A multiple-vehicle accident on northbound Interstate 405 at about 4 p.m. today at State Route 169 near downtown Renton backed up traffic for about four miles, according to the Washington state Department of Transportation.

All northbound lanes were reopened at about 4:30 p.m., but traffic remained backed up to Interstate 5.

The state transportation department Incident Response Team, fire, aid and the Washington State Patrol responded to the accident.