Drivers have been warned to "expect significant delays" as a series of weekend closures on the A47 in Norwich begins this evening.
A major junction at Postwick will close from 8pm tonight until 6am on Friday.
It will then close again at 8pm on Friday until 6am on Monday April 20.
It is the first of three weekend closures affecting this weekend, next weekend and the weekend from 8pm on May 8 to 6am on May 11. The road will remain open over the first May Bank Holiday weekend.
The closures will allow eight large bridge beams to be lifted into place as part of a major £19m upgrade of the junction. The bridge will serve a new Postwick hub junction and a new park and ride.
A diversion will be in place via the A146, A143, A12 to rejoin the A47 at Vauxhall roundabout.
Tim Ellis, project manager for Norfolk County Council, said, because the work involved a 1,000 tonne crane and 75 tonne beams, it was impossible to avoid causing disruption.
Details of the road closures:
Weekend One – April 17 to 20
The westbound carriageway, towards Dereham, will close at 8pm on Friday April 17. The eastbound carriageway will be kept open until traffic has cleared after the Norwich City v Middlesborough match (about 11pm). The road will reopen no later than 6am on Monday 20 April.
Weekend Two – 24 to 27 April
Closure of both carriageways at 8pm Friday 24 April. There will be delays on the westbound diversion route while beams are moved from the site compound on to the A47 itself. Road to reopen no later than 6am Monday 27 April.
Weekend Three – 8 to 11 May
Closure of both carriageways at 8pm Friday 8 May. Road to reopen no later than 6am Monday 11 May.
The Postwick park and ride will be closed during each of the weekends. The nearest alternative will be the Harford park and ride at the junction with the A140.
For further information and details on diversions click here.