Citywide cluster randomized trial to restore blighted vacant land and its effects on violence, crime, and fear

TLDR

Vacant and blighted urban land, covering about 15 % of U.S. city areas, poses widespread environmental risks that undermine both safety perceptions and physical safety. The study aimed to evaluate how standardized vacant‑land restoration interventions influence violence, crime, and residents’ fear and safety perceptions. The trial employed a mixed‑methods design, randomly assigning 541 vacant lots to treatment or control, and collecting police data and surveying 445 residents over 38 months.

Abstract

Vacant and blighted urban land is a widespread and potentially risky environmental condition encountered by millions of people on a daily basis. About 15% of the land in US cities is deemed vacant or abandoned, an area roughly the size of Switzerland. In a citywide cluster randomized controlled trial, we investigated the effects of standardized, reproducible interventions that restore vacant land on the commission of violence, crime, and the perceptions of fear and safety. Quantitative and ethnographic analyses were included in a mixed-methods approach to more fully test and explicate our findings. A total of 541 randomly sampled vacant lots were randomly assigned into treatment and control study arms; outcomes from police and 445 randomly sampled participants were analyzed over a 38-month study period. Participants living near treated vacant lots reported significantly reduced perceptions of crime (-36.8%, P < 0.05), vandalism (-39.3%, P < 0.05), and safety concerns when going outside their homes (-57.8%, P < 0.05), as well as significantly increased use of outside spaces for relaxing and socializing (75.7%, P < 0.01). Significant reductions in crime overall (-13.3%, P < 0.01), gun violence (-29.1%, P < 0.001), burglary (-21.9%, P < 0.001), and nuisances (-30.3%, P < 0.05) were also found after the treatment of vacant lots in neighborhoods below the poverty line. Blighted and vacant urban land affects people's perceptions of safety, and their actual, physical safety. Restoration of this land can be an effective and scalable infrastructure intervention for gun violence, crime, and fear in urban neighborhoods.