Traffic flows along one of the main routes into Bognor Regis will be halved by major roadworks.
The thousands of motorists who use a dual-carriageway section of the A29 Shripney Road will find it down to a single lane in both directions from tomorrow (Monday, January 9).
A 30mph speed limit will also be imposed. The disruption is expected to last for six months.
It is being caused by the construction by Barratt Homes of a new roundabout to connect the A29 to the new northern relief road which bypasses central Bognor Regis.
Cllr Brian Knight, Bersted Parish Council’s chairman, said: “The roundabout has got to be built. It is going to be a major scheme and it is going to cause problems because we are going to lose one side of the A29.
“But I am optimistic that is being handled as well as possible and that it will go ahead without too many major problems.
“The work is being carried out by the same people who built the relief road roundabout at the Felpham end.
“The same man who controlled the traffic lights there will be controlling the traffic lights on the A29.
“He did a very good job at Felpham and, if he does the same here, then I’m sure any difficulties will be kept to a minimum.”
The roundabout is being built between the Rowan Way roundabout of the A29 and Shripney Lane.
It will mark the western end of the relief road’s eastern section.
Cllr Knight said he was pleased with the co-operation the parish council had received from Barratt as well as from fellow builder Berkeley Homes.
“It has been exceptional. They have talked to us and kept us informed about what is going on.
“This means that when Barratt told us right turns in and out of Shripney Lane where it meets the A29 were being banned during the roundabout works, we were able to ask them to keep open Shripney Lane, which has been closed, during that time.
“That will enable residents to still get to Bognor through the Rowan Way junction,” he said.
The Observer reported last month that Barratt and West Sussex County Council were locked in an impasse about payments to maintain the new road.
But a spokeswoman for Barratt said building the roundabout showed the company’s commitment to the road.
“The new roundabout will form the connection between the existing road and the new relief road that will help to relieve the current congestion problems in the area,” she said.