The A1 at Newark is closed in both directions after a serious crash.
Police were called to the crash involving a car and a lorry between the A46 and B6326.
Reports indicate that the lorry overturned following the collision.
Lincolnshire and Nottinghamshire Air Ambulance also attended the scene.
The crash happened on the northbound carriageway but one of the vehicles appears to have gone through the central reservation.
The road is expected to be closed for several hours.
Motorists should avoid the area if possible and follow diversions.