The first smart motorway in the UK’s South West region has been completed ahead of time and under budget.

The motorway was officially launched by Roads Minister Robert Goodwill, covers seven miles of motorway around the Almondsbury Interchange, and includes junctions 19-20 on the M4 and junctions 15-17 on the M5.

It will help lower congestion and improve safety and journey times by introducing variable speed limits and opening the hard shoulder during busy traffic periods.

"We’re pleased to see local businesses and commuters already experiencing the benefits of the smart motorway."

Traffic officers in the Regional Control Centre at Avonmouth will set overhead message signs to inform drivers they can use the hard shoulder as an extra lane and at what speed to drive.

Mr Goodwill said: "Every day, more than 140,000 vehicles use this section of motorway which is an essential gateway to the South West. That is why the Government has invested almost £90m to help improve access and traffic flow on this vital route.

"This is the first smart motorway in the region and I’m delighted that road users and businesses will be able to benefit from the improvements earlier than planned."

The smart motorway was completed within the £88.6m budget and completed two months ahead of schedule by working closely with contractor Balfour Beatty.

The project involved installation of 33 new gantries, refurbishing seven existing ones, resurfacing over 14 miles of carriageway, laying over 30 miles of fibre optic cabling and constructing six emergency refuge areas.

Highways Agency senior project manager Paul Unwin said: "The M4 and M5 scheme demonstrates how a smart and efficient solution can deliver improvements that road users need; more capacity and better management of traffic to reduce congestion and make journey times more reliable.

"We’re pleased to see local businesses and commuters already experiencing the benefits of the smart motorway and have received feedback to this effect."