A major collision shut down two lanes of the Bay Bridge headed eastbound, causing delays and leading to a death Sunday, the CHP said.
The crash involved multiple vehicles, and a passenger in one has been pronounced dead, officials said.
This comes after a group of several motorcyclists began driving the wrong way on the Bay Bridge Sunday afternoon, apparently sparking a series of collisions.
Law enforcement officers made stops and some arrests.
CHP officials said they had reports of several hundred motorcyclists throughout the San Francisco Bay Area traversing city streets and highways starting around 2 p.m., leading to several incidents throughout the region.
Around 5 p.m., a smaller group splintered off of the larger group and attempted to cross the bridge.
CHP units were there to ensure they would not do stunts or take over the freeway.
Upon seeing the officers at the foot of the bridge, the motorcyclists began going the wrong way toward the Sterling onramp and 4th Street exit, officials said.
They eventually reentered the bridge from westbound I-80 at Fremont Street in San Francisco going eastbound in the westbound number five lane, the one on the far right.
They continued driving eastbound using all the westbound lanes in heavy traffic, the CHP confirmed.
One of the motorcyclists was involved in a collision and fled from his bike, becoming a passenger on another motorcycle.
Additional CHP units encountered the wrong way motorcyclists on the incline, and they fled in many different directions, officials said.
The motorcyclist with the passenger that had fled the crash turned around and continued westbound, exiting the bridge via the Treasure Island ramp.
They attempted to hide on the north side of the bridge just beyond the ramp, authorities said.
As CHP units approached where they were hiding, they tried to reenter the westbound lanes by jumping the concrete wall.
The passenger was thrown off the bike into the eastbound fast lane at the east end of the tunnel, where he was struck by a pickup truck and eventually pronounced dead at the scene after officers attempted CPR.
There were at least two other incidents involving motorcyclists in which officers were injured.