Critical Mass began rather unassumingly, under a less catchy name, the Commute Clot. I went to a San Francisco Bike Coalition meeting in August 1992, and suggested--since there were so many people in bikes downtown, and conditions were so infamously bad--that we gather once a month, make our presence felt to ourselves and the rest of the city, and ride home together. An enthusiastic response was followed within a few weeks by the SFBC's cautious disavowal of responsibility, but the ideas caught on immediately. The first ride drew about 60 and after a full year it is drawing upwards of 600+ per ride.

The name Critical Mass came from Ted White's bike-umentary "Return to the Scorcher" wherein intersection crossing etiquette in China's big cities is discussed as a matter of Critical Mass: the cross traffic waits until it achieves a critical mass and then pushes through, leaving the original stream of traffic to stop and build until it reaches its push-through point. Once a month we are a Critical Mass, filing 3-4 long blocks of San Francisco's Market Street at the tail end of rush hour, and pedaling in a free expression zone temporarily free of engines and exhaust...

- Chris Carlsson, August, 1993. Excerpted from Critical Mass From the Inside Out.