Overtaking restrictions for lorries are to be tried out on two sections of the A1(M) in County Durham in a bid to improve traffic flow.
The Highways Agency's trial will run from Junction 61 to Bishop Middleham and from Junction 63 to Lumley Road Bridge.
It affects heavy goods vehicles of 7.5 tonnes and over, which slow down on the southbound carriageway's uphill slope.
When they attempt to overtake, it can block the road and cause delays.
Road users 'frustrated'
The restrictions will operate between 0700 BST and 1900 BST and come into effect on 31 March.
Project manager, Andrew Jennings, said: "The two sections of motorway affected by these restrictions are two lanes wide with uphill gradients on the southbound carriageway.
"When heavy lorries overtake each other on these stretches, it can block both lanes, slowing down traffic for several miles and causing frustration for other road users."
He added that the 18-month trial would allow the agency to assess whether it improved overall traffic flow.