Westbound traffic on U.S. Highway 36 was slowed for two hours Wednesday after an accident reduced traffic to one lane.

The accident occurred at 1:10 p.m. when Robert E. Gann, 64, of Easton, Mo., was traveling west on Highway 36, three miles east of St. Joseph. His 1996 Dodge was struck from behind by a 1985 Ford box truck, owned by the Missouri State Highway Patrol maintenance department. The Dodge overturned off the north side of the highway. The Ford traveled off the south side of the road, coming to rest on its wheels, the Highway Patrol said.

Mr. Gann and his grandson, Daniel A. Gann, 7, from Clarksdale, Mo., were transported to Heartland Regional Medical Center with minor injuries. Mr. Gann wasn’t wearing a seat belt at the time of the accident, Daniel was.

The driver of the Ford, Jeffrey E. Rook, 46, of Centertown, Mo., was cited for careless and imprudent driving.