A £17.5 million scheme which will tackle congestion on the M4 and help access thousands of new homes in Swindon is starting next month.

Highways England has teamed up with Swindon Borough Council, Swindon and Wiltshire Local Enterprise Partnership and developers Persimmon and Redrow to deliver extra lanes at M4 Junction 15 and improve road routes from the motorway.

The year-long project starts on August 10 and aims to improve journey times and reliability for motorists by tackling congestion at the busy M4 junction and on the A419, particularly at peak times in the area.

The upgrade is being jointly funded by Swindon Borough Council (£4.8m), SWLEP (£3m) and Persimmon and Redrow (£4.35m).

The upgrade follows the start of two major  council schemes – the Wichelstowe underpass project further south near M4 junction 16, and improvement work at the White Hart junction, a vital link between the A419 and A420.

The M4 junction 15 programme of work will involve:

• Widening of the A419 southbound approach to M4 J15 Commonhead Roundabout from 2 to 3 lanes, with a dedicated left lane for London-bound traffic

• Widening of the A419 northbound exit from M4 J15 to three lanes up to the Highways England compound entrance, and back to two lanes north of the compound exit

• Widening of the A346 to the south of M4 Junction 15 from one to two lanes, and from two to three lanes on the immediate approach to the roundabout

• Widening of the M4 J15 eastbound exit slip road from two to three 

• Lengthening of the three-lane M4 J15 westbound exit slip road 

• Widening of the M4 J15 southern circulatory carriageway from two to four lanes

• Upgrading existing footpaths and installing a new signalised pedestrian crossing over the M4 Junction 15 westbound entry slip road.

Mark Fox, south west head of scheme delivery for Highways England, said: “Our roads are vital for the country and its economic success - they connect businesses and communities and support employment and new homes.

"All of our improvements will ultimately ensure our roads continue to improve journeys and unlock the potential for new jobs and homes.”

During the scheme, embankments will be cleared and remodelled, and the Day House Lane road, although closed to vehicles, will remain open for non-motorised users.

Throughout the project, any work requiring overnight closures and traffic management arrangements will be communicated in advance.

Mr Fox added: “We will make every effort to ensure that the impact on the local community is kept to an absolute minimum, we’ve started with some preparatory work, and as the scheme progresses we will communicate any changes via roadside signage.

“We appreciate that roadworks can be frustrating but we’d like to thank motorists in advance for their patience while this vital improvement scheme takes place.”

Swindon Borough Council’s £4.8m investment will complement more than £72.5m in road improvements at the nearby New Eastern Villages development.

Coun Gary Sumner, Swindon Borough Council’s Cabinet Member for Strategic Infrastructure, Transport and Planning, said: “Anyone who has sat in the tailbacks at Junction 15 of the M4 at peak periods knows just why these improvements are needed.

“I am pleased this vital work is about to start as it will relieve congestion on what is a notoriously busy bottleneck. This is a further of example of the council investing in the Borough’s road network to benefit both local residents and the wider Swindon economy.”

Paddy Bradley, CEO of the Swindon and Wiltshire Local Enterprise Partnership, said: “The scheme represents our continued commitment to local businesses and residents and the works will help ensure the economic growth of Swindon and the wider region is not hindered by traffic congestion and unreliable journey times.

“The collaboration between partners to bring together the necessary funding will lead to the improvement of major routes around Swindon to keep pace with the future development of the New Eastern Villages.”

Highways England’s Growth and Housing Fund has been used to match-fund infrastructure projects to unlock developments around the country.