the width of the sidewalk, gives more freedom to the pedestrian, and mor opportunities for a variety of activities and amenities. This freedom, which can be created in both plaza and sidewalk spaces, teaches people new social habits and widens their perception of the value of cities (Ibid.: pp. 39-41).
A regular problem for downtown areas, of the blight and disinterest created by vacant land and surface parking lots which fill the time gap between demolition and new construction, is the special interest of another pair of writers. Bane G. Brown and Karl Katz (Brown and Katz, in Taylor, 1979) observe that such time lapses may run into years, and they suggest in response to this problem a wide variety of temporary uses of

of the land, which can contribute immensely to the quality of the urban environment. These may range in time from days, to weeks, or even years, and consist of simple events such as open air art exhibits, sculpture workshops, flea markets, neighborhood gardens, and nearly anything else one could think of.
The authors suggest that such programming can realize a potential, otherwise missed, for making an empty place into an exciting part of the pedestrian environment (Ibid.: p. 110-11).
Local Downtown Planning Literature The documents, plans and legislation concerned with downtown Denver directly supports several of the principles of how pedestrian areas function given by the foregoing authors, and establish some additional ones. The Downtown Denver Development Plan (City of Denver Planning Office and Downtown Denver, Inc., 1978), stresses concepts, rather than specific design regulations, of land use, building density, transportation and urban design to guide and influence ongoing decisions. The language is thereby similar to many of the authors above, as seen in this quote from the conclusion:
People desire and expect downtown to be more unified in design and function. There is a need to find in downtown a sense of place, urbanity, diversity, and a certain quality of unity. Residents of Denver and the region would like to be able to downtown Denver the stimulation of interesting streets and shops, dramatic new architecture, the richness of older buildings, and inviting urban spaces (Ibid.:"The Need for Collaborative Design")
The plan encourages density, "provided that new building design reinforces a unified pattern of street activity, adds to pedestrian interest, and that transit service keeps pace with the higher numbers of people using the area daily." (Ibid.: "General Development Plan"). "All new buildings and renovations should contribute to street level pedestrian activity and interest." (Ibid.). It suggests redevelopment of sidewalk spaces to higher design standards with greater capacity, and

would judge new development projects by the way they attract, interest and accomodate persons on foot, including through-block walkways and arcades, and elevated walkways. "All downtown parking structures should include retail or commercial space at street level, to maintain continuity of pedestrian interest and activity ."(Ibid.) It recommends that parking structures and traffic arteries be placed primarily around the core to ease traffic congestion, add to building frontage continuity, and eliminate driveways (a source of direct auto/pedes-trian conf1ict) (Ibid ) .
A section of the Plan, entitled "Design and Streetscape, has recommendations concentrated on the development of pedestrian path networks, linking activity centers and surrounding residential neighborhoods, and on general 1 pedestrianization of the core area. Improvements in walkway surfacing, lighting, graphics, seating, trees and plantings are considered essential to pedestrian satisfaction. An earlier effort by Downtown Denver, Inc., by its Design and Environment Committee, was the Downtown Denver Streetscape report (Downtown Denver, Inc., 1977), which argues for improvements to the complete environment of downtown street spaces, from pavements to furnishings, trees and building facades. These elements establish the identity and image of each place and the downtown as a whole by their relative degree of clarity or chaos presented to the pedestrian. The image should be as pleasant and comprehensible in design as the competing suburban commercial and office centers. This is possible by reducing the visual pollution and confusion of public and commercial signage, and by attractive design of the main elements of the 'streetscape 1 (Ibid : section 1.1-2). These elements are lighting, traffic and parking signs and devices, pedestrian assistance amenities, building facades, business signs, and plazas (Ibid.:section 2.1).
This holistic approach to the pedestrian environment is carried on by the Denver Planning Office, in its design guidelines publication for the Sixteenth Street Mall (City~c,f Denver,

Planning Office, 1980), which states that the image of the whole city is the product of street images that are "derived from various combinations of building facades, entrances, signs, sidewalks, raodways and traffic."(Ibid.: p. 3). The design guidelines book is further subtitled to express its emphasis on restoration and new development around the Mall, "for Building Facades, Storefronts, and New Development." Besides the amenities provided by the Mall itself, the success of the district isdependent on "a fine grain of shops, entrances, display windows, restaurants, graphics, and architectural features at street level."(Ibid. : p. 2) Continuous building frontage, when full of variety, and closely directed at the street, provides texture and interest, but with newer projects accupying so much of a block face, it says, the need for detailed control of design is crucial. Furthermore, it is essential to avoid building complexes which cover entire blocks, "each turned inward on itself, providing only blank walls facing the street." (Ibid.). The Mall creates a special 'floor,' it explains, but the 'walls' must match the elegance of the Mall, with careful renovation of older buildings and window dressings and graphics to engage the interest of the pedestrian (Ibid.: p. 8) Briefly, the design guidelines strive to provide or maintain: (1) continuity of retail uses; (2) design integrity of existing buildings' facades; (3) pedestrian interest and appeal by new buildings; and (4-) quality graphic design which relates well to the building and the street .(Ibid. : p. 7). The need for building and retail continuity forbids parking garages, discourages large plazas, and it is recommended that any vacant store window be filled with public information displays. New development should have tower portions, if any, set back from the Mall, but their street, second and third levels built out to it, creating a primary roofline that is consistent with the shorter, historic buildings. Blank walls and reflective glass are considered harmful and inappropriate (Ibid.: pp. 11-16).
These guidelines and principles, however, are translated into only a few actual regulations, as part of a zoning amendment to

the B-5 zone district which affects 125 feet to each side of the Mall right-of-way (Denver City Council, 1981). Most notably, it gives development rights bonuses to developers for including retail at street level with display windows, requires all parking to be underground, and gives a smaller open plaza bonus to developers along the Mall than in the overall B-5 zone. It also permits outdoor retail sales and encourages, also with bonuses, the development of arcades and interior plazas surrounded by store windows (Ibid.: sections a, b, d, e, f and h.).
Another special area of downtown Denver is the Skyline Urban Renewal Plan district, about 30 blocks in area, between the downtown core and lower downtown (about Market Street).
Ihis is in the jurisdiction of the Denver Urban Renewal Authority, which has planning powers to precisely control development, with the intent to renew the area's vitality. Its regulations promote plazas, walkways and arcades, especially when elevated above the street, to "separate pedestrian accomodations from vehicularly-oriented facilities located at grade and subsurface levels." (Denver Urban Renewal Authority, 1967: p. C-A-). It stipulates that plazas are to be "attractively designed for maximum pedestrian utilization." (Ibid.).
Literature Summary
There is a great deal more literature available on the subject of the quality of plazas and sidewalk spaces, but the material taken from these authors and sources is sufficient to establish the most important principles applied in this project.
It covers the particular designs and features that are essential ingredients of open spaces, including elements of function, beauty, interest and social accomodations. The appropriate characteristics of buildings along the sidewalk, and of the street furniture and other amenities in the pedestrian path network, are described in adequate detail. Though there may be other factors which affect the quality and success of these spaces, either not covered by the authors or requiring special

investigation of specific places, these are considered to be less significant than the factors discussed up to this point.
The substance of this chapter is fully summarized, and specially organized, in chapter three, where the process of transforming the principles in the literature into standards is carried out. The analysis of the foregoing is shaped into specific performance standards which clearly define, uniformly and coherently, which characteristics have the most effect and at what degree of articulation the element must be present at.
Literature Addendum
The recently published reports of the Downtown Denver Public Spaces Project (The Denver Partnership, Inc., 1983) are a very significant addition to the literature regarding the pedestrian spaces of downtown Denver. These reports include the Project Overview, the Improvements Handbook, and the Improve ment Proposals. The Handbook outlines the qualities essential to successful public spaces, which includes design features such as seating and landscaping, management ingredients such as maintenance and events programming, and qualities that are referred to as "the magic ingredients." (Ibid. 1983b: p. ii). These 'magic ingredients' are: (1) the accomodation of people-watching (2) flexibility, or variety of uses to attract a variety of people; (3) food and beverages; and (A) special events on stages or in tents (Ibid, ,1983b: p. 8-3). The standards developed in this thesis are similar statements of what qualities public spaces need to insure their success.
The Improvement Proposals report focusses on thirteen public spaces, five of which are examined in detail in this thesis (the DCPA Galleria, Zeckendorf Plaza, Great West Life Plaza, Petro-Lewis Plaza, and Prudential Plaza). The other
eight spaces include the Sixteenth Street Mall as a whole, two sidewalk linkages through parts of the downtown (Curtis and Cleveland Streets), and other spaces outside of the study., area

involved in this thesis. All of the public spaces examined in the Proposals report were recommended for design improvements, special management, or a combination of the two.
The project reports are generally more comprehensive and far more influential than this thesis project in helping plan for the downtown pedestrian environment. The reports do not constitute a plan, however, and their central recommendation is for the development of such a plan, as this thesis also recommends primarily. They do present a resource which is a close substitute for this thesis, and probably a superior substitute, but the approach and scope of the thesis is considerably different. Primarily, the thesis, unlike the Public Spaces Project, contains an evaluation, analysis and recommendations for all the sidewalk spaces, though in a smaller study area. Secondly, the thesis provides an evaluation of both the plazas and the sidewalk network in more complex and detailed terms in some respects. The Project reports provide general criteria and objectives for plaza design, but not standards in the pattern of those established in this thesis. Therefore, the Public Spaces Project and its reports do not eliminate the value or replace the findings and resources of this thesis.

THE STANDARDS Introduction
The author divides all the types of pedestiran spaces mentioned in the literature into two general categories of major plazas and sidewalk spaces, on the basis of their different functions. Plazas, for the purpose of the project, are defined as large open areas (over 10,000 sguare feet, as discussed hereafter), which serve, or potentially may serve, as destinations for large groups of people. Sidewalk spaces are defined as generally linear forms, or as paths along which the full range of urban activity, such as store windows, office lobbies, arcades and even plazas are distributed. Small plazas, entry recesses and sitting ledges along sidewalks are considered as features of the sidewalk environment, and not individually as separate types of pedestrian spaces.
For these two categories of pedestrian spaces, plazas
and sidewalks, two different approaches are provided for measuring their gualities. Twenty characteristics of plazas are
measured, and sixteen of these are defined in detail and esta-
blished as standards for plaza performance. Thirty elements in the sidewalk environment are measured, but the guality of each space is measured by its ranking against four standards that focus on content, concentration and organization of those elements. The standards of plaza guality are more numerous than those testing the guality of sidewalk spaces, because a broader range of complex factors affect the success of plazas. Both types of standards establish classifications of performance, so that a space can be rated as entirely successful, mostly successful, or mostly unsuccessful at meeting that standard.

The Plaza Standards
The success of plazas depend on complex characteristics, many of which defy quantitative measurement, such as their visibility to the public or ability to stimulate people-watching.
These qualities are defined in the following as standards by which to measure the plazas. A four-star grading scale is applied for rating the success of each plaza at most of the standards, whereby four stars would be given to a plaza for successful manifestation of a particular characteristic.
Three stars are generally given for partial success or apparent inaddequacy, two stars for a presence that is so weak that it is nearly inconsequential, and one star for thorough absence of the characteristic or quality defined by the standard. The specific criteria and meaning of each rating will be explained in detail in the discussion of the standards themselves.
The author establishes thirteen of these qualitative standards. Another two, accumulative measures of overall design and the general effect of a plaza's surroundings, are established, using the four-star rating system, but are used for summarizing rather than as actual standards. Five additional characteristics are measured in actual quantities, such as plaza size and amount of seating. Three of these five establish amounts or concentrations of elements as standards for successful plazas, while the other two serve only to obtain basic descriptive data about each plaza. All sixteen standards are adapted and selected from the literature with the professional discretion of the author. The standards are interchangeably referred to as measures, because they show both, whether each plaza fails or succeeds in bearing a particular quality, and to what extent or degree there may have been a failure.
Quantitative Measures
1. SQUARE FEET. This simply reports the area in square
feet of each plaza. Whyte considers the size of plazas to be of no major consequence (1980: p. 26), but the thesis author has found that below about a thousand square

feet, a plaza falls into a category of 'small spaces,' including building setbacks and recesses, which are extensions of the sidewalknnetwork rather than full plazas. Over a hundred thousand sguare feet, a space becomes more like a park, and depending on configuration, may well do severe harm to the cohesiveness of a downtown district, as discussed by Rubinstein (1978: p. 25).
2. LINEAR FEET OF SEATING. This measure identifies the guantity of seating in units suggested by Whyte, who adds that there are about three linear feet to a comfortable seat for one individual (1980: p. 29). This includes, besides conventioanl benches, most ledges, sittable steps, the perimeter of a lawn area, and any other object or space which has been witnessed or could be realistically imagined as a place to sit. Thus some estimations of this quantity are necessary, though the majority of it
may be measured fairly accurately.
Quantitative Standards
3. CONCENTRATION OF SEATING. The efficiency of the plaza
in providing seating is measured by dividing the linear feet of seating into each thousand square feet of plaza area. This measure is derived from Whyte's strongly
emphasized principle that a plaza must have a high concentration of seating to make it a sociable, inviting place (1980: p. 17, p. 27). The formula was developed by the author, for the purpose of comparing the plazas, but after surveying them and lobtaining the figures for their concentration of seating, the figure of twenty linear feet of seating per thousand square feet emerged as the standard for the seating efficiency of an effective, popular plaza.
^. CHOICE AND VARIETY. Though this quality is not always readily or easily measured, it is best expressed by the

number of distinctly different kinds of places to sit in the plaza. Each kind of place would be characterized by sun, shade, quiet water, visibility, seclusion, or other definite qualities unique to a particular part of the plaza. Two identical but separate 1sub-environ ments' would be counted as one, and each one must also have some seating related to it. Jacobs' principle of 'intricacy'(1961: p. 103) and Whyte's stressing that a plaza needs choice (1980: p. 28) are together measured by this test of the complexity of a plaza. The author found that three different types of places in each plaza is an appropriate level and can be considered as a standard. However, while this is an excellent degree of intricacy for a plaza of under twenty-thousand square feet, it may be less satisfactory for a plaza with fifty thousand square feet or more. Thus the measure is somewhat better as a means of describing a plaza than of evaluating it, and the choices a plaza provides should be considered in light of its size, configuration, and ranking at the other standards.
5. EFFICIENCY. Also difficult to measure with a great deal of precision, Whyte's principle of efficiency (1980: p. 101) is applied in one way by measuring the area of the plaza which is seriously lacking in function, and subtracting that from the total plaza area.
The percentage figure which results, indicates in general how much of the plaza is effectively put to use for natural elements such as trees, plantings, lawns, pools, fountains, and anything that controls sun or weather, or social elements like seating, paths through the plaza, and space for vendors, entertainers or sculptures. A ninety percent efficiency was found by
the author to be an appropriate and reasonable standard for a plaza to achieve.

Qualitative Standards
6. VISIBILITY. The first of the qualitative standards,
this measures the visual and easy physical accessibility of the plaza from the sidewalk, a quality which Whyte stressed as important (1980: p. 57). Plazas which
accomplish this fully (A stars) are at street level or only a few steps up or down from the sidewalk, while
a plaza which is above the sidewalk, which appears to require a special effort to investigate it, and has nothing to make itself known, is a complete failure at this test (1 star). A plaza which is visible but is walled off or sunken in a way that prevents a casual strolling through, is rated as a limited success (3 stars). A limited failure at this test would be when a plaza has a substantial part which is difficult to see or enter from the more visible parts of the plaza (2 stars). This quality is vital to how plazas and sidewalks extend into and through each other, sharing amenities and funtions. 7
7. SAFETY. From Jacobs, three different types or sources of surveillance which discourage crime can be identified, largely adapted from her principles of sidewalk safety. (1961: pp. 35-6). A plaza can be considered as safe
(A stars) if all three of these sources are active, mostly safe (3 stars) if two of the three are active, and mostly unsafe (2 stars) if only one source is in effect. An unsafe plaza (1 star) is bordered by blank walls that disallow observation from neighboring uses, and is invisible from the street because of its elevation away from the street or use of walls. Also, it has design features that fully block the view of one major part of the plaza from another part, particularly from the main plaza area or its main pathways through or across it. The three sources of crime monitoring,

then, are adjacent uses, the street and the plaza itself (Ibid.). Of course, there are other influences of time of day, location, social character, and plaza use which may make a plaza more or less safe from crime.
SUN. Whyte and Oacobs both state that sunlight is a key ingredient for plaza success, but they do not specify a real standard of what amount of sun is necessary. Whyte says only that there should be sunlight allowed by the surrounding buildings, and that design features such as trees, sun traps and canopies are necessary to make the most of it and provide choice.
(1980: pp. 42-5). Jacobs primarily warns against long building shadows (1961: p. 105). A standard for sun could focus on how the design of the plaza utilizes the sun, but the primary problem is how much sunlight in terms of time and area a plaza gets, so this standard is heavily improvised. If a plaza has a winter sun striking a substantial part of it for more than three hours a day, it is considered to have the most sun one could realisitically expect in a downtown the form and size of Denver's (4 stars). If sunlight in the winter crosses only a small part of the plaza for that amount of time, or most of the plaza for under two hours, its sun is considered good but inadequate (3 stars). A plaza with very limited sun ( 2 stars) is defined by the significant presence of sun only in the summer, and by very little winter sun (under an hour or shining onionly a very small part). A plaza that seriously lacks the sun would receive sunlight only in the summer, for under two hours (1 star).
ENCLOSURE. This standard applies the analytical method suggested by Rubenstein, which defines buildings as verti-

cal planes of enclosure (1978: p. 33), and Jacobs' more general understanding of how buildings create definite shapes and volumes for plazas (1961: p. l'06). A well-enclosed plaza would have highly discernable planes of enclosure at each side of the plaza (4 stars). If the plaza is surrounded by buildings on only three sides, or by buildings that are strongly set off from each other, the degree of enclosure is considered moderate (3 stars). The plaza would be rated as having poor enclosure if there is no building at all on one side of it, or if the building facades around it produce only two definite spatial 'walls' (2 stars). An unenclosed plaza would be one with no more than one recognizable plane of enclosure (1 star). Some plazas may deserve 'extra credit' if their design contributes to the sense of enclosure, however. 10
10. CENTERING. How the plaza provides for people-watching, performance and exposition of special events, depends on how it manifests Jacobs' concept of a focal point or climax (1961: p. 104), and Whyte's idea of an amphitheatre effect, of people looking at people looking at the show. (1980: p. 59). Such a place within the plaza assures the people's stage and the opportunity for self-representation suggested by Uhlig (1979: p. 6), and allows for the new social habits envisioned by Brambilla and Longo (1977: p. 41). Two generous sitting ledges across from each other, with a central walkway or item of special interest, such as a sculpture or fountain between them, is a full success (4 stars). When the majority of the seating faces only a large open plaza area or a sidewalk, and is broken up in isolated benches, and no center is apparent, then the plaza has failed the test (1 star). If a center is clearly there, but the seating is broken up and limited, it is only a part

success (3 stars). A plaza with seating areas poorly oriented to each other fails mostly at this effect (2 stars).
11. INTEREST. This further measures how Jacobs' principle of 'intricacy' is achieved by a plaza Is design, but more in terms of how it attracts people for specific reasons (1961: p. 103). To a greater extent, though, it is drawn from Whyte's argument for special activities or dramatic elements, such as ice skating and musical performances in the case of the former, and sculptures and big water features in the latter (1980: pp. 94-8. pp. 47-8). Complete success (4 stars) and complete failure (1 star) are defined simply by the presence or absence, respectively, of anything worth looking at, playing on, talking about or bringing out-of-town guests to see. If the element is not visible from throughout the plaza, it is considered a limited success (3 stars), and if it is so small in relation to the size of the plaza to be easily ignored, then it is a limited fail-* ure (2 stars).
12. USE GENERATORS. This is taken from Jacobs' principle for both sidewalks and plazas, to measure the degree of diversity among neighboring land uses, which brings people near to and often into the plaza for different reasons and at different times (1961: pp. 96-8). A full success requires that more than one kind of use, among categories of offices, stores, restauraunts, hotels, housing, and other clearly divergent land uses,
be directly accessible through the plaza (4 stars). A part success is when there is no diversity of land uses in the plaza block itself, but there are uses different
from the plaza block's uses in immediately adjacent block faces, and in at least two distinctly different

directions away from the plaza (3 stars). If that diversity is in only one direction, or constitutes only minor, limited amounts of diversity, it is judged as a part failure (2 stars). When the plaza is surrounded entirely by one land use, such as offices, the plaza is without use generators to the extent dacobs would find necessary (1 star).
13. USE. Whyte's suggestion that plaza users attract
still more users is the primary isssue here (1980: p. 100), though the degree of use is itself the greatest determinant of how well all the characteristics have performed and contributed to the use of the plaza. So, use means both that the plaza will be more successful, and that it i_s successful. However, no detailed survey of use was conducted, and the rating of each plaza in this respect is based simply on the author's experience, knowledge, and observation over time of the plazas. Downtown Denver's plazas are put to use almost exclusively during the lunch hour in warm weather, by office workers having a meal from home, a vendor or fast-food restaurant, and these are the conditions and time when the plazas are considered for this test. A full success is when the plaza has been used as fully as is conceivable, given the amount of seating (A stars). A part success (3 stars) is defined by a plaza which has a level of use that is notably short of its potential, a part failure (2 stars) by a plaza which falls far below its capacity, and a total failure (1 star) by a consistent absence of users.
1A. FOOD. Ihis is a simple yes (4 stars) or no (1 star) test of whether or not food vendors are regularly present, taken from Whyte's suggestion of this as an essential ingredient of a lively plaza (1980: p. 50).

13. TREES. Another element considered by Whyte as vital to a plaza's design (1980: p. 46), how the plaza is dominated by trees is tested by this standard. A full success is exemplified by a general covering of the plaza, but still allowing areas of sunshine in which to sit (4 stars). If there is a gap between the trees which is clearly too great, given the size of the plaza, it is considered as a gualified success (3 stars). If the trees are nearly insignificant, it is mostly a failure (2 stars), and if they are entirely absent, it is an entire failure (1 star).
16. PLANTINGS. This is an additionaltest of the concentration of natural elements, which is generally suggested
by Jacobs as a pleasant contrast to the concretendf the city (1961: p. 103). Success is defined by the substantial presence of planter boxes and beds for flowers, ground cover, and shrubs (A- stars). If these plantings are poorly tended and sickly looking, or are relatively few in number, or are only provided through small, freestanding planters, it is considered a part success (3 stars). If there are only free-standing planters, and these are not in good condition, or are limited in relation to the plaza's size, it has mostly failed this test (2 stars). A complete failure is marked by the absence of any effort at plantings (1 star).
17. LAWN. This measures, like the food test, simply the presence (A stars) or absence (1 star) of sittable, well-tended lawn areas, which Whyte recognizes as an appropriate natural element to be included in plazas (1980:
p. 4-6). However, if the lawn is in poor condition, or is a relatively miniscule part of the plaza, it is rated as only a limited success (3 stars).

18. WATER. This element is considered by Whyte to be a consistently delightful ingredient of successful plazas (1980 p. ^7). Though there are great differences in the scale and quality of plaza water elements, how frequently it is in operation, and its relation to the whole plaza, will affect its success. A water feature which operates for at least four months of the year is a full success (4 stars), but if it runs less than that, or is a nearly insignificant plaza amenity, it is a more limited success (3 stars). Those water features that operate very rarely, or not at all, are near failures. A plaza rates as a complete failure if it has no operable water feature at all (1 star ) .
Accumulative Measures
19. OVERALL DESIGN. This is an accumulative measure of the above standards of seating concentration, choice and variety, efficiency, visibility, centering, interest, trees, plantings, lawn, water, and the characteristics of enclosure and safety contributed by the plaza's own design.
An element of the author's 'gut feel' for a plaza is also entered into this measure, which focusses on the plaza's design elements. The best designed plazas rate as successes when they have remarkable effectiveness at meeting the standards (4- stars), and those which have a mix of success and failure at the standards are rated as part sue cesses (3 stars). When the plaza is dominated by ineffectiveness in achieving the standards, it mostly a failure (2 stars), and if it fails at nearly all of them, it is an absolute failure (1 star).
20. SURROUNDINGS. This additional accumulative measure is meant to show the way the surrounding buildings contribute to the success of the plaza by their density, diversity, presence as planes of enclosure, sources of safety monitoring, and non-interference with sunlight.

Food vendors also contribute to a plaza's rating in this measure, which is directed at factors other than design guality. The plazas with the most supportive surroundings are those with particularly strong expression of these qualities (4 stars), and a plaza which has only moderate, or mixed degrees of success at them rates as one with somewhat weak surroundings (3 stars). Those plazas which derive little benefit from the nearby buildings, uses and so forth, rank below average in this measure (2 stars), and as having very serious problems if there is nothing in the area to generate use or create desirability of the plaza (1 star).
The Sidewalk Standard^
While plazas serve a broad range of functions and need several qualities to be insured of their use and value to the public, sidewalks serve the simpler role of providing links between the plazas and among all the various land uses and businesses of a downtown district. These linkages, however, can make walking in the downtown a pleasure, depending on their image, activity and interest. The author's approach to evaluating these linkages is to divide the entire study area into sections of between 100 and 700 feet in length, and carry out a very simple description and evaluation of each of these sections. Each section's length and ending points are established on the basis of a particularly strong environmental aspect, such as the character of the building or buildings facing the sidewalk, a line of trees, or a surface parking lot. The sidewalk spaces are divided generally where the type of environment changes dramatically, which may be simply at a block corner, or in the middle of a block, where, for example, an expanse of window displays meets with an expanse of blank walls, or a parking lot or even a plaza. Some divisions are made more for reasons of establishing a space of reasonable length, although the type of environment may

clearly cross the dividing line. Most of the spaces are divided by streets, but in two types of spaces both sides of a street are evaluated as part of a single space. Most commonly this is done along the Sixteenth Street Mall, where cod-, pedestrians may cross from side to side with only the interference of periodic shuttle buses, and the amenities are distributed evenly to give each side a common image. The other type of environment where the sidewalk space crosses a street, is where the presence of an overhead pedestrian bridge creates an intimate, unified space between buildings and encourages, in spite of jaywalking laws, pedestrians crossing from one side of the street to the other.
The division of the district on this basis establishes 160 sidewalk spaces, and because of this large number, individual analysis of each space is inappropriate for the scope of this project. A description of each space is provided through the measurement of thirty elements, such as trees, street furniture and window displays, which occur at points along the sidewalk or in closely parallel lines, making them easy to quantify. Some elements are measured for descriptive purposes only and do not bear on the evaluation of the spaces, which is achieved by using four standards. The standards provide for each space to be ranked between one (I, high) and five (V, low) for its degree of quality or interest to the pedestrian. The description of these four standards defines in detail the elements and specific combinations of elements which serve as the criteria used in assigning rank to each sidewalk space. Thus, the measurement of the thirty elements provides a description of each space in the simplest possible terms, and the four standards serve to identify the relative quality of the space on the basis of that description.
The thirty elements are listed first, with accompanying statements to clarify what is and is not counted, and in what units certain features are measured. Also, the basis of each element in the literature, or on other grounds, is stated.
The thirty-first 'element' to be measured in each sidewalk

space is its length, which is an essential part of the formulas used in some of the standards to define the ranking of a space. The standards are then described in detail, thereby creating a list of thirty-five items which are measured in each of the 160 sidewalk spaces. The complete results of the survey are presented in matrix form on sixteen pages in appendix 2. The analysis of the spaces in chapter five will be focussed around the rankings of the spaces against the standards, the patterns that groups of the spaces establish in the downtown, and on possible means of solving the problems that are revealed by the analysis .
Sidewalk Elements
1. Trees: the number of trees in the section and in immediately adjacent plazas, regardless of their age, breadth or variety, but excluding dead trees. This element is suggested by Oacobs (1961: p. 390) and Rubinstein (1978: p. 26) as a unifying element for the street, and generally by the Downtown Denver, Inc. Design and Environment Committee (1977: sec. 1.1).
2. Healthy Planters: the number of free-standing planters, or each five feet of surface plantings paralleling the sidewalk, also without regard to size or variety of plant materials, but including only well-tended, healthy plantings. Brambilla andLongo suggest these amenities for the sidewalk environment (1977: p. 35, p. 115), and they are common features in downtown Denver as 'streetscape' improvements .
3. Empty Planters: including planters with dead or dying plant materials, dirt only, and those which are actually empty.
A common, but undesirable feature of Denver sidewalks, these fixtures nonetheless provide an extra trash receptacle, or even a sitting ledge, on occasion.

(wood or metal, for example), which typically extend the full length of a business or building frontage along the sidewalk.
16. Small Recess; each covered building recess, entryway or other space, which is adjacent to and easily accessible from the sidewalk. These spaces should be in a roughly square, rectangular or circular configuration, and are distinguished from the following element of large recesses by their size. Initial surveillance of the spaces by the author indicated that some such spaces serve only to shelter a few people while they wait for a bus or a friend out of the weather or pedestrian traffic. These spaces, which have little or no capacity for seating, were figured as having under two-hundred and fifty square feet of area. These spaces were recognized by Whyte as having great potential as small delights of the pedestrian environment. (1980: p. 99).
17. Large Recess: each covered area of the same general description as immediately above, except that these are from two-hundred and fifty to a thousand square feet in area, and have real capacity for seating, planters or other features. Such spaces have greater potential than the smaller spaces of contributing to the downtown in the terms suggested by Whyte (Ibid.). A covered space of greater than a thousand square feet would be listed as a special amenity.
If it occupies an entire side of a building, facing the sidewalk, it is considered as an arcade, described below.
18. Arcade: each twenty-five foot length of arcade which runs the full length of a building side along the sidewalk, and is at least ten feet wide. It is distinguished from a canopy by its structural integration within, and often under the floor area, of the building. Arcades

are mentioned briefly as a desirable feature in the Downtown Denver Development Plan (1978: Development Plan section) in the Skyline Urban Renewal Plan (1967: p. C-4), and in the Denver Planning Office's Design Guidelines for the Sixteenth Street Mall (1980: p. 15). However, the author considers arcades as somewhat greater in importance as potentially unifying elements of a sidewalk space.
19. Plazas: each twenty-five foot length of uncovered plaza border directly adjacent to and accessible from the sidewalk, including plazas too small to be considered in the in-depth plaza analysis chapter. Besides being vital urban amenities in the view of the Downtown Denver Development Plan (1978: Conclusion section), plazas are a land use which affect tremendously the quality of the pedestrian experience from the sidewalk, providing the larger areas withing the pedestrian network that Uhlig claims make walking a highly social event (1979: p. 6). They also give unity to a large section of sidewalk.
20. Vendors: each individual vendor, disregarding merchandise, quality of appearance and length of time on site per day. These valuable pedestrian services are suggested by Whyte for plazas (1980: p. 50), but are clearly appropriate for distribution throughout the downtown.
21. Historic Facades: the number of twenty-five foot lengths of building facade along the sidewalk which has prominent and wel1-maintained historic detail, dating from before 1930. That year is the watershed year used by the Sixteenth Street Mall Design Guidelines, which states that post-1930 buildings have distinctly different, simpler
and more modern appearances, lacking the richness of detail in pre-1930 buildings (1980: p. 12, p. 27). These features of the urban environment are considered as major

elements of the sidewalk environment by Brambilla and Longo (1977: pi 3). When these facades are made clearly visible and attractive, the beauty and order of cities as seen by Jacobs is made evident, and the street's appearance can be greatly unified (1961: p. 373).
Window Displays: the number of twenty-five foot lengths of windows which provide direct views from the street of generally continuous arrangements of merchandise, information or other items of interest. Separate display cases and windows are totalled, and a simple double-door entry would be included if bordered by window displays.
This measure is mostly derived from the recommendations for continuous retail inctbe Sixteenth Street Mall Design Guidelines (1980: p. 10), and from the Downtown Denver Development Plan, which stresses the need for sidewalk-directed shop windows to create interest and activity along Denver's sidewalks (1978: Development Plan section).
A continuous pattern of window displays, Rubinstein suggests, can also be a means of unifying the image of a street (1978: p. 26).
Populated Windows: the number of twenty-five foot lengths of building frontage along the sidewalk which affords clear views of groups of people lunching, dining, or conducting business. This measure includes simple double-door entries bordered by such windows. It measures activity facing the sidewalk which acts as a source of crime safety monitoring, as Jacobs would suggest (1961: p. 36), but also adds interest and something to observe from the sidewalk where retailing does not border it.
Blank Windows: the number of continuous, twenty-five foot lengths of building frontage dominated by windows, through which no activity or interest is visible, or which are

highly reflective or functionally opaque. Large sets of doors with similar characteristics are included.
This element and the following element, blank walls, are considered detrimental to the Sixteenth Street Mall by the Denver Planning Office in their Design Guidelines for the Mall (1980: p. 16), and such building characteristics are equally harmful to the entire downtown's system of pedestrian spaces.
25. Blank Walls: the number of twenty-five foot lengths of continuous building wall at street level along the sidewalk which lacks windows, entries or other similar functions.
It includes walls with only a very few windows, and walls with special treatments of brick, marble or special designs, though if the treatment is truly remarkable, it will be noted as a special amenity. Besides being condemned in the Sixteenth Street Mall Design Guidelines (Ibid.), the Downtown Denver Development Plan recommends street level commercial space in parking garages specifically to avoid the blank walls that are typical of conventional parking garages (1978: Development Plan section).
26. Parking Garages: the number of twenty-five foot lengths of sidewalk frontage of structural parking garages, or covered bank drive-up windows, where the auto area is generally visible from the sidewalk. This type of sidewalk environment character is more specifically what the Downtown Denver Development Plan was partly aimed against, as explained above (Ibid.).
27. Surface Parking: the number of twenty-five foot lengths of surface parking border paralleling the sidewalk, including sunken but uncovered parking lots. This element is not dealt with particularly by the literature, but it represents a very low level of use of urban land, which

Jacobs strongly discourages (1961: p. 216).
28. Use Diversity: the number of distinct land uses within the building or buildings facing the full length of the sidewalk section, among categories of: office uses, including governmental offices, bank lobbies and professional offices; retail, including personal services such as barbers; restaurants; hotels, residential uses, including long-term occupancy hotels; cultural uses, such as theatres and convention halls; educational institutions; athletic clubs; plazas; and parking. This measure is meant to identify how Jacobs' principle of use diversity (1961:
p. 152) is manifested in each sidewalk space.
29. Building Diversity: the number of individual buildings facing the full length of the sidewalk section, which is an important indication of the potential for intricate diversity, as interpreted by Jacobs (Ibid.: p. 188).
30. Frontage Diversity: the number of individual institutions or enterprises which have entries directly onto the sidewalk, thereby excluding all office building lobbies. This shows the sidewalk section's intricacy from another angle, also suggested by Jacobs (Ibid.: p. 390), of how the storefronts and other commercial activity occupies small or large segments of the length of a block.
31. Sidewalk Length: the linear feet of the sidewalk section studied, rounded off tb the nearest ten feet.
Sidewalk Standards
32. SIDEWALK CHARACTER. Several of the above elements have been diocussed as having the capability of unifying the space, and it may be said that some of these achieve that effect better than others. Trees do the very most to

give a space a positive image and identity, and other elements that improve the image of a space have a greater contribution to make if they are complemented by a series of trees. The first class (I) of spaces have trees generally from one end to the other, and have at least one of the following elements running throughout it as well: special amenities (if judged 'special' enough); awnings; canopies; arcades; plazas; historic facades; or window displays. The second class (II) of spaces are those that are unified by trees only, or have in addition, special paving, low level lighting or a special amenity of a very ordinary, unremarkable kind throughout the space. Spaces in the third class (III) are marked by the absence of trees throughout the space, but are unified by the presence of at least one of these elements: high quality special amenities; awnings, canopies; arcades; plazas; historic facade; or window displays. The spaces in the fourth class (IV) are those unified only by lower quality special amenities, special paving or low level lighting. Lastly, those spaces with no elements of unity at all are marked among the fifth class (V).
33. SMALL SPACES. This measure seeks to identify the number and location of types of pedestrian spaces which allow people to sit and relax for any reason, or which have such potential. It also identifies spaces which may make the downtown a little more interesting. It directs attention to spaces that may border only a limited part of a sidewalk section. The first class (I) includes sections with open spaces that are most like regular plazas, of at least a thousand square feet and containing a good concentration of seating and other amenities. The spaces along the Sixteenth Street Mall are ranked in this class, because each block of the Mall is in effect a small plaza, though with the most minimal seating. The second class

(II) of spaces are those with building recesses or setbacks of under a thousand square feet of area, open or covered, and which have some seating, or at least some item of special interest. Third class (III) sidewalk sections are those with with spaces of approximately a thousand square feet or greater, but which have inadequate seating, or lack the amenities to make them particularly attractive. The sections in the fourth class (IV) are those with spaces of under a thousand square feet, with clearly inadequate seating or unappealing amenities.
Fifth class (V) sections are those with no building recesses, arcades or setbacks at all, though some of these may provide seating of some kind.
3A. LAND USE CHARACTER. This measure focusses on the
interest the sidewalk segment has to the pedestrian through its concentration of window displays, blank windows or other building characteristics. The first and last classes are highly specific, identifying in very straight-forward terms the kinds of spaces that have the most interest and those that have the least. The middle three classes, on the other hand, are more general and broad, covering the wide range of various combinations of building and land use character. If a space's land use character does not fit the actual descriptions of these classes, it is ranked by the surveyor according to its general nature as above average, below average, or neutral, and by its qualitative similarity to the middle three classes. Concentration of a particular building or land use character is determined by dividing the number of twenty-five foot lengths of a particular category that a segment may have, into each hundred feet of sidewalk length.
Those spaces that rank in the first class (1) have at least 75 percent, or an average of 3 in each 100 feet,

of window displays or populated windows, and the remainder contains no blank walls, parking garages or surface parking. Second class spaces include those with between 25 and 75 percent active windows, or an average of between 1 and 3 in each 100 feet, also without any blank walls, parking garages or surface parking in the remainder, which may consist largely of blank windows. Also in this class are spaces with at least 50 percent active windows when the remainder contains any amount of blank walls, parking garages or surface parking. Lastly in this class are those spaces which have at least 75 percent good, street level historic facades, though the windows may be blank. Other building and land use characteristics of a space which do not fit the specific descriptions of the classes in this standard, may be considered as justification for placing the space in this class, if the effect is generally more positive than negative.
The third class (III) spaces are those with under 25 percent active windows, at least 50 percent blank windows, and no more than 25 percent parking garages, surface parking or blank walls. This class would include spaces which are very neutral, having a generally balanced mixture of positive and negative land use characteristics, or characteristics which are not particularly good or bad. Large plazas and heavily landscaped building setbacks which separate buildings from the sidewalk, are considered as egually passive as blank windows, in comparison to the positive interest of window displays and the negative effect of a large parking lot. Thus, where plazas dominate the length of a segment, the segment is rated as neutral (III) in land use character.
Those spaces ranked in the fourth class (IV) contain at least 75 percent blank walls or parking garages. The content of the remainder is considered to be inconsequen-

tial, whether it is made up of window displays or surface parking. Spaces with other land use characteristics which are equally without pedestrian interest, excluding those that fit into the fifth class, would rank in this fourth class as well. Fifth class spaces are those that have surface parking bordering over 50 percent of their length, and the remainder consists of blank walls or parking garages.
35. DIVERSITY. This standard establishes a means of ranking the spaces according to the concentration of differing uses, buildings and business frontages. By dividing the total number of these elements of diversity (the total of measures 28, 29 and 30) into each hundred feet of sidewalk section length, an indication of the space's concentration of diversity is obtained. For all the Denver sidewalk spaces, the resulting figures range from below \ an element (a land use, building or business frontage) to over 3 elements per hundred feet of sidewalk length.
The sections ranked in the first class (I) are those with at least 3 elements per hundred feet. The second class (II) spaces are those with between 2 and 3 elements per hundred feet. Third class (III) spaces have from If to 2 elements, and fourth class (IV) spaces, from f to If elements per hundred feet. Lastly, those with below f an element per hundred feet are ranked in the fifth class (V).

This thesis recognizes fifteen major plazas within its project boundaries, which are shown in figure 2. There are many more plaza-like spaces in the downtown, within this study area, which could be examined as these fifteen are in this chapter. However, they are all much smaller spaces which are not used as these fifteen are, but more as extensions of the sidewalk environment, and are therefore dealt with in the next chapter, as elements of sidewalk spaces.
Each plaza is presented individually in this chapter with one or more photographs, a table showing the descriptive data and ratings against the standards, a written description, and further paragraphs evaluating and making recommendations for the plaza. Analyses, evaluations and recommendations are made for the plazas as a group following the discussions of the individual plazas, using some graphic figures and tables of data. The first three plazas, which together constitute Skyline Park, are introduced by a general discussion and evaluation.
Skyline Park
A public development, unlike most of Denver's plazas, this linear park runs the full length of the 1500, 1600 and 1700 blocks of Arapahoe Street, a total of 1200 feet in length, excluding the Sixteenth Street Mall and the right-of-way of Seventeenth Street. It is 100 feet wide, excluding a sidewalk which lies between the park and adjacent buildings, making each block individually among the largest of the downtown plazas

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at 40,000 square feet each. The amount of seating is quite high, and because of the complexity of the seating's arrangement, each block is simply estimated to have 1000 linear feet of seating as a minimum.
Though the park is largely concealed from the street by the berm between the central, slightly sunken pathway and the street (see figures 4, 9, and 10, on following pages), it is very visible and accessible from the sidewalk that divides the Park from the properties along it. This unique configuration establishes two main pathways through the Park, one along the adjoining land uses, and another, distinctly separate from the street and the buildings. But because of the strong separation of the street from the Park, the safety of the Park is somewhat flawed.
All blocks of the park have generally good sun, and low levels of enclosure. Centering and interest are achieved very effectively by the waterfall sculptures in each of the blocks, designed by the nationally recognized landscape architect Lawrence Halprin, who also designed the Park itself.
Use of each block varies greatly according to the adjacent land uses, but the density of the surroundings has been generally quite low compared with other parts of the downtown. All the blocks have a great amount of trees (about 100 each), plantings and lawn areas. The water elements in each block are capable of running year-round, but they typically operate during no more than six months of the year, and the waterfall structure in the 1600 block is very rarely operated at all. However, even when dry, these sculptures are inviting play structures. Still, when running, they make a wonderful amount of noise, the way a Colorado mountain stream would, and are thus particularly appropriate to the region.
The park has truly remarkable design features in the variety of its seating areas, its high efficiency, and strong

centers. Its character as a park is heightened by the suitability of the sculptures for childrens play, the quality of the park as a quiet retreat and refuge from the city, the picnic-scale lawns and concentration of trees and plantings.
A phenomenon of the Park, though not a serious problem, results from the design and form of the Bark, whereby many park users will sit on the berm dividing the street and the park, and face the street. This is not from a shortage of seating in the .inner portions of the Park, but from an apparent decision that what goes on in the street may be more interesting. People also walk along the street, despite the absence of any sidewalk at all, lending confirmation to the principle that plazas and pathways ought to be open to and integrated with the street, in spite of its noise and seemingly undesire-able activity.
Figure 3
Arcade in 1500 Skyline (Park Central)

ure k
(Park Central)

1500 Skyline (Park Central) Figure 5
Descriptive Data and Ratings,
Square Feet: Linear Feet 44,000
of Seating: Concentration est. 1200
of Seating: Choice and 27.3
Variety: 6
Efficiency: 96 %
Use Generators:
Food :
Lawn :
Overall Design:
This block has greater seating capacity as a result of a wide area of steps beneath the office building, behind the arcade on the right of figure 4, towards the bottom of the
photograph. This area, shown in detail in figure 6, func-
tions as a real part of the park and also extends this particular block's area by 4,000 square feet, and its amount of seating by 200 linear feet. The arcade and the function of the waterfall sculpture as a play structure is shown in figure 3. The choices of places to sit in this block are between: (1) on the steps in the arcade; (2) around either of the two larger, open areas at the two ends of the block; (3) on the lawn or ledges facing the narrower, central pathway; (4) on the lawn facing the street; (5) in one of the two room-like enclosures in the lower right of figure 4; and (6) around, on, or in the waterfall structure in the upper right of figure 4. The efficiency of this block of the Park is
extremely high, but the open area at the bottom of figure 4

is excessively large, though it is used occasionally as a performing area.
Because of a low building and surface parking to the left off of figure A-, across the street to the southeast, the park receives a great deal of sun, but a winter shadow from an apartment tower directly to the south,, does e3.imi.nate the sun at mid-day for three months of the year over most of the plaza. Enclosure is weakened by the absence of any noticeable building to the southeast, b u t t h e buildings on the remaining three sides, and the park's form, particularly the berm, lined with trees, produce a moderate sense of enclosure.
Figure 6
Area of Steps, 1500 Skyline
Though a restaurant has just opened in the office building on the right of figure A-, its entrance is on the opposite side from the park, and does not bring people through the park, any more than the hotel, residential and retail uses in neighboring blocks do. The diversity of uses 1n the vicinity of the plaza is above average for the downtown, but their concentration and density are not high enough to generate the amount of use that this plaza should ideally have. Despite the emptiness of the plaza shown in figure ^, it is a very

well-used park during the lunch hour, and is the most used of the three blocks of Skyline Park. It is the only block where a vendor has been active, at the extreme upper left-hand corner of figure 4.
This is clearly one of the best plazas in the downtown because of its fine intricacy and great amount of amenities.
The small room-like spaces, when canopied by the trees in the summer, are exceptionally pleasant, and are not repeated anywhere in the downtown, unfortunately not even in the other blocks of Skyline Park. The waterfall sculpture in this block is designed to evoke large boulders common among Colorado mountain streams. The arcade of the office building, which extends the full length of the block, is a unique amenity, bringing the building right up to the park edge and making the two interact with each other quite effectively. The use of the steps behind the arcade indicates its desirability, but seating in the arcade is too limited by its restriction to the steps, which line only 100 feet of the 4-00 foot length of the arcade.
The design qualities of the surroundings, however, contrast extremely, between the massive modern block glass and steel of the building in figure ^, and the much \smaller, historic facades at the two ends of the park, off the top and bottom of figure k. Further, negative contrast is produced by the
absence of any plane of enclosure on the southeast side of the park. The domination of the park by the massive block-like building would offend 3ane Jacobs, it is certain, but the whole effect is softened by the trees, lawn, water and high usage of the park. Although it is given the highest rating for usage, there is much more capacity for use, and the low density of the surroundings are clearly responsible for the somewhat inadequate use. The mixture of uses in the area, including a university campus and performing arts center a block away, and

direct bordering of the park with the Sixteenth Street Mall, should stimulate tremendous park use, but the lack of retailing, restaurants and services immediately adjacent to this plaza, does not give the users of those facilities any reason to visit this block and its fine plaza.
There is no need for any significant changes in the design of this block, or any block, of Skyline Park. But given the observed popularity of the steps along the arcade, some simple benches along the sides of the arcade would be appropriate, to create a very pleasant new type of sitting area in this plaza. Though vendors occasionally operate at the borders of this plaza, they should be encouraged within the park itself, perhaps in either of the two open areas at each end of the block.
Most of all, however, the uses within the office building facing the plaza, on the ground floor at least, should be changed to include some retailing, restaurants and personal services. Outside of the block, development of the surface parking lots to the southeast and southwest should be encouraged, with retailing, restaurants and housing, to generate more people in this area of the downtown. A new building on the southeast could improve the degree of enclosure, but should be designed carefully to not interfere with the plaza's existing share of sunlight. A new development under construction, on two blocks behind and to the left of the photographer of figure A, discussed hereafter as it relates to the 1600 block of Skyline Park, will contain a very large amount of retailing, and several restaurants, which should affect this plaza very positively in terms of generating users. However, this plaza would benefit the most by adding some of its own stores and cafes.

Figure 7
Overhead Photograph, 1600 Skyline (Tabor Center)

1600 Skyline (Tabor Center)
Figure 8
Descriptive Data and Ratings,
Square Feet: Linear Feet 40,000
of Seating Concentration est. 1000
of Seating: Choice and 25
Variety: 5
Efficiency: 95 %
Centering :
Use Generators:
Overall Design:
The amount and concentration of seating in this block of Skyline Park is standard for the Park, but is in a somewhat simpler form than that of the 1500 block. The seating is mostly arranged around the two open plaza areas at the top and bottom of figure 7. The choice of sitting areas are among: (1) on the steps around the open space at the bottom of figure 7, also shown by figure 9, from another angle; (2) on the steps around the waterfall sculpture; (3) around, on, or in the sculpture; (4) on the lawn facing the street; and (5) on the lawn at the center of the block, between the retaining wall and the storage area at the right of figure 7. Though the open plaza area at the bottom of figure 7 and in figure 9 was apparently intended as a performing area, it is a waste of space without such activities and is the one inefficient area in this block of Skyline Park. This block has a lower level of safety due to the lack of a completed development along its northwestern edge, as shown on the left side of figure 7.

.6 5
F i g u r e 9 1600 Skyline Amphitheatre Area
The park has a great amount of sunlight across it from midmorning to mid-afternoon in the winter, when the photograph in figure 7 was taken. The park has no buildings around it with strong planes of enclosure, though the new building adjacent to the park will add such an element. At the present, the raised berm and sunken plaza floors create a limited sense of enclosure. The waterfall sculpture, though it is dry year-round, is still a fine sitting and playing structure and works well as a center. The low level, of use of the park is related most of all to the undeveloped land it shares the block with, but is also a lesser result of the low density of the surraundings. Food vendors have little or no reason to be here because of the low use.
Like all the blocks of Skyline Park, the existing design is superb, but this one seems especially well-suited for programmed activities, vendors and outdoor restaurant tables.
The area at the bottom of figure 7, and in figure 9, has excel-

lent potential as an amphitheatre, and pillars such as the one at the right in figure 9, contain light fixtures for such activities at nighttime. The area around the six grouped trees just left of figure 7's center, because it has no seating around it, seems to be meant for a trio of food vendors or a bunch of tables and chairs. The only notable design flaw is the high retaining wall dividing the lawn and the 'amphitheatre' area, which makes the lawn inaccessible and almost invisible. The high retaining walls along the pathway connecting the two main areas, which are useless as sitting ledges could be a flaw, but it serves to 'squeeze' people into one or the other of the main areas, which may be desirable in social terms. The area at the top of figure 7, is much different from the other main area, because of the way the steps are 'wrapped' around the waterfall sculpture, which is in turn an informal stage for the public to 'perform' on. This sculpture bears little resemblance to natural waterfalls in the Denver region, but has an interesting similarity to the Denver skyline.
Because of the lack of an active commercial use of the adjacent property, there has not been, since the Park was built over ten years ago, anything to bring people into this block other than idle curiosity. Also, the absence of uses along it, other than surface parking, created an image of being unsafe, because of the lack of surveillance which commercial activity, and the people it would generate, would provide.
Only the commercial and office uses in the neighboring blocks bring users to this park, but most people will tend to go to the other blocks of Skyline Park, or to other plazas in the vicinity (see figure 2). Furthermore, the density and diversity of uses in this area is not significant enough to generate a large number of users. However, the surrounding build-
ings, to the south and southeast are situated to give this plaza a great deal of sun. The major Denver landmark, the Daniels and Fisher Tower, from which the photgraph of figure 7 was taken, and which forms the shadow over the plaza in the

photograph, is an excellent aesthetic feature of this plaza.
The development of the neighboring land is clearly the most critical to extending the use of this plaza, and as is equally clear from figure 7, that development is approaching, though its completion is over a year away. The project will include a large shopping galleria, a hotel and a number of restaurants, besides two office towers, across two blocks, and will establish retailing along the Park. The park's problems of safety and use generation should be resolved quite effectively by the project, along with improvements, very likely, in the presence of vendors and the operation of the water sculpture. A strong plane of enclosure on the left side of figure 7 will be established, but the great openness created by the building on the opposite side of the park, across the street, and the continuity of the Park to the next block along Arapahoe Street, will prevent the degree of enclosure of this plaza from becoming completely effective.
The area around the six grouped trees just left of the center of figure 7, would be very suitable for movable chairs and tables, possibly in association with a restaurant within the new development. The significance of the project can only be fully determined after it is complete and has been functioning for several months or a year. In the meantime, the water should be running in the fountain, and if at all possible, musical or theatrical events programmed in the 'amphitheatre' area, which may be the most suitable location for such activities in the entire Skyline Park, perhaps especially because of the powerful landmark of the D & F Tower.

higure 1U
Overhead Photograph, 1700 Skyline (Denver

1700 Skyline (Denver National Bank) Figure 11
Descriptive Data and Ratings, 1700 Skyline
Square Feet: 40,000 Interest:
Linear Feet of Seating: est. 1000 Use Generators:
Concentration Use:
of Seating: 25 Food:
Choice and
Variety: 5 Trees:
Efficiency: 100 % Plantings:
Visibility: Lawn:
Safety: Water:
Enclosure: Overall Design:
Centering: Surroundings:
The variety of places to sit in this block include: (1) on the lawn or ledges facing the central pathway; (2) on the lawn facing the street; (3) on the benches facing the office tower across the 'sidewalk' in the left half of figure 10*; (4) on the
steps arourtd the waterfall at the extreme right of figure 10, shown in figure 12 in detail; and (5) on the waterfall structure itself. There are no large open plaza areas in this block, so its efficiency is considered to be 100 percent. This block enjoys year-round lunch hour sunshine, though during the winter the park is shaded partly by an office tower to the south until late morning. There are several such towers around the block, but they have very little cohesion and vary in mass between the towers and the lower structures, such as the building that directly faces the park. Hence the degree of enclosure in this block is dependent almost entirely on the form of the park,
*Note: References to areas in the photographs here and throughout the thesis are made in terms of the way one would view each photograph. For instance, "the left half" of figure 10 indicates the lower portion of page 68.

Figure 12
Waterfall Structure, 1700 Skyline
which is lessened by the lack of major changes in elevation, which characterizes the 1500 and 1600.blocks of Skyline Park.
Unlike the other blocks of the Park, this block has recently seen the placement of a high quality restaurant in the adjacent property, in the center of the blobk, thus giving it a high 'use generators rating. This restaurant has placed tables in its front 'court' area and served food and drinks .there during the summer, giving the park a crucial element of vitality. Housing, several restaurants, and hotel recently opened in adjacent blocks contribute to the cross-use of the park to a moderate degree. Use has been less than it ought to be, perhaps owing to the low density of the surroundings, but major projects in the area have recently been completed and others are getting closer to full development (such as the development adjacent to the 1600 block of the Park), so the level, of use should increase within a few years. Vendors apparently have found no justification as yet to operate here. The waterfall structure runs during the summer and fall and serves as the single major center of the block, because the re-

mainder of the block, on the left side of figure 10, consists mostly of the simple pathway bordered by lots of ledges and lawn areas. The other blocks have larger, amphitheatre-like plaza areas at each end.
The predominant feature of this block which distinguishes it from the other blocks of the Park, is its special emphasis on the lawn areas and the ledges that cross them. The water
feature, though lacking the feature that the others enjoy, of permitting a person to get inside, under and behind the water, has a particularly strong image, when operating, of a rushing mountain stream and an equally appropriate roar of water.
The area around the 'stream' has light fixtures that can make the park especially exciting in the evening. There are no
serious design flaws within the park, but the 'sidewalk' between the park and the buildings are exceedingly empty and blank, making the arcade of the 1500 block of the Park very much missed here. The poor interaction of the buildings with the park is emphasized by the reflective windows of the tower building, the parking garage and bank drive-through area in the portion of the building at the far right of figure 10, and the lack of any entries to the buildings directly along the park.
The upper plaza on the roof is almost entirely useless, although the restaurant has, in the summer, begun using its rooftop as an outdoor 'cocktail lounge' with music during the 'happy hour.'
The contrast of the tower with the lower buildings is extreme and gives the plaza no sense of enclosure, and the surrounding buildings have similar characteristics, further preventing any strong degree of enclosure in this park. The low level of use may be attributed to the newness of development in the area; the adjacent building is only three years old or so, and most of the other buildings in the area have been built since then.

The restaurant and its outdoor tables, on both levels, add greatly to the park's use and image, and should be encouraged. Development of commercial space, preferably for retail, in the garage area, would be an excellent complement to the restaurant and the park in general. Retailing should be introduced in the office tower, on the ground floor, as well. The new development projects in the area should generate many potential park users in the near future, but the uses in the block itself should be responsible for generating a good portion of those users.
In the park itself, the water element should be operated on a more year-round basis, and some staged events would be desirable. Possibly, a pedestrian bridge would be suitable across Arapahoe Street at the far right of the photograph in figure 10, to connect with the upper-level plaza in that block (Mountain Bell Plaza, the discussion of which follows).
Mountain Bell Plaza Figure 13
Descriptive Data and Ratings,
Mountain Bell Plaza
Square Feet: 30, 710 Interest:
Linear Feet of Seating: 440 Use Generators:
Concentration Use:
of Seating: Choice and 14.3 Food:
Variety: 4 Trees:
Efficiency: 96 % Plantings:
Visibility: Lawn:
Safety: Water:
Enclosure: Overall Design:
Centering: Surroundings:

Figure 14-
Overhead Photograph, Mountain Bell Plaza

Description Though this plaza has a very large number of planter ledges, which normally provide an excellent type of seating, most of these ledges are poorly situated for this purpose, thus giving it an unacceptable, though nearly adequate, concentration of seating. Seating choice is among: (1) the main plaza area shown partly on the left side of figure 14; (2) the small, highly enclosed area around the flag poles; (3) along the ramp area of the upper right of figure 14, and shown from its base in figure 15; and (4) the steps leading from the sidewalk up to the plaza. The efficiency is quite high, but the main plaza area is too broad. This plaza is on the whole completely out of sight for persons at street level, and the stairway and ramp do not provide views into the area, but instead appear to lead to the unknown. This aspect eliminates the street as a source of safety monitoring, which is further decreased in the flag pole area by the planters, which obscure it from both the general plaza area and the office build ing.
Office towers to the south and southwest of the plaza cause winter shadows on the main steps area and on the main
Figure 15
Ramp Area of Mountain Bell Plaza

plaza in the afternoon, but the sun is quite adequate until noon throughout the year. Except for the open side on the right of figure 1^, there is good enclosure from the other three sides, and the planters near the open side contribute to the spatial quality somewhat.
The plaza is centered effectively around the main plaza, and the sitting ledges on both sides of the steps are well-suited for people-watching, but there is no item of real interest such as a sculpture or water fountain. The generation of use of the plaza is quite weak, and depends almost entirely on lunch time users from the Mountain Bell offices. Restaurants and a few retailers on the interior malls of two neighboring 'megastructures' are too insignificant and isolated from the street to generate much traffic past this plaza. Use is generally high during the summer, in spite of the plaza's near invisibility, lack of interest and limited amount of afea diversity. A few special events in the summer raise the level of use to a really successful point.
A vendor is common on the street corner near the lower right in figure 1^, and though it is generally separate from the plaza by the difference in elevation, the base of these steps are a valuable part of this open space. The significant number of trees and plantings are clearly visible in figure 1^, as is the absence of lawn or a water feature.
This plaza has the least visibility of any of the fifteen major downtown plazas, and should suffer tremendously as a result of it. The retreat from the traffic that it provides apparently seems to encourage its use, especially by Mountain Bell employees, in spite of that problem.
Still, the elevation of the plaza out of sight of the person on the sidewalk, and the blank walls that are presented in place of a level plaza are very negative and discouraging to the more general public. This characteristic must be seen as a very serious design flaw which is and will remain as an

obstacle to the plaza's success. The problem of the plaza's lack of visibility, and absence of any water feature or other item of interest are design inaddequacies which are only partly offset by the landscaping, intricate seating patterns, and seclusion from traffic.
The block from which the photograph of figure 14 was taken, is in a 'megastructure' form and also has an upper-level plaza, which is connected to the Mountain Bell Plaza by a pedestrian bridge about a hundred feet to the left off of the photograph of figure 14. Unfortunately, the adjoining plaza has no usage or interest, and the Mountain Bell Plaza is obscured from the view from the bridge by the part of the building on the left of figure 14. An escalator that exists beneath that part of the building could bring many users into the plaza, but the informational graphics around the escalator's base are extremely weak. The sitting ledges along one side of the ramp that extends off the top right of figure 14 are good amenities, but there is nothing to keep one's interest, since the opposite side has a high wall obscuring the street view.
The blocks off the right and top of figure 14 are, respectively, a block dominated by parking and a block which has been recently developed, but remains largely vacant. They presently detract greatly from the density of the area, and as a result contribute no users to the plaza. The previously mentioned 'megastructureS' in the neighboring blocks also make little or no contribution to this plaza in terms of generating users.
The mysterious image of the plaza from the street level could be improved dramatically by replacing the corner planter at the bottom of the main stairway with steps only, or perhaps with much simpler plantings. A simpler, though less effective solution would employ appropriate graphics and signage at all

possible points of entry, of which there are effectively five: the main steps; the ramp; a side entry at mid-block off the left of figure 14; across the pedestrian bridge; and at the escalator. The introduction of a water element within the plaza, possibly falling from the top to the bottom alongside the main steps, or made visible by other means from the sidewalk, would present a much livelier image of the plaza, besides providing a needed amenity of interest. More variety of seating in the plaza would be appropriate, with benches, lawn areas converted from planter boxes, or possibly some heavy, movable chairs.
Beyond such design improvements, the development of more diversity within the block and in the area is essential.
Mountain Bell is not likely to have a restaurant or retail outlet placed in its building, but it does have a small display area that could be expanded into an electronics and communications museum, to give the block and its plaza wider public attraction. Retailing and restaurants would be most suitable, and more realistic for placement in the areas around the plaza which connects to the the Mountain Bell plaza by the pedestrian bridge. The block off the top of figure 14, which has been recently developed, has its own major plaza, and will not likely contribute many users to this plaza. But the eventual development of the block off the right of figure 14, preferably without a major plaza, would add to this plaza's potential for use. The simplest improvement for the plaza, however, would be the use of informative graphics around the plaza entries. Still, a water feature would be an effective attraction, and the opening up of the main entry with more steps would contribute enormously to the plaza's design.

higure 16
Overhead Photograph, Prudential Plaza

Prudential Plaza Figure 17
Descriptive Data and Ratings, Prudential Plaza
Square Feet: 46,800 Interest:
Linear Feet of Seating: 600 Use Generators:
Concentration Use:
of Seating: Choice and 12.8 Food :
Variety: 5 Trees:
Efficiency: 93 % Plantings:
Visibility: Lawn :
Safety: Water:
Enclosure; Overall Design:
Centering: Surroundings:
This is a combination of three different properties, only one of which, the portion at the left in the figure 16 photograph, is formally known as 'Prudential Plaza.' This area, a one-block section of the Sixteenth Street Mall, and a lawn and landscaped area along the building on the other side of the Mall, together form a single, major urban plaza.
The amount of seating is high, but because of the large size of the plaza, the concentration of seating is less than it should be. The choice of seating areas are: (1) on the lawn
or low ledge around it, at the right side of the figure 16 photograph; (2) on the benches in the Mall, near where the shuttle bus has stopped in the figure 16 photograph; (3) on the planter ledges and individual seats facing the Mall from the left of the photograph; (4) on the planter ledges or building ledge, facing each other, at the far left of the photograph; and (5) on individual seats around either of the two fountains in the Mall, shown in figure 18. The area of low

in the Mall, shown in figure 17, but which have no interest when not running and are small relative to the plaza as a whole.
Use is generated tremendously by the Mall and its shuttle vehicles, but in terms of land use, the plaza is bordered by office uses alone, and has retailing and restaurants only in nearby blocks and within the mall of the 'mega-structure' on the left of figure 16. The amount of use is quite high for the amount of seating provided, and though it has much less seating than Skyline Park, spread over an even larger area, the amount of people using the plaza is approximately equal to the level of use in the most successful of the Skyline Park blocks (1500 Skyline, just off the lower right corner of the figure 16 photograph. Two or three vendors in the plaza are common, and there are plentiful trees, plantings, lawn areas and a water element, to give the plaza a high level of amenities.
The general success of the plaza is a result of the very reliable sun, the substantial amount of seating, and the overall activity of the Mall. It has no complex design features, but has no major design flaws either, except for the low density of seating. The lack of continuous seating on the Mall and the emptiness of the wide sidewalk area between the Mall and the planter boxes are inappropriate wastes of valuable, sunny space. That absence of seating in close configuration around the main walkways, is the cause of the plaza's weak center.
The undeveloped land of the surface parking lot off the top left of the figure 16 photograph detracts from the potential for enclosure and from density and use generation.
The block off the bottome left of that picture, below and to the left of the photographer, is under construction (1600 Skyline), but its past and present lack of activity generation has not benefited the plaza. Though the Mall is largely a

retail corridor, there are no such uses facing this plaza, and there is only one major retail outlet in the immediate vicinity, off the top right of the figure 16 photograph.
Clearly, added sitting areas are both necessary and possible. It should still be recognized that these now inefficient areas can be put to temporary but valuable use for special programs, so perhaps any additional seating should be movable or arranged specifically for that purpose. Introduction of retail uses in the front of the building on the left side of the figure 16 photograph could add more vitality and function to the plaza, though the present ledge along the window, now a popular sitting space, would be sacrificed for the benefit of window shoppers.
In the surroundings, the development of the parking lot mentioned above may improve the degree of enclosure and generate more plaza users. A surface parking lot to the southwest, behind the building with the lawn areas by 200 feet, if developed intensely, may harm the amount of sun the plaza receives, but such development appears to be far from imminent. There will be some effect on the plaza from completed development of the project adjacent to the 1600 block of Skyline Park, but most of its users will be diverted into its own
plaza and Skyline Park.
Colorado National Plaza Description
This is the smallest of the fifteen plazas examined, but is one of the most successful spaces, and is actually bigger than it first appears. Besides the main plaza area between
<"* the parking lot and the building, the large planter ledge in
the left of the figure 19 photograph provides a long sitting ledge that extends along the narrow corridor towards the other side of the block. Most of the linear feet of seating in this plaza is along this ledge. The moderate quantity of

Figure 19
Overhead Photograph, Colorado National Plaza

Figure 20
Descriptive Data and Ratings, Colorado National Plaza
Square Feet: 10,460 Interest:
Linear Feet 250 Use Generators:
of Seating: Concentration Use:
of Seating: Choice and 23.9 F o o d :;
Variety: 3 Trees:
Efficiency: 100 % Plantings:
Visibility: Lawn:
Safety: Sun: Water:
Enclosure: Overall Design:
Centering: Surroundings:
seating and the plaza's small size combine to produce a good concentration of -seating. The choice of seating areas are: (1) in the main plaza area; (2) on the planter ledge facing the parking lot; and (3) on the planter ledge along the narrow corridor. The plaza is completely efficient, because
the open areas are not too large for the amount of pedestrian traffic flows, which come in and out of the plaza partly through an alley-like pedestrian passageway that goes off the right of the figure 19 photograph to a smaller plaza area. Neither the small plaza or the passageway that leads to it, shown in figure 21, are considered as part of this plaza, because the passageway is without any seating and the plaza is too small. Visibility of the plaza is fine from the street, and it has good self-monitoring capabilities, but the narrow corridor can be seen only from either end or from within it. Also, the main plaza is faced by a blank wall along one side, and the other building's reflective windows do not appear to present any means of crime monitoring in this plaza. Because of the surface parking, which
covers about half of this block, and the moderate height of

8 5
Figure 21
Large Pedestrian Passageway in Colorado Nartional Plaza
buildings on the south, southwest and southeast, there is a steady amount of sunshine all day long and all year round. Except for the narrow corridor, this plaza has virtually no sense of enclosure, due to the parking lot. Because the seating on the two sides of the main plaza area is broken up into separate benches, loosely grouped, and because the -narrow corridor has a ledge along on 1y one side, the qua!ity of centering is weak. There is no element of interest here, but people seem attracted to the plaza's sun and informality.
The parking lot does not qualify as a use generator, and there are only office uses in the adjacent buildings, but ther.e are retail uses and restaurants in nearby blocks, especially along the Sixteenth Street Mall, which is across the parking lot. The Mall itself does not appear to generate many users of this plaza. Use is very high along the large planter ledge, and the conventional benches are always full on a sunny day during the lunch hour. Food vendors are always at least a half block away. Trees and plantings are

plentiful, but there is no lawn or water element.
The success of this small plaza leaves little room for criticism of its design, but there are other problems which limit its use, particularly the amount of seating around the main plaza area. Though this limited seating capacity may
well be one of the plaza's attractions, because it gives the users an uncrowded, relaxed social environment, the seating could still be increased. The larger passageway in figure 21 has a very pleasant quality of enclosure and quietude, and it would easily be considered an extension of the plaza if it contained a series of benches similar to those in the main plaza area.
The narror passageway, which serves an amount of people certainly equal to the amount using the larger passageway, is an excellent place, but seems too narrow and less exciting because it has the sitting ledge along only one side of it.
The junipers which line that ledge are quite overgrown and eliminate sections of that ledge for sitting, as well as obscuring the view into it from the rest of the plaza. This area has a quite high level of enclosure while retaining good amounts of sun.
The parking lot, which is a general scar on the quality of the plaza's environment and surroundings, eliminates the sense of enclosure that a building would create, besides failing to generate any substantial numbers of potential plaza users. However, the amount of use would suggest that the parking lot does not deter people from using the plaza. Because of the high efficiency of the plaza, the
lack of a sculpture or water element is not a serious problem.
In terms of design, this plaza merely needs added benches, distributed moderately on a minimum of two sides

of each of the box planters. Such seating in the large passageway would extend greatly the size and general enjoyment of the plaza. Development of the parking lot, is probably the most critical to improving its degree of enclosure, though it would most likely eliminate its continuous sun. Any new development should extend the pathway of the large passageway toward the Sixteenth Street Mall, and if at all possible, line it with retail shops appropriate to the Mall. The new development should have a major entry through the plaza, possibly with its own extension of the plaza, which could be the best side for a sculpture or water feature. It could certainly exploit in some manner, with great effectiveness, the great numbers of people passing through the center of this block by way of this plaza.
Denver Center for the Performing Arts
Figure 22
Descriptive Data and Ratings, DCPA Galleria
Square Feet: 77,600 Interest:
Linear Feet of Seating: 270 Use Generators:
Concentration Use:
of Seating: 3.6 Food :
Choice and
Variety: 4 Trees:
Efficiency: 59 % Plantings:
Visibility: Lawn:
Safety: Water:
Enclosure: Overall Design:
Centering: Surroundings:

Figure 23
General View through the DCPA Galleria

Filling the space of two streets for an equivalent of over two city blocks, this plaza, or pedestrian-only mall, is the largest open space in the downtown, within the thesis study area. In spite of its great size, it has as much conventional seating as two average downtown blocks, or i/i general, an extremely low concentration of seating. The selection of places to sit, however, includes: (.15 on the steps or walls near the street, shown by figure 24; (2) on
the steps or walls in the foreground of the figure 23 photograph and in front of the sculpture in the center of that
Figure 24
Fourteenth Street Entry to DCPA Galleria
Figure 25
Southwest View from DCPA Galleria

Figure 26
Northwest View through DCPA Galleria
photograph; (3) on the steps at the far 'back' of the plaza, facing the park space in figure 25; and (4) on the conventional benches that ring the sculpture. This plaza has the lowest efficiency in the use of space of all the downtown plazas, which is only rarely improved by special events.
The plaza is visible from the street only at the point shown in figure 24; most of the area around the sculpture, which covers Thirteenth Street, is not visible from the street level. The area around the sculpture, and along the parking garage, shown in figure 26, is monitored somewhat by a small office in the parking garage at piaza level, and by personnel in the theatre and concert hall buildings at the left in figure 26. But the area under the glass arcade is, in effect, bordered by blank walls and does not benefit from any surveillance from adjacent buildings, though it can be seen from the street.
Because of the height of the buildings around the plaza, which creates a moderate urban canyon, the winter sun reaches

most of the plaza for less than two hours a day. The glass arcade, however, is an excellent sun filter in the summer.
And in spite of the overhead enclosure it provides, the plaza is open to the horizon in three directions away from the sculpture, so it cannot be considered as a highly-enclosed plaza. The plaza does have a strong center around the sculpture, especially because of its placement at the natural center of the plaza, but the seating is far too little and is not amenable to people-watching because it all faces outward from a single point instead of across a central point. This sculpture is the central element of interest, but the galleria 'roof' and the overall architecture, and even parts of the plaza pavement, are fascinating qualities of the space.
The uses which are directly accessible through the plaza are generally entertainment uses only, though including the diversity of a symphony hall, a theatre complex, a cinema and a small sports arena. The massive parking garage which occupies an entire block, at the right of figures 2A and 26, does not contribute users in a way that could be considered as a source of plaza users. The surrounding land uses, near Fourteenth Street, however, includes retailing, restaurants, housing, a hotel, offices, a university campus, and a convention center. The office density, though, is very low, so there is little lunchtime use, but this is mostly the result of inadequate seating. The only time the plaza is really well-used is in the evening, and these people use it quite briefly for queuing and getting fresh air at intermissions. There are no vendors, either at lunch time or in the evenings. The plaza is entirely without trees, plantings, lawn or water, as can be seen in figures 23 through 26.
This plaza has extremely serious problems of design and, to a lesser extent, of the design and land use characteristics of the surroundings. The lack of trees and other natural

elements gives the plaza, especially because of its relative immensity, a very sterile and unnatural feeling. The tiny amount of conventional seating is a major reason for the low level of lunchtime use, but the arrangement of the steps and walls counted as sitting space does little to encourage peoplewatching. The dust and dirt on the steps, and the generally uncomfortable height of the walls (3 \ feet) are also uninviting. Most people, particularly the well-dressed crowds of theatre- and symphony-goers, prefer a clean, comfortable sitting bench or ledge, especially when it allows them to watch other people, and is distinguished from the city by a closeness to natural vegetation.
The density of activity in the surroundings is not extremely high, but it is adequate to give this plaza far greater use throughout the day. Students from the university, residents of the apartment complex, and to a lesser degree, office workers and shoppers are nearby, and have need for use of the plaza at many times during the day, but appear to be without good reason for spending much time in this plaza.
The ground floor of the parking garage facing the plaza contains commercial space, and the steel frame on the left in the photgraph in figure 23 is planned as a small office building. But while these are, respectively, vacant and undeveloped, the plaza is severely limited in the amounts of people and time they appear in it. Its greatest time of use which is in truth a vibrant and wonderful time, is before the evening performances, between about 7:30 and 8:30 P.M.
While the daytime appearance of the buildings to the sides of the covered plaza area, as shown in figure 23, has partly the image of an oil refinery, the nighttime lighting puts special emphasis on the stairs along the parking garage, and creates a quite pleasant effect.
Of all the downtown plazas, this one has possibly the greatest need for new design features. It needs drastic

improvements in seating, and the addition of trees and plantings is essential. These improvements must be simultaneous and wel1-integrated. Seating must be dense and directed at people-watching, along each side of the plaza. Public, fixed seating may best be concentrated along the left side of the photograph in figure 23, and around the sculpture, if outdoor restaurant tables are provided in good quantities along the commercial space units in the parking garage. Occupancy of the commercial space, by a mixture of retailers and restaurants, or even office uses is very critical too, but the absence of seating and vegetation must be resolved as well, coordinated with commercial development. These should have a higher priority than the proposed extension of the galleria covering, though that may add further excitement to the center. But perhaps even development of the office space in the steel framework would do far more to extend the life of the plaza, and should get more consideration than the galleria covering.
Currigan Plaza
Figure 27
Descriptive Data and Ratings, Currigan Plaza
Square Feet: 33,250 Interest:
Linear Feet of Seating: 1300 Use Generators:
Concentration Use:
of Seating: Choice and 39.1 Food :
Variety: k Trees:
Efficiency: 87 % Plantings:
Visibility: Lawn:
Safety: Water:
Enclosure: Overall Design:
Centering: Surroundings:

Figure 28
Overhead Photograph, Currigan Hall Plaza
9 A-

Figure 29
Entry Steps, Currigan Plaza
The tremendous amount and concentration of seating in this fairly large plaza is provided by the extensive series of planter boxes with good sitting ledges around each. The fountains and pool on the right hand side of the figure 28 photograph, are surrounded by a good sitting ledge, and steps at the front of the convention hall, shown in figure 29, are also fairly well used. The selection of sitting areas is among: (1) on the pool ledge or planter box ledges facing it; (2) on the steps, which face the central open plaza area; (3) on the lawn or planter ledges around the mirrored sculpture in the upper left of the figure 28 photograph; and {A-) on any of the other planter ledges distinctly separate from either the pool or the sculpture. The central plaza area is an inefficient area that is generally too wide for normal pedestrian traffic.
The plaza is fully visible from the streets, which surround it on three sides, and it has good self-monitoring capa-

city, but the building itself does not provide regular observation of the plaza, thereby reducing its safety level.
In the winter, the sun shines on most of the plaza only in the early morning, and on a small amount,of it (along the street in the foreground of the figure 28 photograph) during the remainder of the day, because the plaza is on the north east side of the convention hall. Another building, part of the Denver Center for the Performing Arts, off the right of the figure 28 photograph, casts some late afternoon shadows on the plaza, but establishes a good plane of enclosure. But there is little sense of enclosure in this plaza because of the surface parking across the street in the lower left corner of the overall photograph in figure 28, and because of the insubstantial height of the buildings in the upper left of that photograph.
The plaza lacks a strong single center, though the central plaza area, the sculpture, and the pool, provide moderate opportunities for people-watching. The center, as stated above, is too wide, and the sculpture and pool, which provide the interest for the plaza, are separated from the natural center, and they compete against each other, emphasizing the division of the plaza into two halves. The planter ledges around them are also spaced apart from each other, thus limiting the number of people who can sit facing these competing 'stages.'
The convention hall is limited entirely to the one use, but the surroundings are fairly diverse and generate many of the plaza users. However, the density of that diversity, is very low, especially to the southeast of this block, to the left off of the figure 28 photograph. The amount of office uses in the area is very low, so the lunchtime use is limited, but the diversity of the area keeps a steady trickle of users or at least passersby around the plaza throughout the day, into the evening, and on weekends. Vendors are not known to be near or in this plaza. Trees and plantings are clearly