Authorities say a driver suffered serious injuries in a one-vehicle crash in Dubuque County early Tuesday morning. 54 year old Gregory Mulert of Peosta was taken by ambulance to a hospital for treatment of serious injuries. According to the Dubuque County Sheriff’s Department, Mulert was traveling west on U.S. Highway 20 at the overpass for Bobcat Road at around 4:29 a.m. Tuesday when his vehicle left the roadway and struck a support column for the overpass. The collision caused Mulert’s vehicle to overturn.