Plans to spend up to £1.4bn improving a major junction on the A1 have been unveiled.
The project will overhaul the Black Cat roundabout near Bedford which links the A1 with the A421 and the A428.
The scheme includes a new 10 mile (16km) dual carriageway between the junction and the Caxton Gibbet roundabout near Cambourne.
The existing A428 will become a local road serving communities between St Neots and Caxton Gibbet.
The proposed route follows a public consultation in 2017 in which more than 4,000 people and organisations took part.
Highways England said the improvements would save drivers about 10 minutes on an average commute between the Black Cat and Caxton Gibbet junctions.
Project lead Lee Galloway said: "This major new dual carriageway between St Neots and Cambridge and upgrade for the Black Cat junction will mean quicker and safer journeys for people and will also boost the economy and unlock housing.
"The improvements will complement our £1.5bn A14 upgrade and form part of a wider transformation of road links between Cambridge, Milton Keynes and Oxford."
Laura MacKenzie, infrastructure campaigner at Friends of the Earth, said: "New, bigger roads create more traffic and repeatedly fail to deliver the congestion benefits promised. Road building tends to mean more air pollution and climate-changing emissions and often major harm to our natural environment too.
"The huge sums of public money allocated to road building schemes like this could be much better spent elsewhere - specifically on improving public transport and investing in walking and cycling infrastructure."