A 41-year-old Williston man was found dead Tuesday morning at the scene of a car crash in Prairie County north of Terry. 

The Montana Highway Patrol was alerted to the crash at around 4:30 a.m., according to a crash report provided by MHP dispatch. 

The man had been southbound on Secondary Highway 253 driving a vehicle attached to a trailer which was hauling another vehicle.

In the area of mile marker 18 the vehicle drifted off the roadway, hit a guardrail on a bridge and then went off the road, rolling at least one-and-a-half times. The collision separated the vehicle from its trailer. 

The man was deceased when MHP arrived at the scene of the crash. 

Road conditions were described as snow on the shoulder of the road. Drugs and alcohol are suspected as possible factors in the crash, which remains under investigation.