A12 Chelmsford to Colchester maintenance
We're resurfacing and maintaining the central reservation on the A12 in Essex between junction 20b (Hatfield Peverel South) to junction 22 (Witham North), and from junction 24 (Kelvedon North) to junction 25 (Marks Tey) from 11 May to October 2026.
Planned road closures start 11 May 2026
We’re starting maintenance work on the A12 from Monday 11 May, resurfacing the road and refreshing the road markings between Chelmsford and Colchester.
We have a number of planned road closures on the slip roads starting from 11 May on weeknights only, between 9pm and 5am, weather permitting.
Closures and diversions
To work safely, we'll need the following road closures:
Monday 11 May - A12 northbound junction 20B (Hatfield Peverel North Interchange) entry slip road
Diversion:
- Continue south on the B1137 to junction 19 (Boreham Interchange)
- turn around
- and rejoin the A12 northbound
A12 junction 20b northbound entry slip closure and diversion map
Tuesday 12 May - A12 northbound junction 21 (Witham South Interchange) entry and exit slip roads
Diversions
Exit slip road:
- Continue north to junction 23 (Kelvedon South)
- turn around
- then travel south to junction 22 to access local roads
Entry slip road:
- Travel north on the B1389 to junction 22 (Colemans Interchange)
- and join the A12 northbound there
A12 junction 21 northbound entry and exit slip roads diversion map
Wednesday 13 May & Thursday 14 May - A12 northbound between junction 21 (Witham South) and junction 22 (Colemans Interchange)
No diversion required, as one lane remains open.
Tuesday 19 May & Wednesday 20 May - A12 northbound junction 22 (Colemans Interchange) entry slip road
Diversion:
Travel north on the B1389 to junction 21 (Witham South Interchange) and join the A12 northbound there.
A12 junction 22 northbound entry slip closure and diversion
Please remember that closures can change at short notice. You can check the latest information on our daily closures page or find live travel information on our Traffic England. Our travel alerts give details of live incidents on our network.
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