A £1m road improvement scheme at the M4 Junction 32 Coryton Interchange is due to start on September 5.
The works are expected to take 12 weeks and should be completed before Christmas.
The works will see the building of a new dedicated lane for traffic leaving the M4 eastbound and heading north on the A470 trunk road. The Welsh Government has said the move will reduce queuing, improve traffic flows and increase safety on the eastbound off slip road.
In addition the works will include new signs, road markings and lightings.
The Welsh Government, in a statement, said: “This is a busy section of the strategic road network and there is likely to be some disruption to road users whist the works are in progress. Traffic management will be in place to protect the workforce, motorists and control of traffic and every effort will be made to minimise inconvenience to road users, local businesses and residents.
“Lane restrictions and unavoidable slip road closures will be undertaken overnight. Drivers will be provided with advanced notice which will also be available via Traffic Wales, the Welsh Government’s traffic information service.
“We would like to thank road users for their patience and ask motorists to take these works into consideration when planning their journeys as the Welsh Government continues in its work to improve the Welsh transport infrastructure.”