Costain has delivered a “critical piece of south-west infrastructure” with a new stretch of A30 dual carriageway between Chiverton and Carland Cross in Cornwall.

The National Highways scheme opened for traffic on June 24 after the upgrade to this critical South-west highway.

The widening of the nine-mile stretch of road has already significantly reduced congestion and brought improvements to journey reliability for motorists, cutting journey times along the route in time for the school summer holidays.

The project, which at its peak involved a team of more than 650, began in March 2020 and saw Costain, National Highways and supply chain partners operate in challenging conditions, including the COVID-19 pandemic and an unprecedented 14 Met Office-classified storms over the last year.

The scheme has seen the construction of three new bridges, 10 new underpasses and underbridges, and more than 2.6 million cubic metres of earthworks.

Key milestones have included the safe dismantling of the 32-year-old Tolgroggan bridge between Scorrier and Boxheater, and subsequent construction of a replacement, the construction of a new traffic-free bridge at Chiverton, and the removal of the old ‘Chivvy’ roundabout, Cornwall’s worst accident hot-spot.

The scheme has also had a broad socio-economic and environmental impact, improving the lives of those in the local community.

It has benefitted local wildlife, with 33 multi-species crossing points added along the route, 150,000 trees planted, and the creation of an additional 4.5 hectares of new woodland.

Costain also coordinated a fundraising effort for Cornwall Air Ambulance, supported the provision of STEM activities to local students and appointed local apprentices to the scheme.

Rob Taylor, project director, at Costain, said: “This has been a complex and challenging project but from the outset Costain, National Highways and our supply chain partners have worked as an integrated team to find solutions.

“To see traffic flowing freely on the new dual carriageway is incredibly fulfilling, and this scheme will have a positive impact on people’s lives for many years to come.

“It’s a terrific achievement for all involved, with motorists and residents already benefitting from shorter journey times. The scheme will unlock greater mobility and be a catalyst for growth throughout the region, particularly during the school summer holidays.”

Nick Simmonds-Screech, project director at National Highways, added: “The whole team has worked incredibly hard to move the scheme forward and achieve the opening of the new A30 this June, overcoming a number of major challenges along the way, most notably the Cornish weather.”

The project will be formally completed over the coming months, with ancillary, and finishing-up works.

This will include structures work, local authority road refinements, landscaping, planting, and other environmental and ecological work to be completed before the site closes down.