Low-traffic neighbourhoods seemingly can prompt residents to drive less, with a study showing people in one London borough cut their driving by nearly a mile a day on average after LTNs were introduced.
While the research covers only four LTNs created in 2020, it is potentially significant because it contradicts the objection from opponents of the schemes that they make people drive further on less direct routes.
It comes at a crucial time for the future of the schemes, with the Department for Transport under Mark Harper appearing unsympathetic towards them after negative coverage in some newspapers.
Filters on smaller residential streets that allow bike and pedestrian access but prevent through-traffic by motor vehicles have been used in the UK for decades, but became controversial after a number were installed at the start of the Covid pandemic, branded as LTNs.
Proponents say they make smaller roads quieter and more tempting for walking and cycling, and also make it less convenient to drive, thus prompting a shift in behaviour by some people for briefer trips. Opponents say they simply lengthen and displace motor vehicle journeys.
The new study, published in the journal Transport Findings, used mileage data logged as part of MOT tests from thousands of vehicles in Lambeth, south London. It showed an average decline in driving of 0.7km (0.4 miles) a day for every vehicle inside LTNs, two years after they were installed, compared with a rise of 0.6km for streets 200 metres or more outside their boundaries, for a net 1.3km (0.8 miles) reduction, or 6.4%.
The authors of the study, led by Dr Anna Goodman, an epidemiologist from the London School of Hygiene and Tropical Medicine, said the increase in average driving outside the LTNs appeared to be due to Covid and other external factors, rather than people skirting the LTNs.
People living the closest to the LTNs, within 200 metres of their edges, who would be expected to be most affected by such changes to driving trips, recorded an increase in their average driving levels, but by less than those further away.
The study, also involving academics from the University of Westminster and Imperial College London, linked the mileage data logged in annual MOT tests – mandatory for all cars or vans three years old or more – with information about residents’ parking permits to estimate average distances driven each year per vehicle.
This was initially calculated for 2018 to 2020, to take into account the position before the LTNs were installed, and then between 2021 and 2023. The data covered just over 8,500 cars and vans for the first period, and more than 10,000 for the second.
Adding to the expectation that the net reduction in driving was caused by the LTNs is the fact that the data from 2018 to 2020 showed no difference in trends between the areas subsequently covered by the zones and those outside.
Similarly, the decrease in mileage was seen in households with the same vehicle registered in 2020 and 2023, indicating the change was not caused by people who drive more frequently simply moving out but by a change in behaviour.
The areas within and outside the LTNs had largely similar demographic and socioeconomic profiles, while the changes in driving were seen in more deprived and more affluent areas, the study found.
The overall 1.3km-a-day reduction covers all journeys, including longer-distance ones, meaning the effect on reducing local car and van trips could be even greater.
Goodman said: “To achieve an estimated 6% relative decrease in total annual driving is really impressive. Moreover, for shorter and more local trips it is plausible that the relative decrease in residents’ driving is even greater than 6%.
“This matters because, while reducing driving of any type is good news in terms of carbon emissions, reducing driving within cities brings large additional health benefits in terms of air pollution, noise and road safety.”
