Reducing Crime Through Environmental Design: Evidence from a Randomized Experiment of Street Lighting in New York City

As in almost every city in the United States, the risk of crime victimization in New York City differs between the economically disadvantaged and the more affluent.  Addressing this disparity while maintaining New York City’s crime reductions is a key policy challenge. One promising approach is to invest in making the physical environment less conducive to criminal activity.  It has long been thought that street lighting can impact crime and yet little rigorous evidence exists to support this contention -- until now.

In partnership with the Mayor’s Office of Criminal Justice, the New York City Police Department and the New York City Housing Authority, Crime Lab designed a randomized controlled trial involving nearly 40 public housing developments, all of which had elevated levels of crime, and half of which received new lights and half did not.

The lights study found that the developments that received new lights experienced crime rates that were significantly lower than would have been the case without the new lights. Among other findings, the study concluded that increased levels of lighting led to a 36% reduction in "index crimes" — a subset of serious felony crimes that includes murder, robbery and aggravated assault, as well as certain property crimes — that took place outdoors at night in developments that received new lighting, with an overall 4% percent reduction in index crimes.

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