Government has approved Highways England’s (HE) proposal to improve a 32 mile stretch of the M4 motorway between junction 3 (Hayes) and junction 12 (Theale) by making it an ‘all lane running’ smart motorway.

The smart motorway will use the technology to improve journeys by monitoring traffic flow and setting speed limits accordingly to keep traffic moving. The upgrade will involve converting the hard shoulder permanently to a traffic lane to create extra capacity. Information about road conditions and speed limits will be displayed to drivers on electronic road signs.

The government’s decision accepts the view of HE and the Examining Authority panel that the all lane running solution is safer than the current situation and would best achieve increased road capacity through the most cost effective design rather than an alternative solution of dynamic hard shoulder running.

However, government also states that HE will have to complete further monitoring of Air Quality as the scheme progresses. The decision acknowledges that the current air quality techniques have a degree of uncertainty and that mitigation might be required if the results are worse than modelled.

Construction is due to start in March 2017. More information on the decision can be found by clicking here.