A-road upgrade costing £300m to begin this week
Work to dual part of a major A-road, costing up to £300m, is expected to begin this week.
National Highways is creating two additional lanes and two new junctions on a 5.5-mile (8.9 km) stretch of the A47 in Norfolk, between North Tuddenham and Easton.
The scheme was delayed by 20 months due to legal challenges lodged by environmental campaigners.
National Highways says it hopes to have the stretch of road open by spring 2027 - and drivers should expect some delays.
"Once this scheme is built it will be much safer to travel," said Matt Stafford, a regional delivery director at National Highways.
"There will be much better visibility, the junctions will be better and there will be fewer collisions.
"It's been a long time coming , we're here to build the scheme and we're [getting] on with it."
The A47 runs between Lowestoft and Leicester, and passes Norwich, King's Lynn, Wisbech and Peterborough.
It is considered one of Norfolk's most dangerous roads and it has a number of pinch points due to increasing levels of traffic.
National Highways is planning to upgrade two other parts of the A47 in Norfolk, costing up to £100m each.
They include dualling the stretch between Blofield and North Burlingham, and improving the junction at Thickthorn, south-west of Norwich, which links the A47 to the A11.
All three projects were thrown into doubt when a former Green Party councillor attempted to have them blocked.
Dr Andrew Boswell claimed the Department for Transport's development consent orders, approved in 2022, failed in each case to assess the significance of the cumulative greenhouse gas emissions, as required by law.
He lost his case at the High Court and then had a challenge dismissed at the Court of Appeal.
In May, the UK's Supreme Court turned down Mr Boswell's application for a legal challenge to be heard there.
National Highways said delays to the three schemes had caused costs to soar due to the impact of inflation.
Overnight road closures were expected to begin early next week.
Follow Norfolk news on BBC Sounds, Facebook, Instagram and X.