Dennis Kling of Kansas City, Kan., was pulling a double trailer through a construction zone with a 2001 Volvo truck when it ran off the interstate south of Oklahoma 15 about 3:15 p.m., the Oklahoma Highway Patrol reported.

The truck hit a fence and a tree, troopers said. No other vehicles were involved. It was not immediately clear why Kling, 57, lost control of the vehicle, but the Highway Patrol reported that a medical condition might have affected his driving.