PHILADELPHIA -- 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 non-greened sites. Additionally, researchers 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. Full results of the study were published online this week in Injury Prevention.

"Vacant lot greening changes the physical environment of a neighborhood from one that may promote crime and fear to one that may reduce crime and make people feel safer," said lead author Eugenia C. Garvin, MD, a resident in the Department of Emergency Medicine at the Perelman School of Medicine. "Our theory is that transforming vacant lots from a space overgrown with vegetation and filled with trash to a clean and green space may make it difficult for people to hide illegal guns and conduct other illegal activities such as drug use in or near the space. Additionally, green space may encourage community cohesion."

The study is the first to use a randomized controlled trial design — the gold standard in scientific research — to examine the effects of vacant lot greening. Researchers randomly selected two clusters of vacant lots – one cluster which was later greened, and one control cluster which was not. The team worked with members of the Pennsylvania Horticultural Society who performed greening of select vacant lots by removing debris, planting grass and trees, building fences, and performing regular maintenance every two weeks.

"Philadelphia LandCare has helped transform thousands of vacant lots in key neighborhoods across the city," said Bob Grossmann, director of the Pennsylvania Horticultural Society's vacant land program. "We know that these improvements help neighborhoods and residents in a number of ways, but studies like the one led by Dr. Garvin help us to determine very specifically how we're impacting the city so we can continue to drive change where it's needed most and in the way that will have the most positive effects."

Twenty one residents living near both sites were interviewed before and after the greening. Survey results show that residents living near the greened vacant lots felt significantly safer at the three-month follow-up visit compared to those near the control site. Additionally, the research team analyzed police reported crime data from three months before and three months after the greening. Total crime, as well as assaults with and without a gun, was less after the greening.

Results from two other portions of the interview are still being analyzed: an in-depth qualitative interview about the impact of the physical environment on health, and a walking interview around the neighborhood, in which residents' heart rates were monitored. The goal of the walking interview was to explore a link between the environment and heart rate, a physiologic marker for stress. Data from the interviews will be published at a later time.

Click here to view the full release.