"It seemed like they were provoking the driver to come out", the witness who asked to remain anonymous told the newspaper.
The attack occurred just after 6 p.m. Wednesday on Highway 101 when the Uber drive's white Toyota stopped on the highway for unknown reasons and the group of men surrounded it.
An Uber driver is recovering from a broken leg after taking a serious beating from a biker gang on the highway.
The 35-year-old man, identified by only his first name, Alex, was beaten after more than a dozen men on dirt bikes and all-terrain vehicles surrounded his auto on US Highway 101, according to the San Francisco Chronicle. "These are the types of incidents that really need to get attention and that really need to get prosecuted", the witness said, hoping the bikers are caught.
The motorist pulled to the side of the freeway where he was attacked by the bikers.
Quintana was in fair condition Friday at San Francisco General Hospital, where he underwent surgery to have pins implanted in his left leg. Doctors are waiting for the swelling to go down before performing another surgery.
A 42-second video that has gone viral shows one biker pulling the Lyft driver backward onto the ground.
Police responding to axe attack at Dusseldorf train station
The train station has been sealed off and trains have been diverted from the station while police deal with the incident. The rail station remained shut down, he added. "The whole station is full of police officers".
A local resident who videotaped Wednesday's incident told KNTV-TV one of the bikers swerved toward the motorist - who was driving a white Toyota Camry - and then appeared to fishtail before regaining control of the dirt bike.
Quintana said witnesses gathered around him to offer help.
Authorities have said it wasn't possible to identify the bikers because the motorcycles had no license plates and the gang members wore helmets.
Witnesses to the incident were interviewed and a video showing the altercation was obtained and booked into evidence.
His girlfriend, Cecelia Dunn, told the Modesto Bee: 'They picked an innocent person'. Representatives for the San Francisco-based startup couldn't immediately confirm the victim was an Uber driver.
"I am a Christian and I am trying not to let my heart feel a lot of hate", Dunn said.