Washington State Patrol detectives, with assistance from Seattle Police and State Patrol .
Police named the suspect as Fred Colvin of Seattle. Police believe he was involved in a domestic dispute with his girlfriend that night, during which Colvin allegedly shoved the woman into the roadway on State Route 900 (Martin Luther King Jr. Way) just east of S. 129th Street.
Colvin's girlfriend sustained "significant" injuries after being struck by a Toyota SUV that was traveling at normal speed, according to police.
Colvin has been booked into the King County Jail for investigation of Assault 1st Degree.
Detectives received several tips following the collision which allowed them to locate the suspect around 9 a.m. Friday morning.
*Editor's Note: Information provided by the Washington State Patrol.