An experimental 30mph speed restriction on A35 in Dorset is set to be made permanent following the outcome of an air quality trial carried out by Highways England.

It says it’s been investigating effective measures to improve air quality on and alongside the strategic road network for six years and has developed a programme of measures to improve air quality at specific locations around the country, including traffic management and managing speeds to reduce emissions.

The village of Chideock has been identified as an Air Quality Management Area by Dorset Council, the pollution control and monitoring authority, and working closely with the local authority, Highways England initiated a trial speed limit along a section of the A35 at the western end of the village in September 2019.

The 18-month trial – involving the installation of monitoring equipment, patrols by an emissions monitoring vehicle, and temporary 30mph speed restriction – is complete and following the collection and analysis of data, results have now been shared with Dorset Council.

Andy Roberts, Highways England Route Manager for the A35, explained, “As part of our ongoing work, we undertook and completed a trial which saw additional diffusion tubes installed and an electric-powered van monitoring real-time pollution before and after the speed limit change. This identified a small reduction in nitrogen dioxide levels following the reduction of the speed limit and as a result of the localised air quality benefit, we propose to make the extended 30mph zone a permanent fixture.”

(Picture – Highways England)