The A43 southbound is closed from junction 15A of the M1 in Northamptonshire after a lorry caught fire following a collision with a motorbike.
The fire caused damage to the surface of the road near the Blisworth turn of the A43, which has been closed to allow repairs to be made and the vehicles recovered from the scene.
Diversions are in place and it is not known when the road will be re-opened.
The delays are currently being experienced between junction 15a of the M1 and the A5 Towcester turn of the A43 on the northbound carriageway also.
No one is believed to have suffered serious injuries following the incident at around 3.45pm, but the motorcyclist has been taken to hospital.
Motorists are being advised to avoid the area and use alternative routes while this closure is in place.