The project will dual the single-lane carriageway on the A417 between the Brockworth bypass and Cowley roundabout in Gloucestershire.
A new junction at Shab Hill will provide a link from the A417 to the A436 towards Oxford and into Birdlip. Another new junction will be put in near Cowley, replacing the existing Cowley roundabout.
Kier’s team will include Volker, Arup, Tony Gee and RPS to prepare for and construct the 3.4-mile route.
Kier won the contract following a competitive procurement process through National Highways’ regional delivery partnership framework. It completed a budget setting process with National Highways earlier this year.
The project still requires development consent – the Planning Inspectorate is examining the application. On conclusion of the examination in May, the Planning Inspectorate will send its recommendation to the secretary of state for transport, who will be expected to make a final decision in the autumn.
National Highways project director Michael Goddard said: “Kier has an extensive track record working with National Highways and delivering large scale infrastructure projects, so we are confident they will deliver a scheme that meets our landscape-led vision. We will work together to deliver a project that is sympathetic with the special character of the Cotswolds area of outstanding natural beauty and will support economic growth, improve traffic flows at peak times and make the road safer.”
Councillor Mark Hawthorne, leader of Gloucestershire County Council, added: “I’m really pleased we’ve reached this key stage of this vital project. After such a long wait, it really feels like the solution for the ‘missing link’ is much closer to becoming a reality.
“Completion will bring improved safety and air quality along with more reliable journey times leading to huge benefits for our county’s economy as well as creating new habitats and habitat connections for native wildlife.”