Vehicle driving wrong way led to collision, major backup on I-5 south in Seattle

All lanes of Interstate 5 (I-5) south in downtown Seattle reopened Monday after a multi-vehicle collision in the early morning closed the highway for over four hours.

The Washington State Department of Transportation (WSDOT) reported on X, formerly known as Twitter, at 9:57 a.m. Monday that all lanes of I-5 south near Mercer Street had reopened after the early-morning crash.

The agency said on X the collision happened just south of Mercer Street at approximately 5:30 a.m. and was blocking all southbound lanes. Traffic had been being diverted to Mercer Street.

Washington State Patrol Public Information Officer Trooper Rick Johnson reported on X earlier Monday morning the “collision (involved) a semi and 2 other vehicles with multiple individuals sustaining injuries in both vehicles.”

Johnson added the causing driver spun out and caused the collision and “that driver is in custody for investigation of vehicular assault due to suspected impairment and injuries sustained by occupants of the other vehicle.”

Later Monday afternoon, Johnson wrote on X the vehicle that caused the incident “was traveling the wrong way prior to the collision.” He added that it is, as of now, “undetermined whether they got on the wrong way or made a U-turn to go the wrong way.”

WSDOT had been providing regular updates on the progress of clearing the road all morning. As of 8:38 a.m., all lanes were blocked following the earlier collision and the agency did not know when lanes will reopen.

WSDOT said close to 7 a.m. that it “completed an early switch of the I-5 express lanes to southbound.”

This is a developing story. Please check back for more updates.