In the following months, the ride grew steadily, hitting a couple of hundred by February 1993, and still there was no police presence. I think there may have been one motorcycle cop who came upon us during those months and just rode on. In April 1993 it changed though. The ride had grown to several hundred cyclists, and those of us who were publishing the monthly "Critical Mass Missives" and preparing proposed routes with maps, writing flyers, handing out stickers (all under the happy neologism of "Xerocracy ") were already worried about the culture of the ride. Too many people were bleating that Orwellian chant "Two Wheels Good, Four Wheels Bad!" and admonishing motorists in an entirely unpleasant self-righteous moralistic tone.
Behaviorally, we already had identified the "Testosterone Brigade" as a problem, young men who seemed to be looking for confrontation, perhaps exercising unresolved anger with their parents by taunting motorists or deliberately riding into oncoming traffic. Another group was dubbed the "snails" because no matter how often we stopped at the front to give everyone a chance to "mass up," a bunch of folks would just dawdle way at the back and never catch up. This led to long stretches of thinly-occupied streets, where just a few cyclists were noodling along. In April 1993 in just this kind of scenario, a motorist tried to cross Market to Guerrero and when cyclists surged in front to block him, he hit one girl. Her bike was totaled, ending up under his car, which careened into a hydrant on the corner while he was trying to escape. The girl was not physically harmed luckily, but her boyfriend, not knowing that she wasn't under the car, reached in and took the keys out of the ignition. The cops came up and arrested the girl and her boyfriend and let the motorist go, treating him as the victim, even though it was widely felt by all present, including bystanders on the street, that he had behaved with homicidal intent.
Through the mid-1990s the ride continued to grow rapidly, reaching into the thousands by the summer of 1996. During this time, the police had assigned dozens of motorcycle cops to ride herd, a small squad of them often trying to stay in front, only to be thwarted by the spontaneous redirection of the ride from within. (Around 100 of the earliest riders had by then broken off for a more social and informal ride that met at South Park and only occasionally intersected the larger Critical Mass during late 1995-1996, many feeling that the ride had become boring and predictable.) In August 1996 the Cycle Messenger World Championships  came to San Francisco, and at an extremely chaotic and raucous ride at the end of that month, two-three thousand Critical Massers were swirling all around town, some heading back towards the bay for a big benefit at the Maritime Hall, others just lost in the chaos, trying to follow the published route to Golden Gate Park, or following other cyclists in directions unknown. It was wild and fun, but I recall my partner and our then 12-year-old daughter had an unpleasant evening due to too many confrontations, heavy-handed policing, and all around high tension.
In June 1997, rumor has it Mayor Willie Brown got stuck in his limo during Critical Mass. He was soon fulminating in the press about how something had to be done! He tried to bring Critical Mass representatives into a meeting (I was invited and refused to go) and managed to get some SF Bike Coalition board members to show up. His pet supervisor at the time was Michael Yaki, and it was Yaki who appeared on the steps of City Hall after the meeting impersonating Neville Chamberlain in 1938 ("peace in our time!"), waving a piece of paper which he claimed was an agreement with Critical Mass (impossible by definition) about how the ride would proceed on the following Friday.
What happened was beautifully documented in Ted White's documentary "We Are Traffic!" which you can see online . The police and Mayor Brown put up a sound system and stage and had the gall to welcome the riders to our own event. They were roundly booed. Brown, realizing that he had not managed to co-opt Critical Mass, decided to unleash the police. They were happy to oblige and a mini-riot took place in mid-Market where several cyclists were arbitrarily pushed to the ground, violently arrested, and their bikes impounded. Critical Mass had split into dozens of groups roaming the city's streets for hours, in what was probably one of the most chaotic evenings in Critical Mass history. The police could not get a handle on things, in spite of their license to repress, and it wasn't until very late that night that they corralled one of the mini-masses still riding, surrounding them in the financial district and arresting them all. The day after the Chronicle's false headline was "250 cyclists arrested!" The actual number was about 112, and most of them had been in the illegal roundup. Howard Besser, one of the arrestees, filed a suit against the police and won, and won a second time when the city appealed, and was awarded about $1,000 in damages. No one was ever convicted of any crimes that occured that night, because there had been no crimes!
The following month, August 1997, after a month of torrid bad press, online flame wars (much like you we still see on the SFGate) denouncing all bicyclists, and a remarkably one-sided representation of what had happened (no mention of Mayor Brown's land-swap shenanigans with the Transbay terminal property that was going on behind the scenes during the same summer), about 5,000 bicyclists showed up in defiant celebration at their own monthly gathering. This time, anticipating a very heavy-handed police presence, the plan was to follow the Good Soldier Schweik  approach, that is, ride to rule. Each cyclist would ride as if it were a motor vehicle, obeying all laws, stopping at every light and sign, signaling every turn, etc. That held for the first hour or so, and the traffic downtown was MUCH WORSE than it had ever been before. Thousands of cyclists filling the streets, obeying the traffic laws, turned out to be much more disruptive than following the safe and predictable method of Critical Mass that had evolved over time.
From that time forward , a kind of truce developed with the police. The ebb and flow of policing over the ensuing years has been unpredictable, going back and forth between angry belligerence and benign tolerance. Sometimes a bunch of bicycling cops joined us, sometimes there were hardly any police at all, and sometimes a whole bunch of motorcycle cops and paddy wagons would come. They've never made any mass arrests, but they do ticket riders on occasion, usually in a somewhat punitive fashion if they see someone they particularly want to inconvenience (it's generally for running red lights, or impeding traffic, or other normal Critical Mass behaviors). When they do, like a few months ago on Broadway coming east out of the tunnel, it led to a half hour traffic jam blocking the streets. Critical Mass riders don't always stop in solidarity with every rider who gets hassled by the cops, but when they do, it raises the costs to the city in terms of traffic blocked and the number of officers who gather to secure the area while a traffic infraction ticket is written.
It is a useful reminder to all that the best approach (usually the one taken by the cops when they're being reasonable) is to facilitate the ride moving continuously through the city until it's finished.
Police repression, when it comes, is part of a larger culture war  between those who think the American Way of Life is fundamentally about cars, business, and private property (almost always a strong bias of individual police) and the growing movement to shift into a new way of organizing our lives, based on ecological principles, reduced resource use, and a more convivial, publicly-oriented cityscape. Most of us riding in Critical Mass are not out to break the law or antagonize anyone, but we do feel strongly that we have to demonstrate firmly and directly a different way of life. To those of us committed to a life with a greater sense of conviviality and a commitment to a public sphere, the childish and antagonistic behavior that a few cyclists bring to the ride has been dismaying.
Unfortunately, the old xerocracy mostly died out (with the notable exception of the 10th anniversary ride in 2002--four different beautiful posters were made and put all around town, dozens of stickers and flyers were distributed at the ride, a book was published). Once or twice a year someone shows up with a flyer addressing the culture of the ride , or prepares a suggested route, but in general, cultural production, once so essential to the experience, went into hibernation. After more than a decade the transmission of the culture from oldtimers to newbies has broken down. People riding in Critical Mass these days might have been infants when we started it 18 years ago!
Sadly, some people show up because they believe all the media lies about this big anarchistic confrontational experience, though they are tiny in number. Still, when they behave badly they get an inordinate amount of attention, not just in the media when it deigns to address this ongoing cultural phenomenon, but weirdly, from other cyclists. There's a mentality that has been shaped by our profit-driven media: when it bleeds, it leads. I'm afraid all too many people on all sides of Critical Mass tend to fall into this same mental trap, focusing their attention on the tiny few who behave like jerks, rather than the overwhelming thousands (and not just here, but across the planet in over 300 cities worldwide) who manage things well, extend courtesy and kindness to bystanders, have joyful interchanges with people briefly stuck in buses and cars, and are greeted exuberantly from neighbors in their windows as we roll through central city neighborhoods.
Now the police seem to be threatening Critical Mass again, but to what end?
It's a small thing, lasting 2-3 hours a month, inconveniencing lots of people for a short time, but keeping an important cultural space open. In that space, a different kind of life is in gestation, where new friends and networks continually discover one another, where we experience radical direct democracy, rolling through the streets. And it is available to all comers. Historically it's been self-managed, and recently a new website  and discussion list have been started to remedy the fact that the culture hasn't been handed down well between generations of riders.
As for what could work, I'd suggest that Chief Gascon start by removing all motorized vehicles from accompanying the ride, send whatever police he deems necessary on bicycles, and reiterate that Critical Mass is a cultural fact of life in San Francisco. Anything else is likely to make things worse and cost the city a lot more money over the long haul.