RELATED: Highway 101 road rage victim helping CHP find suspects
These are difficult investigations as these dirt bikers normally wear masks, covering their faces and have no license plates. Police are relying on video tape and information from witnesses at this time.
In the case of this brutal attack, the California Highway Patrol is the lead investigative agency, while the San Francisco Police Department is assisting them.
Investigators believe some of the suspects are from the Bayview District and belong to one of the gangs. "There are a number of officers throughout our district stations. We've had contact with some of these folks on the bikes, so they know who some of them are," San Francisco Police Dept. Sgt. Mike Andraychak said.
It was a brutal attack captured on cellphone video.
Full video of the fight:
Video captured 10 to 15 men on dirt bikes and all-terrain vehicles, zigzagging through evening commute traffic on Highway 101 near the Cesar Chavez exit. The bikers are also seen surrounding a Lyft driver's car, breaking his windows and pummeling him to the ground when he got out of the car.
Alex Quintana is now in a hospital bed with a broken nose and fractured leg.
Police spokesman Mike Andraychek says dirt bikers have been causing trouble for the past year and a half.
Our partners at Hoodline have been tracking these incidents. Recent Instagram video shows bikers performing stunts at an apartment complex in the Lower Haight neighborhood.
RELATED: Residents concerned over dirt bikers in SF's Lower Haight area
"I think they're a bunch of scumbags," Daddy's Barbershop owner Arlen Lasater said.
Lasater witnessed a large group doing doughnuts on 18th and Castro streets in early December, leaving skid marks on the recently replaced rainbow crosswalks. And they did it brazenly in full view of police. "Everybody was watching them do this, including two officers of SFPD sitting at a corner inside a car that was watching them," Lasater said.
Lasater asked the officers why they didn't go after them? "Basically that they couldn't chase them. It's against the law," Lasater said.
"The policy for pursuits limits us to violent crimes, violent felonies in particular and traffic violations don't fall within the perameters of the pursuit policy," Andraychak said.
But Andraychak says if this happened on city streets, officers would be able to chase them since it was a violent crime.
A GoFundMe campaign has been set up to help Quintana.
Click here if you'd like to help make a donation to help him and his family.
The CHP is now reviewing video of the altercation in the hopes of tracking down the suspects who fled the scene, and are asking anyone else who may have witnessed the incident to contact them at 415 551-4100.