Drivers have been warned of long diversions while one of the busiest parts of the A47 is closed for roadworks.
Highways England is resurfacing a section of the trunk road between North Tuddenham and Honingham.
The work is scheduled to be carried out on four weekday nights between 8pm and 6am from today, September 11 to Monday September 16.
While the road is closed, signed diversions will be in place which have to be on a similar class of road rather than local routes.
For eastbound traffic, the diversion will start at Swaffham and ve via the A1065 to Fakenham, the A148 and then the A1067, A140 and Dereham Road before re-joining the A47 at Longwater.
The Highways Agency (HA) said it would add about 30-40 minutes to usual journey times.
Westbound traffic will be diverted down the A11 to Thetford and then along the A134 and A1065 to Swaffham. This is expected to add 20-30 minutes to journeys.
Access to emergency vehicles will be maintained on the A47 while the work is done, while bus company First said its services will also be escorted through the works.
A HA spokesman said: "These road improvements are necessary to maintain the strategic road network along the A47. This will add benefits such as a better road surface, safety improvements and an improved journey for our customers."
The agency said the roadworks were subject to weather conditions and local people would be notified of any changes to the dates.
Anyone with queries about the work can ring 0300 123 5000 or email info@highwaysengland.co.uk.
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