Whether lighting deters thieves or just helps them see what they’re doing has been a hot topic of discussion. When you stop your car on a quiet residential street at night, do you park under a traffic light, thinking that the bright light will deter a thief from entering your vehicle? Intuitively it seems like the right thing to do, after all it would be easier to go unnoticed when stealing a car in the dark. Conventional wisdom says thieves like to work this way.

You’re wrong. New research shows that turning off street lights reduces the number of vehicle-related crimes.

Study. The research, published in the Journal of Quantitive Criminology, challenges conventional assumption by suggesting that car theft rates are lower on dark streets than on better-lit streets. The team from the London School of Hygiene and Tropical Medicine and UCL analyzed police data on crimes recorded in the UK and data on changes in public lighting from April 2004 to September 2013.

They found that robberies were halved on streets that adopted “partial night lighting” (PNL), where the lights were turned off between 00:00 and 5:00 a.m.

Less theft overall. Interestingly, this coincided with a significant 1.5-fold increase in vehicular crime on nearby streets where the lighting was left on all night, suggesting that some criminals decided to move to better-lit nearby streets. However, less crime was “displaced” to these nearby locations, meaning an overall reduction in crime.

Why? While the purpose of the study was not to find the causes of the observed changes, Dr. Phil Edwards said, “When the lights go out after midnight, criminals, a Flashlight, likely arouse suspicion among residents and risk being tracked, outweighing the benefits.”

Also, when the lights go out after midnight, the streets will likely be almost dark, meaning potential criminals may have trouble seeing if there are any unsecured valuables in the vehicles, so they prefer to move elsewhere. But the report does not mention the impact the lack of lighting has on the elderly and the most vulnerable in society: fear of crime and their reluctance to leave their homes at night.

applicable measures. One of the reasons for this study is that many local authorities in European countries have implemented partial night lighting on quiet urban residential roads and rural roads that have little use after midnight to save energy costs and reduce carbon emissions. And such security questions have always been raised.

The results show that energy-efficient street lighting retrofits do not increase crime on the streets studied.

An argument gone wrong. Specifically, for decades, researchers have studied the relationship between street lighting conditions and crime. Despite years of mixed findings, police, governments and citizens still believe that improving street lighting can reduce crime. Eight studies conducted between 1974 and 1998 came to mixed conclusions about whether improving street lighting reduces crime.

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