The A19 is closed in both directions after a serious crash.
The Air Ambulance was called to the Southbound carriageway between A1130 Mandale Interchange, Acklam and A174 Thornaby.
Emergency services were called to the scene after a crash involving more than two vehicles.
The road has been closed since 10:30.
The accident is thought to have happened on the entry slip road however police have closed the road to allow emergency services to assist.
Cleveland Police are urging drivers to avoid the route, as it is likely to remain closed for several hours.
Cleveland Police remain at the scene carrying out their investigation work.