Air quality - our programme of activity

What we're doing to improve air quality along the strategic road network.

Air quality

We’re implementing a programme of measures around the country to improve air quality at specific locations on the strategic road network. These locations are called Pollution Climate Mapping (PCM) links.

These measures include:

  • traffic management
  • managing speeds to reduce emissions
  • working to accelerate the uptake of zero emission vans
  • air quality barriers

Traffic management

Traffic management includes activities such as diversions, speed control, signal timing/location, signage/dynamic signage, junction reconfiguration or changes to road alignment. All these can help manage local air quality issues.

To improve air quality at non-compliant locations on the strategic road network, we’ve been assessing the potential impact of traffic management measures at these sites. In some cases we believe traffic management could potentially improve the air quality, so we’re now undertaking further work to develop plans for these sites. Options being considered include:

  • junction improvements, closing junctions or particularly on and off slip roads
  • changing the timing of traffic lights and Installing new traffic lights on roundabouts
  • exploring routing HGVs
  • introducing dynamic signs that advises drivers according to the traffic volumes
  • reviewing the speed limits and installing addition speed cameras
  • working with local authorities to improve bus and cycle lane improvements to reduce local traffic

Managing speeds to reduce emissions

We have a legal duty to tackle air quality around our network and are committed to meeting the targets in the Government's Nitrogen Dioxide (NO2) plan.

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

Until this happens we’ll continue our extensive programme of pioneering research and solutions.  As part of this, we’re introducing 60 mph speed limits on short sections of our network, each up to 4.5 miles, where action needs to be taken. This will be on a trial basis, and the temporary reduced speed limits will stay in place until the shift to cleaner vehicles means we can remove the restrictions and maintain clean air.

We expect there will be a reduction in NO2 when traffic speed is reduced from 70 to 60mph in these locations, based on our extensive traffic and air quality modelling, air quality monitoring and wider research programme.

The speed limits will be clearly displayed through roadside signs and variable messages signs.

Learn more about our air quality speed limit trials.

Experience from Wales

We have been following closely the work to reduce speed limits to 50mph in Wales. Emissions of nitrogen dioxide have reduced at all five locations on the motorway and trunk road network where 50 mph speed limits were introduced, monitored data shows. While air quality remains a complicated issue and further evidence is needed to prove the speed limits have had an impact on NO2 limits, the initial findings show positive improvement in air quality after the first full year of the speed limits being introduced.

Working to accelerate the uptake of zero emission vans

The use of vans on our network has grown significantly over the last few years and is forecast to grow further. These vehicles produce a disproportionate amount of pollutants – 33% of the oxide of nitrogen (NOX) emissions from 15% of road traffic. Importantly zero emission alternatives are available and absolutely viable for many.

We’re working with local authorities in Leeds, Coventry, Kent, Nottingham and Sheffield to implement try-before-you-buy schemes in an effort to accelerate the uptake of electric vans. Our research with the Energy Saving Trust showed that providing vans users with the opportunity to try a vehicle for free for up to two months will give many confidence to make the switch and buy their own electric vans.

Air quality barriers

We’re currently exploring the opportunities for physical barriers to improve air quality at specific locations on our road network.

These provide a physical barrier to divert pollution away from homes and sensitive locations. Our pollution monitoring in Holland close to an existing tall sound barrier, installed to reduce noise, has produced interesting results. These findings suggest this type of barriers could help improve air quality, and we are actively undertaking technical development work to assess how and where these types of barriers could bring benefits at hotspots on our road network.

Interview: Talking electric vans with two industry experts

We're super-charging a green incentive scheme with a multi-million-pound investment that allows businesses to try electric vehicles for free before they buy.

Chris Plumb, air quality specialist at Highways England, talks with Tom Callow, an electric vehicles industry expert, about the scheme and the future of electric vehicles.

Zero emissions van trial
Zero emissions van trial

Get in touch

If you have something you’d like to discuss with us, please get in touch by emailing

Air quality

Improving air quality on the Strategic Road Network