What Does Research Reveal About Street Access and Crime?

Researchers have argued that closing neighborhood streets and alleys can prevent crime because there is a relationship between street access and crime rates. The details of the argument are as follows:

1. Offenders find targets in familiar territory. They gain knowledge about vulnerable areas and potential opportunities through their contacts with other offenders and through their daily routines, such as hanging out with friends, traveling to work, and going to the movies. This means that frequently traveled streets are more vulnerable to crime.
2. Offenders are quick to recognize a closely knit neighborhood and the presence of people who might notice them. From litter and other signs of neglect, they can judge whether they are likely to be challenged if they deal drugs or solicit for prostitution.
3. Burglars avoid cul-de-sacs and prefer corner sites where neighbors are less likely to see them. Offenders look for heavily traveled streets and locations near major highways, where there are many potential victims and where they can easily escape.
4. Reducing through-traffic by closing streets or alleys means that
   • criminal outsiders are less likely to become familiar with the area;
   • residents learn who does not belong in the neighborhood, which helps them to more effectively keep watch on the streets near their homes;
   • residents committing crime in their own neighborhood cannot so easily blame outsiders and thus deflect suspicion from themselves;
   • burglars cannot so easily gain access to properties, especially from alleys behind houses;
   • escape routes for robbers are blocked off ; and
   • drive-by shootings are prevented because cars cannot easily enter a street, or because they have to backtrack to escape, exposing them to retaliation from those shot at.

Research findings are generally consistent with this theory:

• Areas with street layouts that permit easy access experience more crime than areas with restricted access and complicated street patterns.1
• A study in Vancouver, British Columbia, found that the more entrances to a street, the more crime on that street.2 Most research supports the idea that burglars avoid houses in cul-de-sacs, unless these abut wooded areas or wasteland affording access from the rear.
• A study of 86 Norfolk, Va., neighborhoods found that those with high burglary rates had a larger number of access points from arterial roads.3
• An early study comparing adjacent high- and low-crime neighborhoods found that the low-crime areas did not have major thoroughfares.4
• Reconstruction of a major highway led to the closing of all cross streets in Pompano Beach, Fla., at the highway’s right-of-way. An unexpected side effect was a dramatic reduction in drug dealing, robbery, assault, and other crime in the adjacent neighborhoods during reconstruction. Side streets were reopened after the work was done, but Pompano Beach made traffic modifications and adjusted police patrols to control access to neighborhoods.5

What About Displacement?

The rationale for closing streets and alleys in a particular neighborhood is that outsiders commit much of the crime there, either going there specifically to do so or doing so when passing through. But research shows that criminals typically offend quite close to home, so before closing streets, you should check arrest records to make sure that most of the active criminals in the neighborhood are not residents. Otherwise, you cannot justify the closings. If you find that a high proportion of those arrested are indeed outsiders, you then have another worry to deal with: What if the closures do not stop these criminals, but simply displace them elsewhere in your jurisdiction? What have you gained?

In fact, displacement can be advantageous if it stops the neighborhood from reaching a “tipping point,”6 when minor crimes build up to produce a much more serious problem (the familiar “broken windows” process). If you prevent the neighborhood from reaching this tipping point, then the savings to the city as a whole will be much greater than the costs of displacement to other neighborhoods. But try telling that to the residents of those other neighborhoods! Fortunately, you won’t need to, because research generally shows that displacement is by no means inevitable. Most research shows that if it occurs at all, the crimes displaced are far fewer in number than those prevented.7 This is because some neighborhoods are so attractive to criminals and so full of criminal opportunities that they actually foster crime. It is wrong to think that criminals commit only a certain restricted number of crimes in a specific time period, and stop once they reach those limits. On the contrary, criminals will commit as many crimes as they have the time and energy for, if the crimes are easy to commit, low risk, and profitable. When these conditions change and the rewards of crime decline, or the risks and effort necessary increase, criminals will lower their expectations—as we all must do when opportunities for gain are reduced. This means that street closures do not inevitably result in displacement, and that they can reduce the overall volume of crime.8