The A1 has been closed in both directions after a car fell onto the central reservation from a flyover.
At approximately 10.30am on Friday, a vehicle driving on the A177 flyover came off the road and landed on its roof in the central reservation of the A1(M) below.
A Durham Constabulary spokesperson said emergency services remain at the scene but that the driver of the vehicle and a passenger have both been freed from the wreckage.
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"The driver of the car freed themselves from the wreckage and the passenger was cut free. No other injuries have been reported.
"Emergency services are on the scene and both the A1(M) and the A177 are closed in both directions."
A North East Air Ambulance spokesperson confirmed they were called to the scene and one person was flown to hospital.
A spokesperson from the North East Ambulance Service said: "We received a call at 10.33 this morning to reports of a road traffic incident on the A1 northbound in County Durham.
"We dispatched one ambulance crew, three crews from our Hazardous Area Response Team (HART), and an officer, and requested support from the Great North Air Ambulance Service (GNAAS).
"Two patients were taken to hospital for further treatment; the first patient was taken by road to the University Hospital North Durham (UHND), and the second patient was flown to the Royal Victoria Infirmary Major Trauma Centre (RVI MTC)."
Durham Constabulary also confirmed that the A1 and A177 is likely to remain closed for a considerable time.
Drivers are urged to avoid the area and find an alternative route if possible.