A study from the Perelman School of Medicine at the University of Pennsylvania has found that green spaces are linked to reduced crime rates
A research team has found that distressed neighborhoods where vacant lots have been converted into small parks and community green spaces are associated with reduced crime when compared to neighborhoods with unimproved vacant lots. The study was conducted by a group from the University of Pennsylvania's Perelman School of Medicine, using Philadelphia data compiled over the last decade. In some sections of the city, residents of neighborhoods with improved vacant lots also reported "significantly less stress and more exercise," suggesting that the improvements had an effect on residents' perceptions of safety outdoors.
Philadelphia has a major program to take advantage of vacant lots within the city to add 500 acres of additional neighborhood parks, gardens, and other green space by the end of 2015. In addition, according to a press release issued by the Perelman School, the Pennsylvania Horticultural Society has had a program to green abandoned vacant lots in the city since 1999. Nearly 4,500 vacant lots totaling over 7.8 million square feet were greened from 1999 to 2008. The Horticultural Society's inventory of work formed the basis for the new study:
This program involved removing trash and debris, grading the land, planting grass and trees to create a park-like setting, and installing low wooden post-and-rail fences around each lot to show that it was cared for and to deter illegal dumping. Several times a year, PHS returned to each greened lot to perform basic maintenance, such as mowing the grass, tending trees, or repairing fences.
[Penn's Dr. Charles C.] Branas and his team analyzed the impact of this program for a decade, from 1999 to 2008, using a statistical design that considered various health and safety outcomes and numerous other factors occurring on and around vacant lots, before and after they were treated, as compared to vacant lots that were not greened over the same time period.
A control group of unimproved vacant lots was selected with a methodology designed to ensure fair comparability to the greened lots. The study, which was published earlier this month in the American Journal of Epidemiology, correlated the lots with data from the Philadelphia Police Department and the Southeastern Pennsylvania Household Health Survey.