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Wednesday, December 11, 2019

Explained: Do better-lit streets really make a city safer?

Arvind Kejriwal has announced his government will install 2 lakh streetlights across Delhi. What does research say about the link between crime and street illumination?

Written by Yashee , Edited by Explained Desk | New Delhi | Updated: September 24, 2019 9:17:07 am
Explained: Do better-lit streets really make a city safer? Delhi Chief Minister Arvind Kejriwal has said his government will install over 2 lakh streetlights across Delhi. (Express File Photo)

Delhi Chief Minister Arvind Kejriwal has said his government will install over 2 lakh streetlights across Delhi, in a bid to fight crime and make the city safer for women. This is not the first time Kejriwal has linked the absence of lighting to crime — in 2016, the Delhi government had roped in SafetiPin, a mobile application and online platform that does safety audits of cities, to map “dark spots” in Delhi that could be more dangerous for women due to poor illumination.

On the face of it, it stands to reason that better-lit streets would be safer and less prone to crime. There aren’t enough detailed studies on the subject available publicly for India to draw a definite conclusion, but multiple research papers in the West have found that more streetlights do not necessarily mean an across-the-board reduction in crime.

The findings of the research are nuanced: While some studies say there is no direct link between crime and street illumination, others have found that while better lighting did curb certain kinds of petty crimes and property crimes such as theft and robbery. The presence of bright lights, however, had little effect on violent crimes such as murder.

Yet other studies say better-lit streets could actually increase crime.

However, most studies seem to agree that more street lights contribute to people “feeling” safer, and having a better opinion of a neighbourhood.

A 2008 study by College of Policing, UK (, says: “Improved street lighting had a positive effect in reducing crimes such as burglary and theft. It did not, however, reduce the incidence of violent crimes. Perhaps surprisingly, the positive effects of improved street lighting are felt in the daytime as well as at night.”

The study explains the improvements seen during daytime as a result of residents feeling better about their neighbourhood, and hence being more vigilant in guarding it themselves.

“The broken windows hypothesis suggests that physical dilapidation in an area gives the impression that ‘nobody cares’ and thus no one will intervene against crime and disorder. Improving the environment displays ‘civic pride’ that demonstrates how much local people care about their locality. The installation of enhanced street lighting can make a location more welcoming which may in turn increase informal social control. The community see that others are concerned about their area (by installing better street lighting) and begin to take a pride in the area themselves,” the study says.

Another explanation for this is that installing streetlights tells miscreants local authorities care about an area, which can act as a deterrent.

The findings were largely similar in a 1991 research carried out by a team from the University of Southampton for The Home Office Crime Prevention Unit of the UK (, which was cited by several later studies, and was among the more exhaustive such researches carried out in that period.

This study found that better street lighting had little effect on crime in an area. “The dominant overall conclusion … was of no significant change,” the study says.

However, the researchers did report that better lighting was “warmly welcomed by the public, and that it provided a measure of reassurance to some people — particularly women — who were fearful in their use of public space.”

In 2008, Brandon Welsh and David Farrington, working for The Campbell Collaboration, assessed “available research evidence on the effects of improved street lighting on crime in public space”.

They found that “the studies indicate improved street lighting significantly reduces crime, is more effective in reducing crime in the United Kingdom than in the United States, and that nighttime crimes do not decrease more than daytime crimes”.

However, their study showed marked variations: For the USA, “in 4 evaluations improved street lighting was considered to be effective in reducing crime (Atlanta, Milwaukee, Fort Worth, and – for violence – Kansas City). In the other 4 evaluations, the improved street lighting was considered to be ineffective (Portland, Harrisburg, New Orleans, and Indianapolis)”.

Also, the study said: “In the experimental area, property crime decreased but violent crime did not.”

In the UK, improved street lighting was generally found effective, but “improved lighting was followed by a significant reduction in property crime but not in violent crime”.

A research published in 2015 in the UK, by researchers from the London School of Hygiene and Tropical Medicine and University College London, concluded: “There was no evidence from the overall estimates for an association between the aggregate count of crime and switch off or part-night lighting. There was weak evidence for a reduction in the aggregate count of crime and dimming [of lights] and white light.”

However, an April 2019 study carried out by Crime Lab in association with the Mayor’s Office of Criminal Justice, the New York City Police Department and the New York City Housing Authority did find a drop in crimes with better city lighting.

This research says: “Among other findings, the study concluded that increased levels of lighting led to a 36% reduction in “index crimes” — a subset of serious felony crimes that includes murder, robbery and aggravated assault, as well as certain property crimes — that took place outdoors at night in developments that received new lighting, with an overall 4% per cent reduction in index crimes.”

On the other hand, Arizona state university’s Center for Problem-Oriented Policing has a paper adapted from a 1999 research by Professor Ken Pease, a crime prevention expert, which talks of how improved lighting can increase crime.

Some of the points are: Increased visibility of potential victims allows better assessment of their vulnerability and the value of what they carry. Offenders might more easily be able to see if parked cars contain valuable items; Increased visibility allows better judgment of the proximity of “capable guardians” who might intervene in crime; Better lighting might facilitate activities like drug dealing and prostitution.

The Washington Post reported that “a 1997 National Institute of Justice report to Congress concluded that we can have very little confidence that improved lighting prevents crime, particularly since we do not know if offenders use lighting to their advantage.”

Thus, if the researches are anything to go by, while the new streetlights that the Kejriwal government brings to Delhi might make Delhiites feel better about their city and possibly, their government, they may not necessarily make the city safer.

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