A study shows that low-traffic neighborhoods reduce pollution in the surrounding streets

Low-traffic neighborhoods reduce pollution in the surrounding streets

Credit: Islington Council

New research shows that low-traffic neighborhoods (LTNs) reduce traffic and air pollution without displacing the problem to neighboring streets.

The study, conducted by researchers at Imperial College London, looked at three LTNs in London, to determine their impact on both air and traffic pollution within LTN areas and in the surrounding area.

LTNs aim to limit traffic in residential areas, usually by using barriers that prevent cars from using certain streets, while leaving them open to pedestrians and cyclists.

Several LTNs were put in place during 2020, to prevent an increase in vehicular traffic as people avoided public transport due to fear of infection. However, they have also generated opposition, with critics claiming that LTNs have increased traffic and pollution in surrounding areas.

The researchers studied three LTNs in Islington, one of the most densely populated boroughs in London, that were established during 2020. The team compared pollution levels and traffic at monitoring stations within the districts, on the streets around the districts, and at remote monitoring sites. , using data collected by Islington Borough Council.

LTNs – at St Peter’s, Canonbury and Clerkenwell – were placed between July and September 2020. The team analyzed data collected from July 2019 to February 2021. The research is published in Transport Research Part D.

Pollution drop

Because each of the long-term networks was set up at a different time and not all monitoring sites collected data continuously, averaging the results among the three long-term networks would not provide an accurate overall picture. So the team conducted a more complex statistical analysis to ensure that other factors that might affect traffic volume and air pollution at certain times — such as COVID restrictions in place, school holidays or weather — could be taken into account.

Using this analysis, the researchers found that nitrogen dioxide concentrations decreased by 5.7 percent within the LTNs and by just under nine percent at their borders, compared to the control sites. They also found that traffic fell by more than half within LTNs and by 13 percent at borders, compared to controls.

Dr Audrey de Nazelle, of the Imperials Center for Environmental Policy, said, “This research effectively refutes the argument that low-traffic areas will necessarily lead to increased traffic and air pollution on nearby streets.”

“In the three areas we studied, they reduced the volume of traffic and, significantly, air pollution in and out of the area. Combined with other benefits of LTNs that have been shown in previous research – such as improvements in safety and increased walking and cycling – this makes a strong case for very much to their advantage.”

Co-author, Imperial College London Ph.D. Student Helen Yang added: “This is the first study to use a robust statistical approach to show the effect of LTNs on surrounding areas, and the results are really encouraging. We worked with a relatively small data set and more research is now needed to confirm these findings on a larger scale.”

more information:
Xiuleng Yang et al, Evaluation of the effects of low traffic neighbor (LTN) on NO2 traffic, Transport Research Part D: Transport and the Environment (2022). doi: 10.1016/j.trd.2022.103536

Provided by Imperial College London

the quote(2022, November 25) Study Shows Low-Traffic Neighborhoods Reduce Pollution in Surrounding Streets. Retrieved November 25, 2022 from https://phys.org/news/2022-11-low-traffic-neicturess-pollution- streets. html

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