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Cutting traffic cuts vandalism, burglary and violence, research shows

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A photograph of a line of cars in traffic jam next to a bus lane with trees and houses on the street behind.

Lowering traffic on urban streets can cut vandalism, burglary and violence, according to a significant new study by Leeds researchers.

The work, led by Professor Jose Pina-Sánchez and Dr Toby Davies from the University of Leeds School of Law, shows that levels of street crime go up if motor traffic increases – and there is a corresponding drop if traffic levels fall.

The researchers analysed data from tens of thousands of households across England, Scotland and Wales to examine how changes in traffic levels relate to how safe people feel in their communities. 

Professor Pina-Sánchez said: “We found that when heavy motor traffic arrives in a neighbourhood, residents' perceptions of street crime go up, and the two appear to be causally linked, not just coincidentally correlated.”

Traffic erodes community ties – neighbours talk less, trust each other less, look out for each other less

Professor Jose Pina-Sánchez, University of Leeds School of Law

Perceptions of crime give a more representative picture of a neighbourhood, capturing people’s real experiences rather than relying on police figures, which are known to be inconsistent and under-report the true extent of crime, he added.

By using robust longitudinal data analysis methods, the researchers are confident the link between heavy traffic and street crime is causal, not just coincidental. The mechanisms by which heavy traffic leads to increased street crime are less clear, but their findings point to two working theories.

Professor Pina-Sánchez added: “Our findings suggest two potential explanations. Most importantly, traffic erodes community ties – neighbours talk less, trust each other less, look out for each other less, and feel less ownership of shared spaces. This is known as collective efficacy, and its absence is one of the strongest predictors of street crime.”

Head and shoulders shot of Professor Jose Professor Jose Pina-Sánchez
Professor Jose Pina-Sánchez, University of Leeds School of Law. Image: University of Leeds

Another explanation relates to physical conditions in the neighbourhood - often called the “Broken Windows Theory”. Visible signs of disorder – litter, graffiti, antisocial behaviour – caused by heavier traffic will in turn lead to higher perceptions of crime.

The research was published in peer-reviewed academic journal Kriminologie on Monday, June 29 and uses data from the ONS’s nationwide “Understanding Society” survey. 

It is the first study to examine the link between street traffic and crime on a national level. Previous research has often relied on “before-and-after” evaluations of specific Low Traffic Neighbourhoods (LTNs) in London.

The survey focuses on people’s perceptions of crime rather than police-recorded statistics.

A head and shoulders images of Dr Toby Davies
Dr Toby Davies, University of Leeds School of Law. Image: University of Leeds

Dr Davies added: “Police data tends to underestimate crime, and that underestimation varies across areas.

“By tracking individuals’ perceptions of how safe their neighbourhoods are over time, we are asking the same people how they see crime in their areas at different points in time, which means we avoid some of the biases inherent in official crime data. 

“When people feel a difference in crime, and the only thing that has changed is the level of traffic, we can be confident that this is the cause.”

The Understanding Society study sees interviewers speak to residents about traffic and crime in their neighbourhood, and also records the interviewers’ own opinion on whether the nearest road was subject to heavy traffic. The two measures are collected separately, ruling out any possible interviewer bias.

The Leeds findings align with existing, less comprehensive, studies on LTNs in London. That research found that restricting through-traffic led to roughly a 10% reduction in recorded crime, and by using more a more comprehensive national research design Professor Pina-Sánchez and Dr Davies have confirmed this causal link.  

Professor Pina-Sánchez added: “Low traffic neighbourhoods and 20mph zones are already justified on road safety, health and environmental grounds. Our findings add crime reduction to that list. The societal cost of road traffic is routinely estimated by economists — but crime costs have rarely been included, partly for lack of evidence. We hope this study helps fill that gap.”

When people feel a difference in crime, and the only thing that has changed is the level of traffic, we can be confident that this is the cause.

Dr Toby Davies, University of Leeds School of Law

The researchers are now calling for residential development design guidelines to consider levels of road traffic and their impact on crime. The UK's Secured by Design guidance has historically focused on reducing "permeability": limiting access points to make it harder for criminals to enter and escape. However, if reducing pedestrian connectivity pushes people into cars, and more cars make streets less safe, then the researchers warn those design choices may be feeding crime.

“Crime prevention needs to think more holistically about transport and urban design,” Dr Davies added.

“We need to be sure that, in preventing crime from one perspective, we do not promote car dependency, which has negative consequences of its own.  Implementing designs that discourage traffic while still keeping neighbourhoods safe are likely to be one of the most effective and cost-efficient tools at our disposal to make streets safer.”

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