The A1M in North Yorkshire was closed for nearly seven hours following a serious collision at rush hour on Thursday.
The motorway was closed southbound between junction 53 Scotch Corner and junction 52 Catterick from about 5pm
It was a single vehicle accident, with reports saying a car hit the central reservation.
Firefighters from Richmond, Colburn and Darlington went to the scene. They helped a woman from the vehicle and left her in the care of ambulance crew.
Huge queues of traffic built up. Diversions saw vehicles take the A6055 to re-join the motorway at J52.
Trapped traffic was released by 7.15pm. At 12.03am on Friday morning, National Highways said the southbound carriageway had finally reopened.