Quantifying Urban Diversity: Multiple Spatial Measures of Physical, Social, and Economic Characteristics - Computational Approaches for Urban Environments - page 145

“New Urbanism” has been a motivating force. New Urbanism can trace some of its
concepts to the work of Jane Jacobs. In perhaps her most influential work The Death
and Life of Great American Cities , Jacobs focuses on what she describes as the four
generators of urban diversity. These are a fine-grained mix of primary uses; short
block lengths; a fine-grained mixing of building age; and sufficient dwelling density
to support urban vibrancy (Jacobs 1992 , pp. 150-151). Many of these elements have
been incorporated into the design principles of New Urbanism, leading to a push for
the design of “livable” urban spaces.
In the Charter of the New Urbanism, the Congress for the New Urbanism states,
“we stand for the restoration of existing urban centers and towns within coherent
metropolitan regions, the reconfiguration of sprawling suburbs into communities of
real neighborhoods and diverse districts, the conservation of natural environments,
and the preservation of our built legacy” (Talen 1999 ). The Charter goes on to
embrace each of Jacobs' four generators, stating that “neighborhoods should be
compact, pedestrian-friendly, and mixed-use”; “interconnected networks of streets
should be designed to encourage walking, reduce the number and length of
automobile trips, and conserve energy”; “appropriate building densities and land
uses should be within walking distance of transit stops, permitting public transit to
become a viable alternative to the automobile”; and “preservation and renewal of
historic buildings, districts, and landscapes affirm the continuity and evolution of
urban society” (Talen 1999 ). With such clear adoption of Jacobs' ideas, it is easy to
see why Jacobs' body of work remains a relevant topic of research.
Increasingly there is a movement among federal, state (provincial), and local gov-
ernments to invest resources in the interest of creating more “livable” environments.
While there is latitude as to what precisely constitutes a livable urban space, most
definitions include at least three of Jacobs' generators of urban diversity, namely,
dwelling density, short (or frequent) blocks, and mixed primary uses. Often, it is
clear to those that are familiar with the many communities within a city which
locations need the greatest investment in one or all of these generators. Policy-
makers must be able to present these decisions in a defensible manner to the
public at large. The justification for these decisions is often presented though a
qualitative analysis. While the qualitative approach to such work holds great value,
and Jacobs' work was almost exclusively qualitative in nature, the key elements that
she describes are quantifiable. This chapter seeks to quantify the four generators
that Jacobs describes in the form of a single index and four sub-indices in order to
permit a quantitative analysis of the livability of different communities within an
urban environment; here, Washington D.C. has been chosen as a case study.
While there has been considerable research into one or more of Jacobs' four
generators of diversity, as shown in the following section, there does not appear to
be research that has considered all four dimensions in combination. Furthermore,
nearly all research have been conducted using boundaries that do not necessarily
reflect areas that constitute a neighborhood or have been conducted at too coarse
a level of detail (such as an entire Metropolitan area). In addition, the existing
research has largely been conducted in suburban locations, rather than true urban
environments. In her introduction, Jacobs clearly states that “I hope no reader will