Brighter streetlights cut nighttime violence, but only for a while, study finds

As days grow shorter and darkness arrives earlier across much of the country, a new study suggests that brighter streetlights may help reduce nighttime violence — at least temporarily.

Researchers found that outdoor nighttime violent crime fell by about 46% in targeted areas of Newark, New Jersey, during the first six months after aging streetlights were replaced with LED fixtures. The reductions were driven largely by declines in aggravated assaults and robberies, the researchers found.

But the effect faded over time. The upgrades did not produce a statistically significant reduction in violent crime over two years, and researchers found no significant overall effect on property crime.

The findings suggest that improved street lighting may help cities reduce violence in targeted areas, but that infrastructure upgrades alone may not be enough to sustain those gains.

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Between 2019 and 2021, Public Service Electric and Gas Company replaced 1,419 streetlight fixtures in Newark as part of an initiative that prioritized areas based on past patterns of violent crime. The effort involved the Rutgers University-Newark Public Safety Collaborative, which helped identify locations for upgrades.

Researchers analyzed crime reports from the Newark Police Division between 2018 and 2023, comparing incidents near upgraded streetlights with those near fixtures that were not replaced. They examined crimes reported within 200 feet of each streetlight, including aggravated assault, robbery, homicide, burglary, theft and vehicle-related offenses.

The study, which was published in the Journal of Quantitative Criminology, used a quasi-experimental research design to estimate the relationship between the upgrades and crime, rather than randomly assigning streetlights for replacement.

The estimated reduction in outdoor nighttime violent crime was about 35% over the first year. By the end of the two-year period, however, the overall estimated reduction before and after the streetlights’ replacement was smaller and not statistically significant.

The researchers also found no statistically significant overall reduction in property crime following the upgrades. While some categories, including burglary and theft from vehicles, declined during certain periods, the results did not show a consistent effect across property crimes as a whole.

Nor did the analysis find significant evidence that crime simply moved into nearby areas after the lights were replaced. Researchers also found no systematic change in indoor nighttime violent crime, which they examined as a comparison.

The findings add to a mixed body of research on whether improved lighting can prevent crime. Some previous studies have found that brighter lighting is associated with reductions in crime, while others have reported less consistent results. A previous review of studies from four countries found an overall reduction in crime of about 14% following street-lighting improvements.

The Newark study suggests that the timing and durability of any effect may be important considerations for cities weighing investments in street lighting.

The researchers offered several possible explanations for why the reductions in violence diminished. People committing crimes may have adapted to the changes, while the underlying conditions that contribute to crime may have remained. The study also noted anecdotal reports of streetlights being intentionally damaged after the lighting upgrade, though the researchers did not measure whether damage affected the results.

The researchers cautioned against treating lighting improvements as a standalone solution, suggesting that cities consider them alongside community engagement and other crime-prevention efforts.

Stateline reporter Amanda Watford can be reached at [email protected].