Works will get under way next week to create a new underpass on the A1 at Morpeth.
It will form a key part of the junction between the A1 and the new Morpeth Northern Bypass and the works will result in drivers using a new section of road for the first time.
Both northbound and southbound A1 traffic will be diverted from the existing carriageway to use newly constructed lengths of road that will eventually become the slip roads for the new junction.
From Wednesday, drivers will filter off the A1 northbound between the River Wansbeck and the A697 slip road and travel along the new section of road for around one kilometre.
From Friday, June 10, those travelling southbound will leave the A1 just after the Morpeth north turn-off and rejoin before the River Wansbeck.
These changes will be carried out during the preceding nights to minimise traffic delays.
The diversion, which will be in place for several months, should not overly affect traffic flows or journey times as the road is already subject to a single lane 40-mph limit on this stretch and drivers will simply filter onto a new road running parallel to the A1.
Coun Ian Swithenbank, cabinet member for local services, said: “This diversion marks the start of one the next major stages of this impressive engineering project.
“This method of construction using the future slip roads whilst we construct the bridge will allow the works to be carried out much more quickly and safely than other methods and also minimise traffic delays.
“I am pleased to see the excellent progress that is being made with major works to structures and the road starting to take shape all along its length. Once complete, it will open up the area for further economic growth.”
The 2.4-mile bypass is scheduled for completion in March 2017.
More information about the project can be found online at www.morpethnorthernbypass.org