The effect of citywide improvement in street lighting on the use of public space by community residents.

Theories from environmental criminology suggest that place-based interventions can enhance public safety by increasing public space use, improving natural surveillance, and fostering a sense of guardianship. However, few studies employ detailed data on how people utilize public spaces, negating the ability to test mechanisms purported in environmental criminology. This study uses high-resolution foot traffic data connected to cell phones to examine the impact of Philadelphia's installation of 34,374 upgraded LED streetlights on public space utilization in general and in areas that experience significant reductions in crime subsequent to streetlight upgrades. Lighting upgrades slightly increase nighttime mobility, particularly near discretionary locations, with increases that are particularly prominent among residents visiting businesses within their own neighborhoods. Importantly, increased foot traffic is not concentrated in areas that experienced measurable crime reductions following lighting improvements, a finding which is potentially consistent with the idea that behavioral responses may be driven less by actual safety changes in and more by the visible presence of better lighting itself. The findings demonstrate how mobility data can advance empirical tests of environmental criminology.