Home Before the Lights Come On: The Effect of LED Lighting on Movement

• In Event: Place-Based Public Investments and Crime: Evidence on Lighting, Mobility, and Community Infrastructure

Abstract

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, testing these mechanisms has been limited by a lack of detailed data on how people utilize public spaces. This study examines Philadelphia’s installation of 34,374 upgraded LED streetlights to assess whether improved lighting affects foot traffic using high-resolution mobility data to points of interest, following on from previous findings that this intervention reduced crime by 5-15% in areas that received lighting upgrades. Results in this study show that lighting upgrades slightly increase nighttime activities, particularly near discretionary locations like restaurants and nightlife as well as on weekends. Overall, we observe an increase in foot traffic of 4-14% at the median number of lights installed per 1,000-meter-wide hexagon (approximately 41 lights). These increases are particularly prominent among residents visiting businesses within their own Census tracts (an increase of 26%, compared to a non-resident increase of 5%). Visitor gains appear to be generated by already-active individuals becoming more active or extending visits (intensive margin) rather than new individuals becoming active (extensive margin). We also observe a potential shift from heavily trafficked locations to lesser-volume points of interest, in line with a higher willingness to venture to non-necessary or otherwise avoidable places. Importantly, increased foot traffic is not concentrated in areas that experienced measurable crime reductions following lighting improvements, suggesting that behavioral responses may be driven less by actual safety changes in and more by the visible presence of better lighting itself. Finally, we provide an exploration and validation exercise of the data products that inform mobility and foot traffic studies, identifying that algorithmic normalization procedures and outlier smoothing techniques may flatten out any potentially detectable effects, a concern with the new generation of mobility data products. The findings demonstrate how mobility data can advance empirical tests of environmental criminology.

Author

• Maya Moritz, University of Pennsylvania
  Presenting Author