A serious crash, believed to be a collision between a tanker and a motorcyclist at the roundabout at Carkeel, has closed the A38 with motorists being diverted to the Torpoint Ferry instead.
The road is shut eastbound at Trerulefoot and westbound at Carkeel.
Police are advising motorists not to use St Germans as a cut through.
In addition, the Saltash Tunnel is closed westbound and traffic is being diverted through the town centre.
More top news
Barry Pring died after celebrating his first wedding anniversary with his wife. His family believe he was killed for his money.
Devon Air Ambulance is warning people about the dangers of using laser pens, after one of its helicopters was targeted on an emergency call.
The parents of a missing man from Weston-super-Mare have made an emotional appeal for him to "come home" after he disappeared ten days ago.