'They were running amok': Hundreds of dirt bikes and ATVs cause mayhem on San Francisco's Bay Bridge on Sunday as they swarm both decks - closing two lanes and leaving one biker dead after a collision

A passenger on a motorcycle died on Sunday after a crash involving multiple vehicles amid a swarm of motorbikes and ATVs driving the wrong direction on San Francisco's Bay Bridge.

Multiple videos posted online and shared by news outlets showed a wave of motorcycles, dirt and quad bikes weaving in and out of traffic on the bridge that runs between San Francisco and Oakland.  

As night fell, some bikes were recorded going the wrong way against the flow of traffic in an apparent attempt to elude California Highway Patrol officers. 

Video from Dr Ada Wells shows bikers popping wheelies on the Bay Bridge in San Francisco on Sunday afternoon 

Hundreds of people riding motorcycles, dirt bikes and ATVs caused chaos in San Francisco, disrupting traffic and leading to major delays  

'I don't know what's happening, but they're going the wrong way on the bridge,' a woman says in one video. 'It seems really dangerous.' 

The CHP began receiving reports of several hundred bikers 'running amok' in San Francisco at around 2pm on Sunday, CHP SF Public Information Officer Mark Andrews told Bay City News Service, as reported by MercuryNews.com.

Some bikers were caught on video doing stunts, including popping wheelies, in the middle of heavy daytime traffic. 

Shortly after 5pm, a group of more than a dozen motorcyclists entered the Bay Bridge riding eastbound.

The situation took a dangerous turn after dark, when a group of some 15 bikers entered the Bay Bridge between San Francisco and Oakland, riding eastbound 

When the bikers saw CHP patrols, they turned around and headed the wrong way, going west

When the bikers saw CHP patrols, they turned around and headed the wrong way, going west.

One of the motorcyclists, described only as a 20-year-old man, crashed his dirt bike and fled on foot.

He was picked up as a passenger by another dirt bike driver, who then made a turn and headed west in the eastbound lanes.

As the driver approached a tunnel, he decided to take the exit onto the Treasure Island ramp and hide from CHP officers on the north side of the bridge. 

As CHP units approached the bikers' hiding place, the driver tried to jump a concrete median barrier in a bid to reenter the westbound lane, which caused his passenger to be thrown off the bike.  

A deadly collision took place after a 20-year-old man trying to evade CHP officers jumped onto another driver's dirt bike as a passenger (not pictured) 

A swarm of bikers is seen clogging the bridge during heavy evening traffic. CHP officers were on the bridge, watching out for bikers doing stunts 

Several accidents that took place on the bridge on Sunday left CHP officers injured 

The 20-year-old man landed in the middle of the eastbound fast lane, where he was was struck and killed by a pickup truck.

The driver of the dirt bike, who was injured in the collision, was arrested. He has not been named as of Monday afternoon.

The mayhem on the bridge led to two other incidents in which CHP officers were injured. 

The commotion shut down two lanes on the bridge for several hours and caused a major traffic backup. All lanes were reopened by 9.10pm.