The California Highway Patrol is on the lookout today for a pack of stunt-riding ATV and dirt bike riders who put a motorist in the hospital after a roadside altercation this week.

According to, a gaggle of between 10 and 15 helmetless individuals clogged up the southbound lanes of Highway 101 near San Francisco with non-road legal dirt bikes and ATVs around 6:00 pm on March 8. Witnesses told KRON that the riders were weaving in and out of traffic and performing various unsafe stunts as they disrupted the evening commute.

As they swarmed through traffic, a white Toyota Corolla bumped one of the riders and the situation took an ugly turn. As soon as the bike and Toyota connected, a car cut the Corolla off and brought it to a stop. The Corolla driver got out and was instantly mobbed by riders. The riders then knocked the Corolla driver down and beat him mercilessly before fleeing the scene.

CHP officer Vu Williams warned motorists in an official statement to stay in their cars and call for help in dangerous situations like this one.

“Definitely do not try to confront the motorcyclists, ” Williams told . “Do not try to get out, because this is something that could happen. Not only that, you’re on a busy freeway. You never know who’s coming up behind you. So the best thing to do again, call it in, report it, we have units in the area and we’ll respond.”

The Corolla driver was rushed to the hospital with a number of serious but non-life threatening injuries, including a broken leg.