PIERRE, S.D. – (DRG News) A Rapid City man died in a one-vehicle accident that occurred today in Lyman County-about three miles north of Vivian on a gravel road.  The South Dakota Department of Public Safety says 51-year-old Kevin Joseph Casey was northbound, driving a 2010 Dodge Ram 2500 on 293^rd Avenue when the vehicle left the roadway and rolled.  Casey was not wearing a seatbelt and was dead at the scene.  The accident occurred sometime between midnight and 7:40 a.m. this morning.   The South Dakota Highway Patrol continues to investigate the fatal accident and the Lyman County Sheriff’s Department assisted at the scene this morning.