A man is dead after the commercial truck he was driving rolled over early Sunday, and state troopers suspect a medical event may have played a role.

Curtis Keelin, 50, was southbound on WY 530 near milepost 41 in Sweetwater County before the crash. At about 12 a.m. Sunday, his truck left the roadway to the west, according to a crash report from the Wyoming Highway Patrol.

The truck continued parallel to the highway for about 300 feet before hitting a culvert. After hitting the culvert, the truck went another 200 feet before rolling onto the driver's side.

Keelin was not wearing his seat belt at the time of the crash, the report indicates. The road was dry and weather was reportedly clear that night.

An autopsy was scheduled for Wednesday to determine whether Keelin suffered a medical event before the crash. The only contributing factor listed in the report was a possible, unspecified medical condition.