A man killed in a crash on Interstate 79 last week is believed to have fallen asleep while driving. 19-year old Devan Lawson of Ohio was killed in a crash while driving northbound near Elkview on Aug. 4, according to a news release from the Kanawha County Sheriff’s Office. Investigators think he fell asleep while driving and his vehicle left the roadway, entered the median and rolled several times. Lawson was not wearing a seatbelt at the time of the crash and was ejected from his truck. Investigators who reconstructed the accident found no evidence of impairment or excessive speed.