Scots road chiefs say a multi-million-pound project to ease congestion on one of the busiest stretches of road in the country will be delivered “on time and on budget”.

The A80 linking Glasgow, Stirling and the north east carries vital business and commuter traffic.

The gradual increase in the amount of traffic has added pressure to the dual carriageway.

The new five-mile section of motorway, to run parallel with the A80, is expected to reduce traffic at the Mollinsburn and Stepps junctions by 45,000 vehicles a day and drastically reduce congestion in Moodiesburn, Chryston and Muirhead.

It is also claimed the £320million scheme will cut journey times on the main route from the Highlands and the north east to Glasgow and the south by 30% to 40% during peak periods.

Government agency Transport Scotland is upgrading the A80 Glasgow to Stirling trunk road between Stepps and Haggs, bringing the stretch to motorway standard.

It will tie-in with the Auchenkilns Junction, which was created when a roundabout was removed, and which opened in 2005 mid-way between Stepps and Haggs.

Michelle Rennie, head of construction on the M80 project, said: “Drivers using the A80 between Stepps and Haggs will be familiar with the sheer scale of the works being undertaken to upgrade this major Scottish arterial road.

“We have been careful to require our contractor to maintain the present dual carriageway during peak times given the importance of this road to communities and businesses in the Central Belt and further afield.”

Road bosses say the project, which is currently running to schedule, is due to be completed by autumn, next year.

In May work began to lay the surface on a new section of the motorway.

This eight kilometre section between Stepps and Mollinsburn includes eight bridges, 11 culverts to carry six local roads and footways over the road.

At the time, Transport Minister Stewart Stevenson, said: “The start of the Tarmac going down on the new section between Mollinsburn and Stepps is a major milestone in this project.

“The peak time congestion faced during construction is the same congestion that makes this upgrade vital to the economy and communities.”

The upgrade area passes close to hundreds of homes and passes directly over a string of disused mines which have had to be made safe before the work on the motorway can begin.

And while all this work is taking place, the road has remained open, with few delays reported.

Ms Rennie added: “Now that the schools are back, it is inevitable that the road will be busier but it is important to remember that this is the same congestion, often through populated areas, which this project is designed to alleviate.

“The road continues to carry some 76,000 vehicles a day and we recognise that the nature of the works has led to some additional disruption.

“We do all we can to warn motorists of traffic management and we continue to thank them for their continued patience.

“When completed next year the £320m M80 Stepps to Haggs project will bring improved journey times, reliability and safety for people using this busy route.”