Reducing Gang Crime.

The Los Angeles Police Department employed a deceptively simple tactic, traffic barriers, to block automobile access to streets as a way of reducing gang violence. The National Institute of Justice (NIJ)-sponsored evaluation of Operation Cul-de-Sac (OCDS), as the program was called, examined whether the tactic could reduce gang crime.

In its 2 years of operation, 1990-1991, OCDS appeared to reduce violent crime. Homicides and street assaults fell significantly in both years and rose after the program ended. Property crime decreased substantially during the first year, but it also declined in the comparison area that had no OCDS operating, indicating that other factors besides the traffic barriers caused the reduction. Moreover, in the second year of the program, property crime rose, suggesting that the street closures affected only violent crime. Lastly, crime was not displaced to other areas. This may have occurred because the areas of potential displacement are the turf of rival gangs.

Agencies can use traffic barriers as part of an approach to maximize neighborhood residents' defensible space by increasing their span of control. Zones configured with the barriers heighten the visibility of suspect activities and can prove effective when combined with "natural guardians," people who serve as informal sources of surveillance and social control. To order a copy of this report, "Designing Out" Gang Homicides and Street Assaults, NCJ 173398, contact NIJ's National Criminal Justice Reference Service at 800-851-3420, or access the home page at http://www.ncjrs.org.