Image: Jack Fifield, via Flickr
Low-traffic neighbourhoods (LTNs) reduce traffic and air pollution without displacing the problem to nearby streets, according to a new study.
The study by researchers at Imperial College London looked at three LTNs in London, to identify their impact on both air pollution and traffic within the LTN zones and in the surrounding area.
LTNs aim to reduce through traffic in residential areas, usually by the use of barriers which prevent cars from using certain streets, while leaving them open to pedestrians and cyclists.
Many LTNs were put in place during 2020, to prevent an increase in vehicle traffic as people avoided public transport during the Covid pandemic. However, they also provoked opposition, with critics claiming that LTNs increased traffic and pollution in surrounding areas.
The researchers studied three LTNs in Islington, one of London’s most densely populated boroughs, which were put in place during 2020.
The team compared pollution and traffic levels at monitoring stations inside the zones, on streets surrounding the zones, and at control sites further away, using data gathered by Islington Borough Council.
The LTNs – in St Peter’s, Canonbury and Clerkenwell – were put in place between July and September 2020. The team analysed data gathered from July 2019 to February 2021.
Researchers found that concentrations of nitrogen dioxide fell by 5.7% within the LTNs and by just under 9% on their boundaries, compared to the control sites.
They also found that traffic dropped by over half inside the LTNs and by 13% at the boundaries, compared to the controls.
Dr Audrey de Nazelle, from Imperial’s Centre for Environmental Policy, said: “This research effectively disproves the argument that low-traffic zones will necessarily cause an increase in traffic and air pollution in neighbouring streets.
“In the three areas we looked at, they reduced both traffic volumes and, significantly, air pollution both inside and on the edges of the zone.
“Alongside the other benefits of LTNs that have been shown in previous research – such as improvements in safety and an increase in walking and cycling – this makes a very strong argument in their favour.”
The report has said that the data was collected between July 2019 and Feb 2021, as the Covid Lockdown only officially ended in November 2020 and was replaced by local restrictions there were still a large number of people working form home and not travelling.
Before the report can give a definite answer to the question of traffic being displaced and if this has increased the amount of pollution to the surrounding areas they would need to gather more data now that we are more or less fully back to normal working conditions with the associated increase in communting.
Stephen Hughes
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