West Sussex Highways will be making some signs clearer on the A24 between Washington and Southwater.
Engineers will be improving traffic and direction signs at specific locations to make them easier to read for motorists.
Teams are replacing some signs and installing new ones.
Vegetation will be cleared, road surfaces improved, road markings upgraded and existing signs cleaned.
Work is set to start on Monday, March 6 and will last for seven weeks.
It will be carried out in three phases:
Phase 1 – Washington to Wiston Business Park (northbound);
Phase 2 – Wiston Business Park to Ashington (southbound);
Phase 3 – Southwater to Buck Barn (southbound).
At certain times during the works one lane will have to be closed to keep traffic and the work force safe.
West Sussex Highways advise motorists to look out for warning signs as lane closures will move for each phase.
Five nights of overnight working are required during phase 2.
No work will take place over weekends.
West Sussex County Council’s Cabinet Member for Highways and Transport, Bob Lanzer, said: “Clear signs and visibility along the A24 will bring about better driver behaviour.
“It will reduce unexpected manoeuvres, such as drivers missing signs and then suddenly trying to exit the A24 at the last minute.
“This work requires a lane closure at certain points, so we ask motorists to bear with us while we get these improvements completed.”
The works cost £184,000.