Evaluation of the Philadelphia Smart Street Lighting Initiative

ABSTRACT
Lethal violence, particularly in urban areas, remains a significant and persistent public safety concern in the United States. A growing body of experimental research indicates that place-based interventions aimed at improving physical locations within cities can help reduce violent crime. Among these, improved street lighting—a routine municipal investment—has been shown through experimental and quasi-experimental studies to reduce violence. However, the impact of a permanent, citywide street lighting upgrade has not yet been rigorously evaluated at scale.
Building on our prior work, we propose the first citywide quasi-experimental study of the installation of “smart” street lighting and its potential effects on shootings, serious assaults, armed robberies, and weapons offenses.
In the first phase of the project, we will examine changes in serious violence in the 12 months before and after the installation of new street lights across 300 blocks, compared to 900 similar blocks where lighting upgrades have not yet occurred and which exhibit comparable baseline trends. In the second phase, we will conduct a citywide analysis using a difference-in-differences regression approach, covering approximately 40,000 blocks where new lighting will be installed between 2023 and 2025. These models will include key covariates and adjustments for multiple comparisons.
In addition to the quantitative analysis, the project will include qualitative assessments of the lighting implementation process. We will also collaborate with the Urban Affairs Coalition to gather local perspectives on how lighting upgrades affect neighborhood safety and public use of outdoor space.

Grant Number: 1R01MD019163-01
NIH Institute/Center: NIH
Principal Investigator: Aaron Chalfin