A one vehicle accident in Mercer County Tuesday night, ended with the driver flown for treatment. According to the Highway Patrol, Nathan Allen, 38, of Trenton was Southbound on Highway 65, just South of Highway 136 in Princeton, when he ran off the right side of the highway, struck a retaining wall causing the vehicle to become airborne. The vehicle landed front bumper first and overturned onto it’s top. Allen was seriously injured and flown to Methodist Hospital in Des Moines.