Can enhanced street lighting improve public safety at scale?

Street crimes are thought to be influenced by changes in ambient lighting; yet, most studies have focused on small-scale interventions in limited areas. It remains unclear whether enhanced lighting can improve safety on a larger, jurisdiction-wide scale. This study examined the first 10 months of Philadelphia's citywide rollout of enhanced street lighting. Between August 2023 and May 2024, 34,374 streetlights were upgraded across 13,275 street segments, converting roughly one third of the city's street segments to new LED (light-emitting diode) fixtures that provide clearer and more even lighting. We assessed the impact of these upgrades on total crimes, violent crimes, property crimes, and nuisance crimes. Our findings reveal a 15% decline in outdoor nighttime street crimes and a 21% reduction in outdoor nighttime gun violence following the streetlight upgrades. The streetlight upgrades may have contributed to 5% of the citywide decline in Philadelphia gun violence during the study period. Qualitative data also suggest that resident perceptions of safety and neighborhood vitality improved after new streetlights were installed. 

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