A single-vehicle rollover crash left one person dead Monday evening on a highway near Casper.

Gary Stewart, 65, was northbound on Highway 257 in a Pontiac before the crash occurred near milepost 5.5 shortly after 6:30 p.m., according to a crash report from the Wyoming Highway Patrol.

The vehicle went off the right side of the highway before Stewart overcorrected, sending the Pontiac back across the highway. The vehicle went off the left side of the roadway before rolling one and a half times, coming to rest on its roof.

Stewart, who was not wearing a seatbelt at the time of the crash, was pronounced dead at the scene.

Speed and alcohol use are being investigated as possible contributing factors, according to the Patrol's report.

Weather was overcast and the road surface was dry at the time of the crash.