SAN FRANCISCO (KRON) – A motorcyclist was killed in a harrowing chain-reaction crash involving multiple DUI drivers in San Francisco, according to the California Highway Patrol.

The deadly wreck happened at 3:28 a.m. Tuesday on a freeway ramp connecting Highway 101 southbound to I-80 eastbound.

CHP investigators determined that the incident began when a Nissan sedan crashed and blocked one lane of traffic.

A motorcyclist then lost control of his bike while he tried to avoid colliding with the Nissan, the CHP said.

The motorcyclist crashed into a wall, was ejected, fell 30 feet down to I-80’s westbound connector ramp, and landed on top of a moving car.

“The motorcyclist struck the wall and the rider was ejected over the wall. At that time, a Honda sedan was traveling on I-80 westbound to the US-101 southbound connector ramp. The motorcyclist fell on top of the Honda and the driver of the Honda slowed to a stop as the motorcyclist came to rest laying on the roadway,” the CHP wrote.

The motorcyclist was run over by at least one, “or possible more,” vehicles, the CHP said.

While the Honda was stopped and blocking traffic lanes, a Subaru Forester approached the rear of the Honda. The Subaru driver was unable to slow down in time before ramming into the Honda.

The drivers of the Nissan and Subaru were both arrested and booked on suspicion of driving under the influence, according to the CHP.

The motorcyclist was pronounced dead at the scene.

Highway 101 southbound lanes were closed for five hours for the investigation.

Any witnesses or motorists who may have been driving through the area at that time is asked to contact Officer Israel Garcia at the CHP San Francisco Area office at (415) 557-1094.