Early morning crash backs up traffic heading out of San Francisco

SAN FRANCISCO (KTVU) --  The CHP is trying to determine if weather contributed to a four vehicle crash that backed up traffic heading out of San Francisco.

The pileup happened just after 3 a.m., on Interstate 80, near the First Street onramp, towards the Bay Bridge.

At first, the CHP shut down all eastbound lanes.

They later opened two lanes, and then around 6:15 a.m., the CHP announced they reopened the entire road.

The four vehicles included a big rig and a truck.

The CHP says the most serious injury was a sprained or broken ankle.