(Polk County, Iowa) – A man from California was struck and killed by a semi tractor-trailer late Monday night, in Polk County. The Iowa State Patrol reports a semi driven by a man from Sacramento, CA, was westbound on Interstate 80 near Altoona at around 10:30-p.m., when 18-year-old Davis Cooper, of Pasadena, CA, entered the roadway and was hit. Cooper died at the scene. It’s not known why he was walking along the Interstate. The Patrol said Cooper was parked at a convenience store nearby, before entering the interstate on foot.