New Evidence Supports Earlier Studies Suggesting Greening Vacant Lots May Reduce Violent Crime

By Eugenia C. Garvin, Carolyn C. Cannuscio, and Charles C. Branas

Philadelphia, PA (August 7, 2012) – Greening vacant lots may make neighborhood residents feel safer and may be associated with reductions in certain gun crimes, according to a new study from the Perelman School of Medicine at the University of Pennsylvania. Results show that residents living near greened vacant lots feel safer than those near sites without trees, grass, and other vegetation. Researchers also noted that incidents of police-reported crimes may be reduced after greening. The results expand upon previous studies and are the next step in helping researchers understand the full impact of vacant lot greening on crime, safety, and health.

Background:

Vacant lots are often overgrown with unwanted vegetation and filled with trash, making them attractive places to hide illegal guns, conduct illegal activities such as drug sales and prostitution, and engage in violent crime. There is some evidence that greening vacant lots is associated with reductions in violent crime.

Methods:

We performed a randomised controlled trial of vacant lot greening to test the impact of this intervention on police reported crime and residents’ perceptions of safety and disorder. Greening consisted of cleaning the lots, planting grass and trees, and building a wooden fence around the perimeter. We randomly allocated two vacant lot clusters to the greening intervention or to the control status (no intervention). Administrative data were used to determine crime rates, and local resident interviews at baseline (n=29) and at follow-up (n=21) were used to assess perceptions of safety and disorder.

Results:

Unadjusted difference-in-differences estimates showed a non-significant decrease in the number of total crimes and gun assaults around greened vacant lots compared with control. People around the intervention vacant lots reported feeling significantly safer after greening compared with those living around control vacant lots (p<0.01).

Conclusions:

In this study, greening was associated with reductions in certain gun crimes and improvements in residents’ perceptions of safety. A larger randomised controlled trial is needed to further investigate the link between vacant lot greening and violence reduction.

Related Resources:
Greening vacant lots to reduce violent crime: a randomised controlled trial, Injury Prevention, August 7, 2012
News Release: Penn Study Finds with Vacant Lots Greened, Residents Feel Safer
Greening Vacant Urban Space may Affect Health and Safety