A one-way system known as a "concrete collar" round a Kent town is to be switched to two-way traffic in time for Monday morning's rush hour.
The two-way system will open after six months of roadworks
Medway Council said disruption was inevitable during the traffic switchover in Chatham, which takes place after six months of roadworks.
The one-way system will be closed from midnight on Saturday to allow new signs and traffic lights to be put in place.
The new system will be opened to vehicles during Sunday afternoon.
"This decision has been made after talks with police and other organisations," said Mark Bradbury, head of Chatham development at Medway Council.
"A degree of disruption - possibly major disruption - is inevitable until people get used to the new layout.
"But it is a little pain for a lot of gain."
Brook Street and Best Street will change to two-way traffic, with stopping or unloading banned. The Sir John Hawkins flyover will be closed except to buses, taxis and cycles.
Council staff will be patrolling junctions to guide drivers round the new layout.
The £2.5m two-way system is part of a 20-year programme to improve town and river sites in Strood, Chatham, Rochester and Gillingham.
Mr Bradbury said it would open up Chatham's waterfront and make the town centre an easier and more enjoyable place to visit.
Phase two of the road project, which takes place next year, includes demolition of the flyover, new car parks and a new bus station.