Air quality - our programme of activity

These locations are called Pollution Climate Mapping (PCM) links.

The measures we are implementing 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 support the delivery of Government’s national air quality plan, ensuring compliance with legal air quality thresholds is achieved as quickly as possible.

The transition to cleaner low emission vehicles will support the ongoing improvements in air quality around the country.

In the meantime we will continue to explore options and take action through our programme of air quality research and interventions. As part of this approach, we are trialling 60mph speed limits on short sections of our road network where action needs to be taken to improve air quality.

We expect to see a reduction in nitrogen dioxide (NO₂₎ when traffic speed is reduced from the national speed limit on motorways (70mph) to 60mph in these locations. This is based on our extensive traffic and air quality modelling and monitoring and wider research programme.

These 60mph limits will remain in place until the monitoring shows that air quality in these locations has met legal limits and that it will continue to stay below these limits when the speed restriction from 70 to 60 mph is removed.

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 (NO_X) 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.

Get in touch

If you have something you’d like to discuss with us, please get in touch by emailing airquality@nationalhighways.co.uk