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04 Mar 2021
Jamie Gibbs Jamie Gibbs

Motorway speed limits cut to curb pollution


Heavy traffic on the motorway

Sections of motorway in England and Wales have lower speed limits in an effort to curb pollution.

Let us know what you think of the speed limit cuts in the comments box below.

In 2019, the transport sector accounted for 34% of the UK’s total carbon emissions, according to GOV.UK. It’s also the UK’s largest producer of emissions. 

The UK has set itself an ambitious target to become a zero-carbon country by 2050. 

But we won't reach that target unless the government takes greater action. That's according to Energy Institute's Energy Barometer report

To that end, Highways England cut the speed limit on certain sections of motorway to 60 mph. And Wales has expanded its network of 50 mph zones. 

But one in four (26%) people think it’s not worth the inconvenience*.


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How does speed impact carbon emissions?

Speeding up requires power, which burns more fuel. Slowing down uses the brakes, which give off harmful brake-dust particles.

With constant speeding up and slowing down on the motorway, you can see how pollution can build up fast.

Cutting the speed limit to 60 mph rather than 70 mph means less acceleration. This means less fuel consumption, and fewer emissions.

Highways England estimates that a 60 mph speed limit on the motorway could cut emissions by as much as 17%.


Where are the 50 mph zones in Wales?

At the end of March 2021, a new average 50 mph zone will appear on the M4 between J24 Coldra and J28 Tredegar Park.

But this isn't a new initiative for Wales. In December 2018, five stretches of road in Wales had their speed limits cut to 50 mph due to emissions:

  • A494 at Deeside

  • A483 near Wrexham

  • M4 between junctions 41 and 42, Port Talbot

  • M4 between junctions 25 and 26, Newport

  • A470 between Upper Boat and Pontypridd.

Emissions in those areas fell enough that the new speed limits became permanent in June 2019.

Transport Minister Ken Skates said of the change:

“I would hope most motorists would agree that helping to save people from illness or even death is more important than saving a minute or so on their journey.”


Where are the revised speed limits in England?

They're on four stretches of motorway around Birmingham, Manchester and Sheffield:

  • M6 junctions 6 to 7 Witton

  • M1 junctions 34 to 33 Rotherham 

  • M602 junctions 1 to 3 Eccles

  • M5 junctions 1 to 2 Oldbury


Highways England has identified another four areas with poor air quality. But these roads already have speed restrictions in place for other reasons:

  • M4 Harlington junctions 2 to 4 – due to roadworks

  • A1 Blaydon Gateshead – due to roadworks

  • M621 junctions 6 to 7 Leeds – original permanent speed limit is 50 mph

  • M32 junctions 1 to 3 – due to roadworks


The lower speed limits will be in force 24 hours a day during the trial.


Are electric cars exempt from this?

No, the speed limit applies to all vehicles.

Even though electric cars have zero emissions, they still need to stick to the new speed limit.

This is for reasons of safety and practicality. Having one rule for EVs and another for everyone else could cause confusion.

Ivan Le Fevre, Head of Environment at Highways England said:

"Ultimately the air quality challenge will be solved 'at the tailpipe' by vehicle manufacturers and changes in vehicle use.

"Until this happens we will continue our extensive programme of pioneering research and solutions."

READ MORE: Electric cars: the complete guide


What do Brits think of the trial?

We asked 2,000 people whether they thought cutting motorway speed limits was a good idea.

Over a third (34%) agreed that it was. But almost a quarter (24%) disagreed.

More than half (53%) said that drivers wouldn't obey these lower limits anyway. And over a quarter (28%) believe the government should do more elsewhere to lower emissions.

But nearly a third (32%) think that cutting motorway speeds is a good way to help the environment.


How can I reduce emissions when I drive?

Reducing your speed is one way to keep your emissions down.

But if you want to do more, here are some tips:

  • Inflate your tyres to the correct pressure

  • Remove excess weight in the car

  • Switch off your engine when you’re stuck in traffic 

  • Maintain a steady speed to avoid acceleration or braking

  • Service your car regularly


You might think these tips sound an awful lot like how to improve your fuel economy. That’s because they are.

If you improve your fuel economy, your car burns less fuel. Fewer emissions are pumped into the air, and you save yourself some cash by not topping up as often. It’s win-win.

Find out how much your journeys are costing you with our fuel cost calculator.


*Figures taken from omnibus research carried out by OnePoll on behalf of This was a nationally-representative poll of 2,000 UK adults. The research was conducted between 11 and 15 November 2020.


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