Work to ease congestion on a busy junction of the M5 near Gloucester will start on 6 September.
The work, at junction 12, will take place every night for 14 weeks.
New dedicated lanes between the the M5 and Gloucester will be added both north and southbound, and traffic lights will be installed.
Changes have already been made to the junction over the past four years in a bid to cope with increased traffic from new housing developments.
Mark Arberry, project manager at the Highways Agency, said: "Peak-time congestion is a real problem for drivers on this busy section of road.
"The work we are doing will increase the capacity of the junction, improve traffic flow and reduce the safety risk of traffic queuing back on to the M5 main carriageway.
"We have planned every section of this project carefully to keep delays to road users to an absolute minimum.
"Throughout the work, there will be no reduction in the number of lanes available to road users during the day, but the junction will be closed between 8pm and 6am with a diversion in place."
Interim measures to help prevent traffic queuing back on to the M5 were implemented at the junction in 2006, which included extending the exit slip roads.
Councillor Stan Waddington, Gloucestershire County Council's cabinet member for environment and transport, said: "People using this busy motorway junction have been telling us for some time that improvements need to be made."