DES MOINES, Iowa (AP) — The Iowa State Patrol says the driver of a car that crashed into a semitrailer on Interstate 80 in Adair County fell asleep at the wheel. A passenger, 17-year-old Stephanie Pathammavong, of Des Moines, was killed in the Sept. 26 accident. The patrol says the driver, 21-year-old Boby Vangkham, of South Sioux City, Neb., told investigators he was “daydreaming and fell asleep.” Vangkham lost control of the eastbound car, which ended up in the westbound lane and collided with the semi. The accident, which happened shortly before 3 p.m., closed the westbound lanes for several hours.