Police have thanked motorists who contacted them about the incident on the westbound carriageway
An 84-year-old man is in a critical condition in hospital after driving the wrong way on the M1 and colliding with a police vehicle.
The Volkswagen Polo car struck a stationary police car between the Lurgan and Moira junctions at 04:50 GMT on Monday.
A police officer was injured and taken to hospital.
The Police Ombudsman has been informed of the incident.
A spokesperson for the Southern Trust said the 84-year-old man remains in a critical condition at Craigavon hospital.
