The A30 Eastbound is partially blocked after an accident.
Police say the incident happened near Hayne Bridge Road (Stowford Cross).
Emergency services are at the scene and the accident is affecting traffic between Launceston and Okehampton.
Devon and Somerset Fire and Rescue says it received reports of a one-vehicle road traffic collision where a car had rolled over, coming to rest on its side on an embankment and trapping two occupants.
"Within minutes of the first crew arriving this was confirmed to be the case and set to work stabilising the vehicle, before preparing to extricate the 2 casualties.
"At 15:05hrs they confirmed the incident was under control and the casualties had been released, using power rescue tools and small tools. Once extricated into the hands of paramedics, they were both conveyed to hospital via land ambulances, whilst we made the vehicle and scene safe. Duty of care was then left with the Police."