OAKLAND (CBS SF) — A multi-vehicle crash on westbound 80 near Yerba Buena Island early Friday shut down two lanes on the Bay Bridge, slowing the commute into San Francisco into a crawl and backing up traffic through the MacArthur Maze beyond Ashby Ave., authorities said.

According to the California Highway Patrol, emergency crews were dispatched to reports of a crash on the bridge at 4:50 a.m.

Arriving crews discovered that the collision involved four vehicles including a bus. Caltrans cameras showed a massive backup at the toll plaza and a Sig Alert was issued a warning to commuters to seek other routes into San Francisco.

Injuries were reported in the crash. All lanes were reopened by 7:25 a.m. but the backup and slow traffic was expended to continue through the morning commute.