Currently reading: Motorway sections given 60mph limit in effort to reduce NOx levels
Highways England reveals ambitious plan to accelerate emissions reduction in most polluted areas
3 mins read
20 July 2021

A 60mph speed limit is being imposed on some sections of motorway in England as part of a wide-reaching emissions reduction programme overseen by Highways England (HE). 

In a new report, the infrastructure management body said that it's "committed to improving air quality in and around the Strategic Road Network (SRN)" and supports the government's ambition to reduce levels of nitrogen dioxide (NO2) in the atmosphere.

HE has partnered with the Department for Transport (DfT) and the government's Joint Air Quality Unit (JAQU) to monitor and, if necessary, modify 101 sections of the national road network where levels of NO2 exceed legal limits.

Of the 101 sections of road highlighted by the study, 30 were found to have above-average levels of NO2, of which eight now have a lower speed limit in place, in an effort to reduce the emissions generated by traffic.

The affected sections of road include part of the M1 motorway near Rotherham in Yorkshire, junctions 1-2 of the M5 in the West Midlands and a stretch of the M6 at Witton in Birmingham. 

HE is also investigating other means of mitigating emissions around busy roads. On the A3 through Guildford in Surrey, for example, where NOx levels are at double the legal limit, it's working with the local council to determine the feasibility of a 9.3m-tall 'vertical air quality barrier'. It says the urban nature of this stretch of road makes such a device complex to install. 

Meanwhile, a scheme in certain areas will have buses fitted with an exhaust filtration device that's claimed to lower their NOx output. Traffic-flow improvement schemes are also being investigated as a means of reducing idling time and congestion. 

In some areas, HE has determined that it couldn't feasibly deploy emissions-reducing measures that would reduce NOx in a timeframe quicker than that already forecasted. This includes a section of the A34, which runs from Oxford to Southampton, where the body will "continue to investigate whether there are new or emerging ideas and/or technologies that could be considered". 

Diversions of heavy goods vehicles in peak times on certain roads, are also being planned, with the requisite road signs currently being designed and installed for part of the A500 from Nantwich to Stoke-on-Trent. 

HE forecasts that emissions levels will come down naturally as electric vehicles become more popular. It's supporting the switch to EVs with a scheme to incentivise electric van adoption in Bristol, Derby and Nottingham and has promised to accelerate EV charging infrastructure development from 2020-2025.

As part of a plan to make Britain's roads carbon-neutral by 2050, HE will install more efficient LED lighting across the network, make its own vehicle fleet fully electric and plant an additional three million trees by 2030.

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In the following decade, it will ensure that all construction and maintenance activities on the road network are net-zero, and by 2050 it plans for all vehicles using the English road network to be net-zero. 


What would a 60mph motorway speed limit do for NOx emissions?

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Peter Cavellini 20 July 2021

Darn it!, spell check, not reading it, Lane blocker, the ones who think there teaching the person behind that you have every right to sit in the outside lane at 69 mph! .

Stockholm Calling 20 July 2021

A lane jogger Peter? No wonder the traffic was being held up!

Peter Cavellini 20 July 2021

Was on the M-way today actually,and most of the Traffic was doing about 60mph, the usual culprits zoomed by, Van man in a hurry, Lane jogger holding up a car behind presumably because he was driving too close, or just because it was quite hot today (26C) , not a lot of Traffic, so emissions wouldn't be that high,the nearer the Cities though?, well, I can see the point of setting speed limits at 60mph.