The accident was reported around 11:35 a.m. near Vermont Street, CHP Officer Peter Van Eckhardt said.
An ambulance that happened to be traveling past the crash site en route to the hospital stopped to assist, a San Francisco fire dispatcher said.
At least one person involved in the collision was transported to a hospital.
A Sig-alert was issued for the highway 12:03 p.m. but the roadway was cleared and lanes reopened by 1 p.m., Eckhardt said.
