Four junctions along a nine mile section of the A27 between Lewes and Polegate will be improved and a section of the Polegate bypass will be upgraded to dual carriageway.
Publication of project details follows public consultation on the scheme last year.
Highways England project manager Tom Beasley said: “People’s input has helped to shape our plans and we’ve made some key changes to our proposals to make sure they deliver the biggest benefit. In particular we’ve prioritised improvements at Polegate including the Gainsborough Lane junction, over the Selmeston bypass option and introduced a new enhanced option for upgrading the Wilmington junction – all as a result of people’s input.”
Proposals to upgrade Selmeston junction have been withdrawn after no options could be found that would deliver a worthwhile benefit without having an unacceptable impact on the South Downs national park.