Project Summary A controlled trial evaluation of the Philly Streetlight Improvement Project Firearm violence, especially within urban neighborhoods of concentrated disadvantage, is a persistent public health problem in the US. There is a growing body of experimental evidence that place-based interventions that improve the built environment can help curb gun violence. Experimental and quasi-experimental evaluations show that street lighting, a common municipal investment, is effective at reducing violence8-10 Yet, the effectiveness of a permanent citywide improvement in street lighting has never been scientifically tested. Understanding whether improvements in street lighting can have an impact on gun violence at scale is of critical value to policymakers who must decide how to allocate scarce resources among many different crime control strategies. Building on our prior experimental and quasi-experimental studies, we propose to conduct the first citywide quasi-experimental study of the installation of energy-efficient “smart” street lighting and its potential impact on shootings, gun assault, robberies with firearms, and weapons offenses. This will be the first multi-year study of the benefits upgrading street lighting on gun violence across multiple neighborhoods and can inform other cities that are looking for place-based investments that can help curb the epidemic levels of gun violence impacting neighborhoods of concentrated disadvantage in US cities. In the first phase of the project we will study changes in gun violence outcomes in the 12 months before and after the installation of new street lights on 300 blocks compared to 900 blocks that have yet to have lights installed and have comparable pre-existing monthly levels of gun violence. In the second phase of the project we will estimate the citywide impact by estimating a difference-in-differences regression for approximately 40,000 blocks in the city that have new street lights installed between years 2023-2025. Key covariates will also be accounted in the difference-in-differences regression models as well as adjustments for multiple testing. Critically, our research will also involve qualitative assessments of the implementation of street lights and a partnership with the Urban Affairs Coalition to assess whether street lighting upgrades help to facilitate equity and feelings of safety to economically disadvantaged neighborhoods.

Project Narrative To the best of our knowledge, there have been no prior controlled trials of the effects of a citywide installation of energy-efficient street lighting on gun violence outcomes. Leveraging the staggered rollout of an ambitious public infrastructure project which will upgrade of all 130,000 street lights in Philadelphia, we will study the at-scale effects on investments in street lighting on gun violence outcomes. The proposed project’s findings will contribute to the local and national effort to understand ways to improve the built environment of communities and reduce the burden of gun violence.