Low traffic neighbourhoods get academic approval: green light for a tool to create sustainable cities

Independent academic experts have found that controversial low traffic neighbourhoods (LTNs) in outer London deliver massive health benefits that far outweigh the investment costs. Hopefully this should settle the issue for good.

Just eight months ago, the writing appeared to be on the wall for local government schemes that limited motorists’ freedom — perhaps done by an angry spray-can wielding opponent. The Conservatives had scored a lone and unexpected parliamentary by election victory in Uxbridge and South Ruislip in west London.

The victor had claimed it was a sign of opposition to London Mayor Sadiq Khan’s ultra low emissions zone (Ulez) that imposed penalties on high-emitting vehicles and which had just been extended to the local borough, Hillingdon, Labour leader Sir Keir Starmer appeared to agree, saying that the local party was doing “something very wrong”.

At the same time there was increased and often violent opposition to LTNs, schemes where motor vehicle traffic in residential streets is greatly reduced by erecting bollards and restrictions enforced by cameras. Opponents vandalised the cameras and tried to destroy or neutralise the bollards. The right-leaning press picked up on the protests as another “woke” agenda conflict.

Two-point turn?

But since then, the feeling of a turning point has dissipated, and advocates are confident that both interventions are becoming accepted in communities. Khan’s office came out with data showing that harmful pollution emissions had reduced by 26 per cent within the expanded Ulez area — compared with what they would have been without the Ulez coming into force.

The feeling has been bolstered by a six year study of the impacts of “active travel infrastructure” in three of the capital’s outer boroughs: Enfield, Kingston and Waltham Forest.

The work led by Professor Rachel Aldred of Westminster university and carried out with academics at Cambridge university and another London college found that the 50 or so schemes had generated more than £1 billion worth of health benefits for a cost of £100 million — a 10-fold return on investment.

It calculated an estimated average benefit of just over £4,800 per adult aged 20–80 due to increased physical activity. They compared that to an estimated cost per person of around £112 for higher-quality LTNs or £27–£35 for lower-cost versions.

One reason was that two years after the schemes’ implementation, there was a doubling in the amount of time spent on active travel — walking or cycling — and a 30 per cent decline in car use.

It is the not the first study to identify positive impacts. In 2022 a team at Imperial College London found that LTNs in the brough of Islington reduced traffic and air pollution without displacing the problem to nearby streets. The researchers found that concentrations of nitrogen dioxide fell by 5.7 per cent within the LTNs and by just under 9 per cent on their boundaries, compared to the “control” i.e., non-LTN sites, some distance away.

Another study identified potential benefits in terms of safety. Researchers found that introducing LTNs, this time in the inner London borough of Southwark, led to a decrease traffic speeds and

volumes. Again, traffic volumes on boundary streets did not increase in most neighbourhoods.

Back to Ulez and one study late last year found that it had significantly improved air quality, benefitting Londoners’ physical and mental health. Among other benefits researchers at the University of Bath found an improvement in general health levels, a reduction in both hospital admissions for respiratory issues and in prescription costs for those ailments.

Beyond the election

But academic research goes only so far, especially in a likely election year. Media outlets critical of these sustainability measures have already launched attacks on both Ulez and LTNs. The Conservatives have already sought to make it a woke issue, attacking the “sinister” misuse of the 15-minute city — the idea that everything a person needs should be within a quarter of an hour's walk or cycle from any point in their neighbourhood.

But if academic researchers have identified benefits, it is likely that people living in or near the areas will have experienced those improvements first-hand. Criticisms of the projects, such as the idea that they increase air pollution on nearby roads, can be debunked. It will not be a smooth journey but LTNs and schemes such as Ulez are here to stay.