The 43-year-old driver of a pickup truck was in custody Sunday night for investigation of vehicular assault after the vehicle went through a guardrail, rolled off Interstate 5 in Federal Way and trapped the driver and a passenger inside, Trooper Chris Webb said.
Webb said just before 7:30 p.m. that the crash happened at I-5 and South 288th Street.
The passenger was taken to Harborview Medical Center, he said.
Webb said the driver was being investigated for DUI, and that 288th would be at least partially closed for several hours, and possibly lanes of southbound I-5, too.
Webb initially said the driver was a third person who had try to flee the crash on foot, but Webb later said that the vehicle had two occupants at the time of the crash, and that troopers believed the actual driver had tried to mislead them by saying someone else had been behind the wheel.