A £2.4 million scheme to ease congestion on the M5 for commuters travelling from Thornbury into the city has been given the green light.

The Department for Transport has awarded South Gloucestershire Council £1.68 million from its Pinch Points Fund to create additional lanes at the roundabouts of both junction 16 Thornbury and 17 Cribbs Causeway.

The A38 will be widened as part of the improvement work at the approach to junction 16 and a dedicated left-turn slip onto the M5 northbound route will be provided.

The remaining £700,000 will be provided by the local authority.

The work will aim to improve traffic flow at the bottle-neck junctions as well as create safe and easy access to new and existing housing and employment hubs in the North Fringe. Cllr Brian Allinson, conservative lead member for planning and transport, welcomed the news.

“I’m delighted that we have secured this funding because removing traffic bottle necks is how we can keep South Gloucestershire moving and help get people to and from work, which will help to power our local economy,” he said.

The plans were put forward by South Gloucestershire Council to offset the impact of the new 5,750-home development at Cribbs Causeway and Patchway on current and thousands of new commuters on that stretch of the motorway.

Council officers bid last summer for a share of the government's £165 million Pinch Points fund to secure the extra £1.7 million needed to carry out the work.

In their application, they highlighted the many traffic problems already plaguing commuters, explaining these would only worsen in the coming years.

“The council’s forecasts suggest these problems will be exacerbated by the Cribbs Patchway New Neighbourhood (CPNN) development," they wrote to the Department for Transport. "Hence, the proposed improvements are designed to improve the efficiency of the operation of these junctions, thereby helping to mitigate the impact of the CPNN development and improving access to the site.”

The creation of new Enterprise Area in Filton was also a major factor in putting more adequate traffic flow measures in place.

The upgrade will complement improvements the Highways Agency is planning to make to the motorway slip roads at the junctions.

Construction will start in 2014 and is expected to be completed by spring 2015.