Just before 7 a.m. today on south bound Interstate 5 Washington State Patrol responded to reports of a one car collision with a barrier next I-405.
The incident happened in the HOV lane and when troopers arrived on scene, the female passenger was unconscious but breathing, according to Trooper Rick Johnson.
He said the fire department determined she was having seizures and that she must have hit her head.
She was transportated to Harborview Medical Center.
There are currently no updates on her condition.
Johnson said the troopers on scene were unable to determine if the driver, a 24 year old female, was impaired or not. He added she was arrested for investigation of Vehicular Assault.
She was not injured.
He said a blood warrant was obtained and a sample was set for analysis.