Description
Discuss the importance of the built environment, including place design and management, in reducing crime. Make sure you draw from the three assigned readings to discuss community design, public transportation locations, and bars. Use the attached articles to answer question.
Unformatted Attachment Preview
John MacDonald
Community Design and
Crime: The Impact of
Housing and the Built
Environment
ABSTRACT
Crime is influenced by the built environment. Broken windows, crime
prevention through environmental design, situational crime prevention, and
economic theories of the supply of and demand for criminal opportunities
offer explanations. Zoning, designs of streets and housing, locations of public
transit, and land uses shape the built environment in ways that can increase
or reduce crime. Cross-sectional research shows that elements of the built
environment are associated with crime rates in particular places. Quasiexperimental studies show that changes in zoning and street configurations,
configuration and design of housing, and access to public transit can help
manage crime. The mechanisms by which such changes influence crime are
not well understood, though shifts in the supply of criminal opportunities
most likely play a role. This evidence is promising. It suggests that the
built environment can be modified to reduce both crime and reliance on
criminal justice sanctions. Place-based experiments that manipulate features
of the built environment will provide evidence for policy makers to use in
designing cities in ways that reduce crime.
The idea that place matters in shaping social relations and crime has a long
history. André-Michel Guerry and Adolphe Quetelet were among the
Electronically published July 30, 2015
John MacDonald is professor of criminology and sociology at the University of Pennsylvania. He is grateful for comments on earlier drafts from the editor, Michael Tonry, and
q 2015 by The University of Chicago. All rights reserved.
0192-3234/2015/0044-0011$10.00
333
334
John MacDonald
first to connect crime and place empirically in their nineteenth-century
analyses of statistical data in France. Work in England attempted to explain variations in crime rates between and within cities during the nineteenth century (Weisburd, Groff, and Yang 2012). Most of this work was
descriptive and offered theories as to why crime rates varied from place
to place but did not attempt to provide guidance on how to curb crime.
By contrast, Snow’s (1849) early work in England on the causes of cholera
in contaminated drinking water during the nineteenth century noted the
importance of the spatial environment in shaping human health and suggested the separation of sewers and drinking water wells to prevent waterborne diseases.
The focus on descriptive theory continued in the early twentieth century with the development of the Chicago school of human ecology, which
argued that the urban form was important in shaping crime, mortality, and
morbidity rates (Taylor 2001; Sampson 2012; Weisburd, Groff, and Yang
2012). Urban planners later largely discredited the ecological school for
suggesting that cities grew in a natural evolutionary process and that there
was “free competition for space among users” (Logan and Molotch 2007).
Urban planners argued that places could be designed to affect human
interactions and that cities did not grow in any natural way.
Since the 1960s a literature has developed that explains how the built
environment affects crime. In urban planning, Jane Jacobs’s The Death
and Life of Great American Cities (1961) is the most influential work.
She theorized that specific features of the built environment generate
more or fewer “eyes upon the street” that in turn influence crime. She
advocated mixed land uses that generate more foot traffic and building
designs with closer setbacks from sidewalks to maximize sight lines to
the street.1 Urban planning scholar Schlomo Angel (1968) argued that
commercial strips in Oakland, California, had higher crime rates than
other commercial areas because of reduced foot traffic and increased vulnerability of would-be victims. Oscar Newman’s Defensible Space (1972)
also noted the importance of the physical design of places in relation to
anonymous reviewers, and for helpful discussions with James Anderson, Charles Branas,
and Charles Loeffler on the topics covered in this essay.
1
In an early effort, Fowler (1987) examined one of Jacobs’s core ideas about land use
diversity and reported crime. She examined 19 areas of two to three city blocks in Toronto
in which she sought to maximize land use diversity differences. The sample was too small
to generate meaningful p-values.
Community Design and Crime
335
crime. Criminologists have developed these ideas in theories of crime prevention through environmental design (CPTED; Jeffery 1971) and situational crime prevention (Clarke 1995). More recently, public health
scholars have paid increased attention to ways the design of communities
affects crime, drawing on the literatures in urban planning and criminology (Mair and Mair 2003). Multiple fields now recognize that the built
environment affects crime. A growing literature demonstrates that political decisions about how and where to invest public resources have fundamental influence on the urban form (Sampson 2012).
In this essay, I review literatures from criminology and urban planning to illustrate features of the built environment that are associated
with crime. Extensive reviews on the criminology of place can be found
elsewhere (Reiss and Tonry 1986; Kirk and Laub 2010; Sampson 2012;
Weisburd, Groff, and Yang 2012). My goal is to connect theories of the
criminality of place to understanding of how different features of the
built environment affect crime. I build on an earlier Crime and Justice
essay by Taylor and Gottfredson (1986), who provided a theoretical framework for explaining how offender cognition of neighborhood physical
structures shapes crime in neighborhoods, street blocks, and specific sites.
They also described cross-sectional evidence from the early 1980s on associations between features of the built environment and crime. I emphasize
quasi-experimental studies.2
Policy guidance on design of the built environment to reduce crime
has been based on case studies or cross-sectional evidence (Taylor and
Harrell 1996; Zelinka and Brennan 2001; Cozens 2008; Cozens and
Love 2009; Paulsen 2013). Case studies often examine changes in the
built environment and crime in a single location, thereby providing little
basis for examining whether changes could have occurred by chance.
Cross-sectional studies provide statistical tests of chance differences but
have the fundamental problem of being unidentified: multiple variables,
both observed and unobserved, could explain the same distribution of
crime. This is a problem with all observational studies and a primary reason for reliance in economics on quasi-experimental methods (Angrist
and Pischke 2008). Quasi-experimental studies rely on plausible sources
of random variation and attempt to approximate an experiment in which
2
The best causal evidence would come from large-scale randomized controlled trials of
changes in the built environment and subsequent changes in crime. I have not located any
(see Welsh, Braga, and Bruinsma 2013).
336
John MacDonald
groups are randomly assigned to receive treatment or control conditions.3
Quasi-experimental studies provide stronger evidence.
There are myriad ways the built environment of places could be modified to reduce crime and reliance on criminal justice processes. First,
evidence generated from structural changes to the built environment that
are scalable and sustainable may be more amenable to policy interventions
than are individual-based interventions that are difficult to implement
en masse, expensive to maintain, and hard to replicate elsewhere (Branas
and MacDonald 2014).
Second, changes to the built environment, such as adoption of new
building or zoning codes, can be made through a regulatory framework
without use of the criminal justice system. Current criminal justice policies are exceedingly expensive—about 7.9 percent of all local government
spending (Kyckelhahn 2013). Trade-offs between expenditures on planning and on criminal justice should inform development of policies for
shaping the built urban environment. Focusing on changing the built
environment to reduce crime avoids the “causal fallacy” of thinking that
crime can be reduced only by eliminating its root causes (Wilson 1983,
p. 47).
A number of conclusions can be drawn. First, zoning of land to encourage mixing of residential and commercial uses reduces crime in commercial areas. Second, street configurations that reduce permeability of cars,
such as cul-de-sacs, appear to reduce crime. Third, public transit is associated with crime in places, but research findings suggest that the opening
of transit either has no effect on crime or reduces it by spurring economic
development. Fourth, construction of public housing that concentrates
poor people in segregated neighborhoods generates crime; low-income
housing vouchers have little effect on crime. Fifth, mixed-income housing
development may reduce crime compared with public housing development. Sixth, abandonment of housing due to economic distress appears
to increase crime, but securing vacant housing appears to reduce it. Seventh, cleaning and greening vacant properties appear to reduce crime.
Eighth, land uses related to alcohol, such as bars and alcohol outlets,
may be associated with crime, but we lack strong evidence that they increase crime in areas over and above other existing risk factors. Ninth,
although schools have been hypothesized to generate crime in places,
3
In economics the term “exogenous variation” is used to refer to variation in variables
of interest from outside of the model that are not correlated with confounding variables.
Community Design and Crime
337
the evidence is weak. Quasi-experimental evidence suggests little relationship between crime in neighborhoods and the opening and closing of
schools.
Quasi-experimental studies of the effects on crime of changes in the
built environment have occurred only in a limited number of settings.
Much more research should be done in different contexts to provide
guidance to policy makers. Researchers should capitalize on natural experiments in which land is rezoned, housing is built or remediated, and
public transit systems are developed or altered. Place-based experiments
can be designed anywhere policy makers are considering changes in zoning or land use configuration.
Here is how this essay is organized. Section I examines data on the spatial concentration of crime and theories that attempt to explain how the
built environment affects it. Sections II–V consider different features of the
built environment that matter, including zoning, street design, public transit, housing design and configuration, and land use patterns. Section VI
considers next steps for efforts to facilitate the design of safer cities.
I. Spatial Concentration
The severity and rates of crime vary greatly by time and location. In 2012,
the 20 largest American cities’ police agencies reported 3,110 murders,
21 percent of the 14,827 reported nationally. Only 10.79 percent of the
population, however, lived in those cities.4 Both official police data and victimization reports document higher crime rates in bigger cities (Glaeser
and Sacerdote 1999). Within cities, crime is highly concentrated in specific
neighborhoods and city blocks. Concentrations of street crime are greater
in given blocks than among arrested individuals (Sherman 1995). Low-crime
neighborhoods can become higher-crime neighborhoods (Schuerman and
Kobrin 1986), sometimes reflecting patterns of gentrification of neighborhoods surrounded by poverty-stricken areas (Taylor and Covington 1988;
Covington and Taylor 1989). Crime drops in cities occur mostly within a
small fraction of city blocks (Weisburd, Groff, and Yang 2012). The hyperconcentration of crime in cities suggests that the criminality of place may
be as important as the criminality of individuals in thinking about policy
options to reduce crime.
4
Author’s calculations from Uniform Crime Report data (http://www.bjs.gov/ucrdata
/Search/Crime/Crime.cfm; accessed February 17, 2014).
338
John MacDonald
A. The Built Environment of Places and Crime
Crime is correlated with specific features of places. Areas plagued by
crime tend also to have high rates of vacant or dilapidated housing, high
residential turnover, unsupervised youths, poorly lit streets or poor visibility, highly permeable access to streets, and land uses such as liquor stores
that generate crime (Skogan 1990; Weisburd, Groff, and Yang 2012).
Municipal codes governing building, occupancy rules, street design,
and transit shape cities in ways that affect crime. Policy makers directly
control municipal laws and rules and could, if they wished, use scientific
knowledge to regulate the built environment to minimize crime. Extensive research shows associations between different aspects of the built
environment and crime. This section summarizes classic cross-sectional
and more recent quasi-experimental studies that show how changes in
the built environment affect crime.
B. Different Mechanisms That Explain Why the Built Environment Matters
Why is crime concentrated in areas with specific features? Concentrated poverty is one reason. It is correlated with poor housing stock
and land uses that attract crime. Poverty contributes to social and behavioral problems that make crime an intrinsic feature of poor areas. For
example, poor individuals may be more consumed by worries, hunger,
and stress that impair cognitive functioning (Mani et al. 2013). Poor
families may be less able to engage in effective parenting practices that
teach children to self-regulate. This is important because crime and
other negative life outcomes are correlated with low self-control (Moffitt et al. 2011). Individuals living in poverty-stricken areas may be more
likely than others to commit crimes because the expected benefit exceeds
that from alternative legitimate wage-earning activities (Becker 1968).
Endemic poverty may create or sustain cultural norms in which crime
is seen as a legitimate method of economic gain and violence a socially
appropriate response to insults or personal affronts (Anderson 1998).
Poverty may lead to breakdowns in informal social controls that impede
crime (Shaw and McKay 1942; Sampson 2012).
The poverty-crime explanation is plausible or persuasive to many people, but by itself it is too simple. Even in poor neighborhoods, crime is
highly concentrated on specific blocks with specific features. More fundamentally, areas of relative wealth can have relatively high crime rates
when features such as the presence of shopping and entertainment areas
create attractive criminal opportunities (Brantingham and Brantingham
Community Design and Crime
339
1995; Bernasco and Block 2011). Several prominent theories attempt to
explain how the built environment affects crime.
1. Broken Windows. Wilson and Kelling’s (1982, p. 29) broken windows theory explains that signs of blight and disorder in the built environment signal that an area is uncared for and thereby engenders crime.
They observed, “Untended property becomes fair game for people out
for fun or plunder. . . . Vandalism can occur anywhere once communal
barriers—the sense of mutual regard and the obligations of civility—
are lowered by actions that seem to signal that ‘no one cares.’” Physical
and social disorder neighborhoods tell motivated offenders that crime
goes unabated.
Several studies suggest a connection between crime and disorder.
Skogan’s analysis of survey data from Atlanta, Chicago, Houston, and
Newark showed that levels of disorder were more correlated than other
social and economic variables with robbery victimization in neighborhoods (1990, p. 75). Taylor and colleagues found that reported crime in
Baltimore and Philadelphia neighborhoods, and residents’ fear of crime,
were correlated with observable signs of blight and disorder on city blocks
(Taylor, Shumaker, and Gottfredson 1985; Perkins and Taylor 1996).5
Sampson and Raudenbush (1999) found that observed measures of physical disorder on street blocks in Chicago neighborhoods, such as garbage in the street, were correlated with self-reported violent victimization
and crimes reported to the police.6 However, when they controlled for
measures of neighborhood collective efficacy, land use, concentrated poverty, and other factors, they found only an insignificant association between observed disorder and self-reported household victimization. Only
5
Correlations between observed physical disorder and these outcomes were relatively
weak and were strongest on blocks in moderate-income neighborhoods. This suggests that
disorder and crime are linked to underlying poverty conditions. Perkins and Taylor’s
(1996) survey of low-rise housing residents in Baltimore neighborhoods at two times
found a small but significant correlation between observed physical disorder ratings of randomly sampled households and reported fear of crime, controlling for perceived social and
physical disorder by residents and basic demographics. These results suggest that residents
on blocks with more blight have a higher fear of crime, even after taking into account
individual differences in perceived disorder.
6
They also include measures of social disorder calculated by adults loitering or congregating, drinking alcohol in public, peer groups with gangs present, public intoxication,
adults fighting or arguing, selling drugs, or prostitutes on streets. With the exception of
adults loitering or congregating (5 percent of blocks), the prevalence of observing social
disorder was less than 1 percent of blocks observed (Sampson and Raudenbush 1999,
p. 618), indicating that the scale mostly measured physical disorder.
340
John MacDonald
police-reported robbery rates remained significantly associated with disorder after they controlled for collective efficacy and neighborhoods’
prior crime rate. They suggest that disorder is correlated with crime,
but neighborhood collective efficacy mediates its influence.
The fundamental problem with cross-sectional studies of disorder and
crime is that measures are collected together and are endogenously related. Only a series of small-scale field experiments in the Netherlands
has found strong evidence that physical disorder encourages other forms
of disorder and minor offending (Keizer, Lindenberg, and Steg 2008).7
Debate continues about the causal mechanisms by which disorder may
lead to crime (Harcourt 2001; Harcourt and Ludwig 2006). Broken
windows theory provides one candidate mechanism.
2. Crime Prevention through Environmental Design. The CPTED
theory suggests that features of the built environment make places more
or less attractive to would-be offenders ( Jeffery 1971). Such features include poor visibility, unguarded opportunities, and permeable streets
that make it easy to escape detection or apprehension. Densely populated
buildings, for example, may be located on networks of short streets that
are conducive to crime because they provide poor visibility. Thoroughfares between neighborhoods may provide relatively more permeable
streets that allow easy access to and escape from crime. Features of places
that make them more or less amenable to crime include the level of natural
surveillance, access control, target hardening, and signs of territoriality
(Cozens, Saville, and Hillier 2005).8 Newman’s (1972) work on defensible
space makes similar points.9 According to CPTED, the built environment
influences crime in the ways it shapes criminal opportunities for motivated offenders.
7
In one field experiment, adding graffiti to a wall next to a “no graffiti” sign where bicycles
were parked doubled the prevalence of littering (throwing on the ground a flyer that had
been placed on bicycles) compared with the control condition when no graffiti were present.
In another experiment, graffiti were placed on a mailbox from which a clearly visible €5 bill
protruded from an envelope; individuals were more likely to steal the letter when the mailbox
bore graffiti. Another experiment found that bicycles illegally locked to a fence increased the
likelihood that people would cut through an area marked “no trespassing.”
8
Key concepts and findings of CPTED are examined elsewhere (Cozens, Saville, and
Hillier 2005).
9
Newman makes clear that his ideas about defensible space architecture are more germane to poor areas in which families have fewer resources to hire doormen and take other
protective measures than where there are more stay-at-home parents and people have other
resources at their disposal.
Community Design and Crime
341
3. Situational Crime Prevention. Situational crime prevention provides
a theoretical framework for explaining how features of the built environment affect crime (Clarke 1995). Situational crime prevention is often
linked to routine activities theory, which proposes that crime is a product
of motivated offenders, suitable targets, and the absence of capable guardians (Cohen and Felson 1979). The built environment can influence crime
by shifting the availability of suitable targets and capable guardians. Designs of areas that facilitate less anonymity and more ownership may enhance guardianship and persuade motivated offenders that an area is a less
attractive target (Newman 1972). Similarly, situational crime prevention
posits that crime rates depend on the ease with which motivated offenders
recognize criminal opportunities. Hardening potential targets by use of
security systems and other efforts will deter would-be offenders. Criminal
behavior is influenced by “variations in opportunity and transitory pressures and inducements” (Clarke 1995, p. 95). The built environment shapes
immediate or situational contingencies or opportunity structures that lead
motivated offenders to decide whether to commit a crime.
This model provides a solid framework for thinking about how features
of the built environment shape criminal opportunities. It suggests that
structural changes can influence both choices of targets (e.g., convenience
stores, banks) and facilitators of crime (e.g., drugs, alcohol; Clarke 1995,
p. 103).
4. The Supply of and Demand for Criminal Opportunities. Cook (1977,
1986) links economic theory to situational crime prevention and CPTED
by arguing that the supply of criminal opportunities affects crime. Situational crime prevention can easily be adapted to an economic framework
by connecting changes in the physical environment to supplies of victims
(e.g., strangers) and crime targets (Clarke 1995, p. 103). Cook uses a supply and demand model to show how changes in the supply of crime opportunities should result in additional effort to commit crimes. Shifts in the
supply of attractive targets should also affect the demand for crime (Cook
1977, 1986). Figures 1A and 1B illustrate how shifts in the supply of criminal opportunities shape demand for crime. The crime rate is a product
of the supply of opportunities and payoffs from crime. As the supply of
potential victims decreases, there will be some updating from motivated
offenders, so that the reduction in payoff from any given intervention will
be offset by additional effort. Figure 1A shows a traditional supply and demand framework. The y-axis is the payoff (P) of committing an offense
and the x-axis is the quantity of crime (Q). At one equilibrium there is a
342
John MacDonald
FIG. 1.—A, Elastic demand for crime: economic model. B, Inelastic demand for crime: situational crime prevention model.
given supply schedule for criminal opportunities (S). A shift in the built
environment that makes crimes more difficult may cause the overall payoff from crime to move downward. This is shown in the leftward movement from D1 to D2.10
10
I thank Emily Owens for helping me figure out how to express these ideas.
Community Design and Crime
343
For illustration, imagine that a change in street parking rules, allowing
only people with permits to park in a given neighborhood, causes a 20 percent downward shift in the payoff from breaking into cars. The parking
regulation change may mean that fewer cars will be parked on the street.
If people with a permit are more likely to live in the neighborhood and less
likely to leave valuables in their cars, the average payoff from breaking
into a car will go down. This means that the market price for breaking
into a car will result in a lower overall rate of victimization reflected in
the change from Q1 to Q2.
Some individuals, however, will still break into cars even if they expect
a lower payoff. This means there is some elasticity to the demand for
crime among motivated offenders. Therefore, a 20 percent decrease in
the payoff will result in some lower threshold of crime reduction. A
realistic benchmark might be a 6 percent reduction reflecting a demand
elasticity of 0.3. The key insight is that shifting the supply of criminal
opportunities also affects the demand for them, but this will not be
reflected in a complete 20 percent reduction in theft from cars.
The installation of ignition immobilizers in recently manufactured
automobiles provides another example (Cook and MacDonald 2011).
The price of stealing a car will increase as cars become more difficult
to steal; those without immobilizers will be older, less valuable models.
As Cook’s (1986) model envisions, individuals who want to keep stealing
cars will have to take greater risks. This means that there will be some replacement and that the demand for crime will not fall in exact proportion
to the increase in the difficulty of car theft. People who really want to steal
a car will try harder: they will steal cars even with a lower expected payoff.
By contrast, proponents of other theoretical perspectives argue that
demand is inelastic relative to the supply of criminal opportunities; motivated offenders will continue to seek opportunities and substitute other
crimes. This is shown in figure 1B.
Assume that a change in the built environment of a place, such as a new
building requirement for installation of improved window locks (Katyal
2002), makes it 20 percent more difficult to break into newer homes. Under this model, the overall supply of newer homes to burglarize will shift
downward. The demand for crime will be the same, but burglars will have
to work harder for the same payoff. This model is consistent with CPTED,
which assumes that the supply of motivated offenders is constant and
that only shifts in the supply of opportunities (S ) determine the amount
of crime (Q).
344
John MacDonald
It is possible that shifts in supply through changes in the built environment could change the payoff from crime at every point of the demand
for crime, but this does not seem plausible. Changes in criminal opportunities associated with changes in the built environment are unlikely to
affect all crimes equally. It seems unlikely that criminals are completely
inelastic, even if some individuals with extremely low impulse control may
be less sensitive than others to changes in payoff prices.
Deciding which model is better is not my aim. The important point is
that shifting the supply of criminal opportunities in places by changing
the built environment can reduce crime overall without addressing underlying criminal propensities.
C. Summary
Crime is spatially concentrated. Physical features of places play some
role in its generation. Broken windows, CPTED, situational crime prevention, and economic opportunity theories all propose mechanisms for
explaining how changes in the built environment might affect crime.
Changing the built environment to reduce crime does not necessarily
imply that crime will fall absolutely; displacement to other targets and
places is possible. Sensible changes can make crimes harder to commit
for the marginally motivated offender. Less motivated offenders may
stop committing certain crimes because opportunities are less available
and payoffs are not as good. CPTED and situational crime prevention
perspectives provide a basis for thinking about how the target richness
of an area influences criminal offending. Broken windows theory suggests that changes in the built environment may reduce physical signs
of disorder and thereby reduce enticing signals to motivated offenders.
An economic model would argue that changes in the built environment
may shift the equilibrium point at which the supply of criminal opportunities meets the demand for crime by motivated offenders. Truly motivated offenders will still commit crimes, but their average effort will
produce less of a payoff. They will have to work harder to make the same
buck, and the overall demand for crime may fall as a result.
These models provide plausible mechanisms for explaining how crime
is influenced by built environments. So far these ideas have had only limited influence on crime prevention policy. A growing body of evidence,
however, shows that changing aspects of the built environment can reduce crime.
Community Design and Crime
345
II. Zoning and Street Design
The idea of drafting statutes to change the built environment to reduce
crime is not new. King Edward I of England, for example, mandated in
the Statute of Winchester (1285) that highways leading from “one market of town to another” be widened, woods and brush be cleared within
200 feet, and parks have walls constructed so that robbers would not
have cover for their offending (Anderson et al. 2013).
A. Zoning
The built environment may affect crime through land use planning.
Zoning changes that make criminal activity more difficult can be linked
to prevention mechanisms articulated in CPTED, situational crime prevention, and economic opportunity theories. Nonresidential forms of land
use may generate physical decay, which can be linked to broken windows theory.
1. Cross-Sectional Studies. A number of cross-sectional studies examine how land use varies with crime and other observable features of places.
Taylor et al. (1995) found that Baltimore and Philadelphia blocks with
more commercial uses had higher rates of vandalism, litter, abandoned
property, and dilapidated buildings. Harrell and Roman (1994) found that
higher rates of robbery occurred in Washington, DC, census tracts with
higher percentages of lots zoned for commercial uses. Stucky and Ottensmann (2009) found that violent crime rates were higher in small geographic street grids in Indianapolis when areas were zoned for highdensity residential units (eight or more per acre) and commercial land
uses. High-density residential units, when concentrated in poor areas,
were associated with higher violent crime rates. The opposite was true
for commercial land use, suggesting that violent crime rates in areas of
higher poverty are not particularly affected by commercial land uses.
Thus, there appear to be some aspects of zoning that affect crime.
Browning et al. (2010) found that violent crime was associated with the
density of commercial and residential buildings per census tract (n p 184)
in Columbus, Ohio, controlling for poverty, residential stability, and
other demographic factors. Homicide and assault followed a slightly curvilinear pattern. There was a slight increase in homicides and assaults in
less densely settled areas, but they diminished after that, suggesting that
more densely settled areas may be safer. The effects were relatively small:
a 10 percent increase in the density of land translated into a 2–3 percent
346
John MacDonald
decrease in homicide and aggravated assault rates. By contrast, robberies
tended to increase in blocks with greater density. These findings, they suggest, imply that robberies are more likely to be strategic and to occur
around commercial areas. Homicides and assaults often arise from disputes
that draw the attention of neighbors. Commercial areas also generate additional street traffic and population density during business hours.
A few studies have compared different land use designs of neighborhoods. Greenberg, Rohe, and Williams (1982) examined three pairs of
neighborhoods in Atlanta that differed substantially in reported crime (high
vs. low) but were contiguous and had similar income and racial composition
characteristics (black middle income, black lower income, white middle
income). Higher-crime neighborhoods (measured by crimes per block)
were more likely to have commercial and other nonresidential uses, a
lower percentage of blocks zoned solely for single-family homes, and
large roadway arteries. It is important to note that these comparisons
were only descriptive and did not involve statistical tests of differences.11
Greenberg and Rohe (1984) surveyed just over 500 residents in these
neighborhoods to measure
