Drivers are being warned of months of disruption on the A12, with lengthy diversion routes in place while major roadworks are carried out.
National Highways will begin resurfacing and repainting road markings between Chelmsford and Colchester from July 13, with work taking place on weeknights between 9pm and 5am until October.
Closures will be carried out in phases to minimise disruption, but motorists could face diversion routes of around 25 miles during the works.
The first phase will see the northbound A12 closed between junctions 19 and 22 from Monday, July 13, to Friday, August 1.
This will be followed by a southbound closure between junctions 25 and 23 from Monday, August 10, to Friday, September 12.
In the final phase, the northbound carriageway will be closed again between junctions 19 and 25 from Monday, September 14, to Friday, October 10.
National Highways said the closures are necessary to allow resurfacing and road marking improvements to be completed safely.
A spokesman said: "We’re starting our main maintenance work on the A12 from Monday 13 July, resurfacing the road and refreshing the road markings between Chelmsford and Colchester.
"We've a number of planned road closures, starting from 13 July until October 2026 on weeknights only, between 9pm and 5am, weather permitting."
Diversion routes will be in place while the carriageways are closed which will be as follows:
If you wish to travel northbound on the A12:
- exit the A12 at junction 19 (Borham)
- onto the A131 (Beaulieu Parkway/Channels Drive)
- at the roundabout, turn right onto the A131
- continue to the A120 (Great Notley)
- then onto the A120 towards Colchester
- then join the A12 at junction 25 (Marks Tey), before continuing on your journey
If you wish to travel southbound on the A12:
- from the A120, exit at junction 25 (Marks Tey)
- follow the A120 to Great Notley
- then leave the A120 onto the A131
- at the roundabout, turn right onto the A131 and continue to junction 19
- before joining the A12 and continuing on your journey
