DORCHESTER COUNTY, S.C. (WCSC) – The South Carolina Highway Patrol is investigating a deadly single-vehicle accident that happened about five miles north of Summerville. Sgt. Tyler Tidwell says a car was traveling north on US-17 alternate near Clubhouse Road at approximately 11:35 Saturday night when it ran off the road to the left, then the right, struck a ditch, then hit a utility pole.