A key part of the project to dual the entire A11 road between Norwich and London is set to open on Monday 28 April.
For the first time, the bypass around the village Elveden in Suffolk to south of Thetford, will be open to traffic.
The Highways Agency says: "The new bypass will run with one lane open in each direction, and with a 40mph speed limit, between Chalk Hall Farm to near the end of the scheme, just before Thetford roundabout."
Part of the A11 is still closed after a crash involving two cars and a lorry near Mildenhall.
Police, fire and air ambulance services are still at the scene and a woman is believed to have suffered serious injuries.
The collision happened shortly after 11am.
The stretch of road between the Fiveways roundabout and the Elveden crossroads has been closed.
Diversions are in place, but drivers have been warned to expect major delays.
Delays are expected on the A11 Southbound from Heath Road (Snetterton Circuit) to A14 / A1304 (Newmarket Bypass) due to an abnormal load.
A small convoy including a large stainless steel vessel (two lanes wide) will set off around 9.30am today (Wednesday 26 March), being escorted down the A11 to the A14 and then east into Suffolk.
The narrow Elveden section and roadworks area are likely to be worst affected.
There will be an abnormal load travelling through Norfolk and Suffolk on Wednesday.
The steel tank will be escorted from the A11 at Snetterton to the Cambridgeshire border of the A14 from 9.30am.
Delays are expected through the roadworks at Elveden.
The A11 will be shut to northbound traffic approaching the Fiveways roundabout at Barton Mills in Suffolk from ten o'clock tonight until 6 o'clock Monday morning.
It's the second weekend of closures while work to re-structure the roundabout takes place, as part of the dualling of the A11 up to Thetford.
Diversions via Red Lodge and Bury St Edmunds will be in place
The A11 Northbound is blocked and there is stationary traffic due to a serious accident, a car and a bicycle involved between B1085 (Red Lodge Turn Off) and A1101 Mildenhall Road / A1065 (Fiveways, Barton Mills). The accident is near the Worlington exit.
St. Stephens Road (A11) in Norwich is blocked in both directions after an accident near Chapel Field Road / St. Stephens Roundabout. The police are directing traffic.
The A11 is closed in both directions due to an overturned vehicle at A1101 Mildenhall Road / A1065 (Fiveways).
Suffolk police are appealing for witnesses to a crash between a Rover and a BMW on the A11 at Worlington, near Newmarket. The elderly couple in the Rover have been taken to Addenbrooke's Hospital in Cambridge with serious injuries. Five people in the BMW all suffered minor injuries.
Officers want to speak to anyone who witnessed the collision or saw the manner of driving of the vehicles beforehand. The Rover had entered the dual carriageway from Newmarket Road.
Contact Sgt Julian Ditcham at the Roads Policing Unit on 101.