The truck collided with an oncoming car on a road in the community of Lanquart on Monday evening, cantonal police said on Tuesday.
The blade of the snow plough damaged the entire length of the car, police said.
The driver of the car was taken to Graubünden cantonal hospital for a checkup.
Police immediately seized the snow plough truck driver’s licence after he failed a breath test because of earlier alcohol consumption.
He was then subjected to a blood test.
An investigation was launched into the accident.