National Highways warned last week that works were due to take place on A27 westbound between A24 near Worthing (east) and A24 near Worthing (west).
A closure is now in place between the Grove Lodge roundabout (Broadwater) and the Offington roundabout.
These are the junctions with the A24 South and the A24 North.
A National Highways notice read: “Road repairs are planned. Expect disruption everyday between 8pm and 6am from 18 April 2024 to 18 May 2024.”
A photo taken on Tuesday (April 23) shows heavy traffic leading up the Offington roundabout.