Motorists are being urged to plan their journeys as a bout of resurfacing work begins on the A690;
The road maintenance, due to last for six days, starts today on the southbound carriageway of the A690 between the county border with Sunderland and Rainton Gate.
During the work a contraflow system will operate on the northbound carriageway of that section of the road. Five central reservation crossover points will also be closed.
Diversion routes for residents in West Rainton and Rainton Gate will be in force.
John Reed, head of technical services at Durham County Council, said: "This work is part of our essential maintenance programme which is aimed at keeping the county's roads in good condition.
"We appreciate that this is a busy commuter route in and out of Durham and we would ask road users to be patient and allow extra time for their journeys while we carry out this work."