If the past and the future meet in the present, then the Critical Mass bicycle phenomenon might be among today's most obvious material or physical manifestations of a past struggling against its future; Of the established order coming up against a certain rolling mass moving for change. ******* On one hand, there are traffic rules. What more concrete example of the need for traditional standards and an authoritative reference for the completion of a task critical to modern civilization is there, than a set of rules on how speeding tons of rolling metal should be managed on a massive scale? ******* On the other hand, there is an alternative vision of how things might be in the years ahead, plus a need for society to find alternatives to modern consumption habits. That alternative vision is expressed in a bicycle ride on the last friday evening of each month, throughout San Francisco, called Critical Mass. ******* Their message is, to put it simply: less cars translates to a healthier planet and healthier people. ******* There’s the nut of it: the past vs. the future or the solid reality against the abstract ideal. ******* On the streets of San Francisco, speaking both strategically and tactically, its the Romans vs. the Huns all over again, an example of traditional military strategies vs. swarming an enemy into submission by using autonomous, undirected and therefore unpredictable groups. ******* Over the years the cat-and-mouse game that they've both played out on the City's streets has led to an uneasy truce of sorts, well, most of the time. ******* Still, the spirit of the unorthodox and unpredictable, the general desire on the part of Critical Mass to shake the cops off their tail whenever possible and slip away quickly, is still very much alive. ******* Critical Mass started in 1992, when someone circulated flyers calling on bicycle riders to gather and ride around town to promote using bicycles instead of cars. About 25 cyclists showed up; Then perhaps another 20 or so others joined them as they rode around San Francisco. ******* In April, 1993, a confrontation between a motorist and a bicyclist in Critical Mass resulted in a mangled bicycle but no injuries, however, police decided it was prudent to begin escorting them around town once a month, in the interest of public safety and keeping the peace. ******* And that's when the dynamics of strategy and tactics between Critical Mass and the SFPD got controversial and interesting. ******* All photographs by Thomas K. Pendergast, taken on March 26, 2010.