A truck driver died early Wednesday when his 18-wheeler overturned on State Highway 14 near Groesbeck, a Texas Department of Public Safety spokesman said.

Thomas Floyd Hobbs, 59, of Caldwell, was driving north on Highway 14 about 12:30 a.m., when, for unknown reasons, he drove off the right side of the roadway and into a ditch, causing the tractor-trailer to roll, the spokesman said.

The vehicle came to rest upside down, the spokesman said. Hobbs was pronounced dead at the scene.

His body was sent to the Tarrant County Medical Examiner’s office for an autopsy, the spokesman said.