‘No evidence that 60mph limit cuts pollution’

Call to end trials of lower speeds on motorways as proof of reduced emissions has failed to emerge

‘They’ve got to either come up with facts or concede that the scheme was not designed for its purpose’

SPEED limits that force motorists to drive at less than 60mph should end, campaigners have said, after it emerged the trials have lasted twice as long as originally proposed without producing evidence that they reduce emissions.

Drivers on stretches of the M1, the M6, the M5 and the M602, have been limited to the top speed to determine whether lower speed limits would benefit the environment.

But the reduced speed limits, which were only due to last between 12 and 15 months, have been operating for more than two years, despite a lack of evidence that they are effective.

And some campaigners have suggested that congestion caused by the lower limit actually increases pollution.

Motoring groups and a former roads minister are among those calling on National Highways to produce data from the trials or end them. Modelling had suggested the lower limit would significantly reduce nitrous dioxide concentrations in the affected zones and that this would help areas near Rotherham in South Yorkshire, Witton in Birmingham, Eccles in Greater Manchester and Oldbury in the West Midlands meet pollution targets sooner than expected. But it has been claimed that the modelling did not consider particle pollution produced by braking.

The policy also penalises electric vehicles that produce no exhaust emissions and newer, less polluting cars.

More than two years since the trials began, no data has been published to show air quality has improved. But the trials have caused frustration for drivers who have also endured delays due to years of smart motorway upgrades.

Sir John Hayes, a former roads minister, said National Highways should show that the trial was working or reinstate the national speed limit.

He added: “Air pollution is a real concern but the relationship between speed of traffic and pollution is complex. When you have congested traffic, emissions grow. It’s hard to legitimise the argument that the difference between 60 and 70 is significant in terms of emissions, but I’d be happy to look at the facts. They’ve got to either come up with the facts or concede that the scheme was not designed for its purpose.”

Iain Stewart, the Conservative chairman of the Transport Select Committee, said: “I’ve got a general concern about having things that evolve by a creeping change without it being evidencebased. I would certainly want to quiz them on what data that they’ve established thus far has shown and whether that gives a justification for these speed restrictions to be made permanent.

Claire Armstrong, of Safe Speed, a campaign group, said the scheme may have made pollution worse.

She said: “If you slow traffic, you risk creating congestion and the more congestion the more pollution.”

A spokesman for National Highways said: “As part of this process we are taking a series of actions, such as lowering speed limits on some roads. Robust findings informed our decision and these 60mph limits will remain in place until the air quality [on them] has met legal limits and will continue to do so when the measure is removed. Given the complexity and amount of data needed, this requires appropriate time to complete all the stages of the analysis process.

“National Highways is looking to produce initial reports on the performance of the real-world 60mph speed limits in spring 2023.”