Cars and motorcycles using bike lanes to cut around slow-moving traffic is both a hazard and an everyday reality for cyclists in most of San Francisco. It appears that it was with this in mind that Randall Dietel yesterday stopped in a bike lane on Golden Gate Avenue near Taylor Street to film cars using the lane reserved for bikes. He got more than just video. Instead, a man riding a motorcycle through the bike lane pulled up beside him, stopped, and then smacked the camera right out of Dietel's hands. The man then sped off.

This, of course, is not the first time drivers have responded with violence after being called out by cyclists. In May, a driver got out of his car and screamed and spit at a woman after she yelled at him for parking in the Market Street bike lane. On Bike To Work Day, another driver allegedly ran over a cyclist after he allegedly banged her car.

This was also not the first time Dietel had shot video, or "[enforced] the bike lane" as he referred to it, in that location. He has posted several other videos from the same spot and retweeted similar videos shot by others.

The backdrop to all of this is the two cyclists killed by hit-and-run drivers a week ago today. With Mayor Lee calling for stepped-up enforcement following the crashes, it looks like Dietel responded to the call.

“I think what the city needs to be doing is focusing on making it safe for people who are eight to 80 to be able to cycle and get around in the city,” Dietel told CBS 5. "Drivers need to realize that 20 miles per hour is plenty fast enough and that most of the time if you are driving in downtown San Francisco, you’re on a 25-mile-an-hour street.”

Related: Streetsblog Editor Confronts City Employee Parked In Bike Lane