Motorists are being moved off the A149 and on to part of the new Sainsbury’s link road at Lynn while construction of a new roundabout is carried out.
The switchover onto the newly-surfaced western part of the roundabout at the A149 Queen Elizabeth Way end of the new £7.5m link road should have happened earlier.
But Norfolk County Council’s resident engineer Quentin Brogdale said it was affected by a mixing plant breakdown which restricted deliveries of asphalt to the site on Friday and delayed the switch until late on Sunday night.
Mr Brogdale said that most of the new road, including the roundabout at the Scania Way end on the Hardwick Industrial Estate, has been surfaced up to base level, and should be ready to open to traffic on November 20.
Surfacing has been completed on the western side of the A149 roundabout so that it can be used temporarily to take two-way traffic from the main road during construction of the eastern side.
Mr Brogdale said: “It is important that drivers observe the 30mph speed limit on approach and proceed with care through the site in accordance with temporary signing.
“It is likely that by Wednesday, November 14, traffic lights will need to be used overnight to allow the existing road surface to be reshaped and resurfaced to suit the new roundabout.
“The final surface course will also be laid along the link road and at most of the Scania Way roundabout this week.”