Some roads in Chatham have been closed as the one-way ring road is turned into a two-way system.
The two-way system will open after six months of roadworks
Drivers have been advised to use the A2 or Medway Tunnel and shoppers have been offered free park-and-ride services from Strood and Chatham Maritime.
The road system changeover is expected to be completed by Sunday afternoon in time for the Monday morning rush hour.
Closures began at midnight on Saturday to allow new signs and traffic signals to be put in place.
Medway Council said disruption was inevitable during the traffic switchover in Chatham, which was taking place after six months of roadworks.
Brook Street and Best Street have been changed to two-way traffic, with stopping or unloading banned. The Sir John Hawkins flyover has been closed except to buses, taxis and cycles.
Council staff said they would 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.
Phase two of the road project, which takes place next year, includes demolition of the flyover, new car parks and a new bus station.