The A1(M) northbound is currently closed between junction 48 (Boroughbridge) and junction 49 (Dishforth) due to a serious collision.
Police were called to reports of a collision involving two HGVs at about 5am this morning.
Emergency services are working at the scene. The road is expected to remain closed for some time.
Road users are urged to avoid the area, use alternative routes, and allow extra time for their journeys.
Motorists caught in traffic are urged to remain in their vehicles and stay clear of the hard shoulder at all times. This is for their own safety, and that of the emergency services.