How to make a CRITICAL MASS
Lessons and Ideas from the San Francisco Experience

Hey! Get out of our way!
Illustration by Jim Swanson


"What’s this all about?" ask amused and bemused pedestrians on Market Street as hundreds of noisy, high-spirited bicyclists ride past, yelling and ringing their bells. There are a wide variety of answers: "It’s about banning cars." "It’s about having fun in the street." "It’s about a more social way of life." "It’s about asserting our right to the road". "It’s about solidarity." Critical Mass is many things to many people, and while many concepts expressed may evoke memories of past political protests, Critical Mass is foremost a celebration, not a protest.

Critical Mass got started in September 1992 in San Francisco as a way to bring these various populations together in a festive re-claiming of public space. The idea was initially conceived by one person, who bounced the idea off other cyclists. San Francisco’s prominent bicycle messenger community was enlisted primarily through word of mouth, while commuters were reached by someone standing in the middle of the financial district passing out flyers.

Beginning rather under a less catchy name—the Commute Clot—the ride drew an initial crowd of 60 cyclists, and these numbers doubled for several months following. Critical Mass has continued and grown in San Francisco, drawing about 700+ from month to month, with an October 1993 high of 1000+, but it has spread to other cities as well. With independent rides springing up all over the place (list of cities), Critical Mass has begun to take on the character of a large scale, decentralized grassroots movement!

Ultimately, Critical Mass is just a bunch of cyclists riding around together, going from one point to another. (Someone coined the descriptive phrase "organized coincidence.") But the incredible thing is that, in attempting this simple task, so many important and interesting questions come up. Why is there so little open space in our cities where people can relax and interact, free from the incessant buying and selling of ordinary life? Why are people compelled to organize their lives around having a car? What would an alternative future look like?

In writing this pamphlet, we have not set out to answer these questions. Instead, we are using our familiarity with only one of the many Critical Mass rides (San Francisco’s) to help accelerate the spread of Critical Mass to other cities, and share ideas tactics, solutions, etc. We hope that a small, inexpensive and easily reproduced pamphlet would go a long way toward providing interested parties with the information and materials they need to set up their own ride.

It is important to emphasize, however, that no two rides will be identical, and while Critical Mass may be a common approach to a common problem, different contexts will produce different dynamics, pressures, etc. This pamphlet, then, is in no way intended as an "official blueprint" or strict set of guidelines set forth by some all-knowing committee. Rather, it is simply the brainchild of a small handful of Critical Mass enthusiasts in the Bay Area, and it will inevitably reflect our experiences, prejudices and beliefs.

Pre-ride planning

It should be relatively easy to set up a Critical Mass ride. Whether they are commuters, couriers, or ride just for the fun of it, every city has a population of bicyclists that are marginalized and threatened by the current transportation system. Perhaps more importantly, these groups are just the tip of the iceberg. Poor air quality, environmental degradation and the general decay of living conditions due to over-reliance on motorized traffic in urban areas are felt by everyone. There is a potential mass base for change in all these scattered, isolated groups, and a Critical Mass ride can serve as a rallying point to bring them together.


In San Francisco the organization of the event has been as much a part of its success as anything else. Organizational politics, with its official leaders, demands, etc., has been eschewed in favor of a more decentralized system. There is no one in charge. Ideas are spread, routes shared, and consensus sought through the ubiquitous copy machines on every job or at copy shops in every neighborhood—a "Xerocracy", in which anyone is free to make copies of their ideas and pass them around. Leaflets, flyers, stickers and ‘zines all circulate madly both before, during and after the ride, rendering leaders unnecessary by ensuring that strategies and tactics are understood by as many people as posssible.

Xerocracy promotes freedom and undercuts hierarchy because the mission is not set by a few in charge, but rather is broadly defined by its participants. The ride is not narrowly seen as an attempt to lobby for more bike lanes (although that goal exists) or to protest this or that aspect of the social order (although such sentiments are often expressed). Rather, each person is free to invent his or her own reasons for participating and is also free to share those ideas with others. Some people are there to promote human powered transportation as a viable alternative, others seek the respect of motorists and city planners and some take part simply because they like riding bikes and feeling a sense of community with all the other cyclists on the Critical Mass ride.

This "organic system" doesn’t lead to chaos, but rather a festive, celebratory atmosphere. Great pains have been taken to avoid the common pitfalls of other movements, with much Xerocratic space being devoted to arguments against moralizing attacks on motorists and other unproductive tendencies. By presenting bicycling as a fun, positive alternative to the dreary destructiveness of car culture, Critical Mass has gained immeasurably.


Getting the word out is the first step. Flyers are a quick, cheap way to reach a large number of people. With a few friends and a copy machine, you can have your area saturated with Critical Mass announcements within a few days. However, the public walls of most cities have already been plastered with so many announcements that alternative strategies are useful.

• Thin strips of xeroxed flyers can be attached to bicycles around town.

• Small stickers can be put on anything bicyclists lock their bikes to.

• Bicycle stores and bike-friendly businesses can be asked to put flyers in their windows.

• Word of mouth, announcements by friendly local radio DJs,on stage in clubs, etc.


The preliminary steps to setting up a ride are fairly straight forward: pick a time, place and route. Beginning the ride in some downtown area is obviously a good choice, since so many bicyclists and commuters are already there. A well-known public area, easily accesible to most bicyclists, where large numbers of people can congregate before the ride is perfect. (In San Francisco, Critical Mass leaves from a plaza adjacent to the financial district, which is conveniently located at the foot of the main traffic corridor.)

Choosing a time is even easier: you want to meet in the early evening, say 5:30, both in order to accommodate bicycle commuters who are on the streets anyway, and to gain visibility by making sure Critical Mass is part of the rush hour traffic. Having Critical Mass fall on a Friday marks it as the beginning of the weekend, and contributes to the celebratory feel of the ride. And what better Friday for the event to take place than the last Friday of the month? If Critical Mass continues to spread, the day may come when, on the last Friday of the month, the sun is always setting on a Critical Mass ride!

It is important that the meeting time and place remain constant, so that it is as easy for people to take part on a regular basis, and more people can join in as the ride becomes a regular event.


Picking a safe, entertaining route is integral to keeping Critical Mass novel and fun. There are several things to consider when planning a route:


• Bicyclists of varying skills will be taking part; planning a ride with lots of difficult hills or a very long distance is not a good idea.

• The streets chosen should be large enough to accommodate large numbers of cyclists. (One way streets are especially good.)

• Keep it simple. A complicated route that veers all over the place might look fun on paper, but will prove to be unworkable on the ride. People need to be able to read and easily memorize the route, so they know where they’re going and what the ride is doing.


• Varying the route from month to month makes each ride a bit of an adventure, and reaches a wider spectrum of people.

• The mood of the ride is influenced by the area cycled through. A ride through a downtown area, where whoops and hollers can echo off tall buildings, and there is a population of motorists and bystanders to interact with, will create a more festive mood than a ride through an industrial or suburban area. The latter two tend to quiet down the ride, which could be used to vary the mood. It’s up to you.

• Have an end point, such as a park or bar, where there’s the possibility for cyclists to socialize after the ride.

XEROCRATIC AESTHETICS: If you want to communicate, make it easy to read!

Make sure the fliers passed out to participants are readable and tell people what they need to know about the ride. For instance, if there is a tricky intersection, or dangerous train tracks on the route, point it out on the map. Doing the route flyer on a computer can make things easier (if you’re computer literate, and has the advantage of being easy to read and reproduce). The route sheet can also double as an informational bulletin/newsletter, with troubleshooting ideas, news from the last ride, and ideas for future rides.

As the San Francisco Critical Mass grew beyond the point where a single bicyclist could see both front and tail of the ride (about 300+), a xerocratic publication, Critical Mass Missives, started to appear. It contains happenings on the previous ride, news of other Mass’s around the world and discusses problems within or concerning the ride.


When bicyclists take to the streets en masse, there will be a certain percentage of motorists who will not be amused. These motorists—a minority, to be sure—will have a hard time seeing a group of bicyclists as legitimate traffic, and may insist on forcing their way through the crowd. The interference of these frustrated individuals, trapped as they are in their cars, are a CONSTANT problem for Critical Mass. Tactics have to be developed, understood, and implemented by as many people as possible in order to ensure that this problem does not become too much of a drag on an otherwise fun and good-natured ride. Here are the ones we’ve found work.


Think of Critical Mass as a density. It works by forming a mass of bicyclists so dense and tight that it simply displaces cars. Anytime the ride begins to spread too thin, with areas large enough for a car to drive into, you have a potential trouble spot developing.

The simplest and easiest way to deal with this problem is to encourage people to be aware of what’s going on around them, and to act when they see things go awry. If a gap large enough for a car develops, someone needs to ride into it and call over a friend. If the head of the ride moves too fast and the Mass becomes too thin, someone in front needs to call out for people to slow down, and for the ride to regroup. The same goes for those at the tail of the ride, who may be riding so slow that the ride, again, spreads too thin. Diagrams on the route sheet pointing out trouble areas and regrouping points are a great way to bring all this across.

Density is vital in ensuring safety and a solid image of bicycling as practical, safe and fun for the ride’s participants. When Critical Mass is still passing through an intersection after the light has turned red, in rush hour traffic, it is important to justify the long wait for cross traffic by maintaining a steady mass of bicyclists riding through the intersection.


Corks are the diplomats of the ride. Their title comes from their function. Here’s how they work: one or two bicyclists block each lane of oncoming traffic as the ride goes through an intersection, making sure that even if a gap large enough for a car to drive through should develop, cars are stopped where they are. This tactic is especially effective if the cork takes a friendly, non-antagonistic stance with motorists, even holding up signs that say "thanks for waiting" and "honk if you like bikes!" Corks need to protect the rear of the ride, too, from cars turning into it. Of course, no one needs to be officially designated as a cork, and people will largely take on this role of their own initiative.

Red Lights

Should Critical Mass obey the same traffic laws that motorized traffic follows? Yes and no. For the most part, traffic laws were made for cars, as anyone who routinely bicycles through stop signs can attest, and they certainly weren’t written with large groups of bicyclists in mind. So the answer to this question is obvious: Critical Mass should bend or ignore existing traffic laws where the group’s safety and effectiveness will be served, and follow the law where it serves our interests and needs.

Red lights are a perfect example of this principle. When the head of the ride reaches a red light, it only makes sense to stop. This way, a) no one endangers themselves by riding into oncoming traffic, b) we allow motorists the simple courtesy of their right of way, and c) we give ourselves an opportunity to stop, regroup and form a solid Mass. But if, as Critical Mass passes through an intersection, the light changes, it does not make sense to break into two groups, and the ride should just continue through the intersection, shielded from the waiting cars by corks.

Breaking Mass

When the Mass thins out too much to justify holding an intersection through a red light, it can be useful for someone to yell out "BREAK MASS!" The first section of Critical Mass would continue through the intersection and the second part would wait for the light to turn green. If all goes well, the two groups will be reunited at the next light. This tactic is most often used when the Mass gets larger and less cohesive.


As the ride goes along, people on the street, waiting at bus stops or sitting in their cars will want to know what’s going on. You won’t be able to stop and talk with all of them, and you’d be hard pressed to fit it all into one sentence even if you could. So for anyone that is curious, it really helps to have a small flyer made out that lets people know what Critical Mass is, why we feel this action is necessary, and that invites them to the next ride.

These flyers can be made to fit three to an 8 1/2 sheet of paper so that they’re inexpensive and can fit well in your back pocket. Pass them out at the beginning of the ride, make sure that anyone who is interested has a stack to give out, and watch as they get passed out to hundreds of people who otherwise would have never heard of Critical Mass!

Those who hand out flyers along the route are the real diplomats of the ride. Often the face-to-face contact by these cyclists and occasional rollerbladers have been especially helpful in diffusing tense situations arising from an angry car driver who has been made to wait. A cyclist will roll up to these frustrated commuters and explain the ride while handing them a flyer. This shows people you’ve thought of them a bit, and it buys you some time as they digest the tract while the ride proceeds.

Like the corks, flyer distributors lend an air of self-control to the ride for motorists and pedestrians. Corking and flyer distribution is usually done on an ad-hoc basis, as needed, by cyclists who decide spontaneously to fill those gaps.


The above planning is the skeleton of what the Mass needs in order to be as enjoyable and carefree as it is. However, other issues arise as soon as bicyclists, hundreds of bicyclists, hit the streets. Should Critical Mass obey the same traffic laws that motorized traffic follows? For the most part, traffic laws were made for cars, as anyone who routinely bicycles through stop signs can attest, and they certainly weren’t written with large groups of bicyclists in mind. So the answer to this question is Critical Mass should bend or ignore existing traffic laws where the group’s safety and effectiveness will be served.

Traffic laws vary from state to state and city to city. Find out what the Vehicle Code says about bikes in your area. Know your rights; in California bicyclists "enjoy" all the rights and responsibilities of motor vehicles. Knowing the truth about what is in the book and being able to correct those who quote it wrongly empowers the riders on Critical Mass. You can obtain a traffic rules and regulations book at a Department of Motor Vehicles office.


What kind of approach do we take toward people who choose to drive, or who happen to be stuck in cars, maybe for business, when the ride passes? Just as important as devising strategies to deal with hostile motorists is the need to deal with those in the ride who may provoke them.

For some bicyclists, Critical Mass is an opportunity to berate motorists, now that WE own the road for once. Our society’s over-reliance on motorized traffic is a massive and overwhelming social problem, and it won’t be changed through the use of bitchy, ineffective tactics by a small minority of pissed-off bicyclists. But a movement for change based on a reclaiming of public space and the building of human community, open to people from across the social and political spectrum, could contribute to a deeper and more fundamental change in the way our society operates.


One of the important things to realize is that the Mass will tend to follow whoever is is front, whether they have a clear idea of where they’re going or not. "Vanguard" types, frustrated that their self-destructive antics are not put up with in the middle of the ride, will generally sprint ahead of the ride, go through red lights when it isn’t necessary, and try to block as much traffic as possible. Or, they may decide to lead the ride off the agreed route.

What happens then is that the head of the ride goes too fast, the ride spreads out, cars get in the middle of the ride, no one has any idea what is going on, dangerous situations occur pretty rapidly, and your Critical Mass becomes a Critical Mess.

The way to counter this is to get two or three friends at the head of the ride who have some idea of what the route is and, more importantly, are committed to staying in a group. If you all stick together as a clump, you can influence the course of the ride by riding slowly, speaking out where neccessary, and trying to keep everyone together. If you do this, you have to be prepared to take a certain amount of shit from people who may see you as someone imposing your ideas on everyone else. But speaking your mind and actively asserting your initiative is not akin to being authoritarian—in fact, it’s the essence of democracy.


Snails are a group of antagonistic bicyclists who poke slowly behind the rest of the mass. This dawdling causes the mass to thin out and anger car drivers who are waiting for the ride to progress through the intersection or who are behind the mass and impatient for the mass get moving.

Again, make your opinion known and be comfortable with that type of interaction. Remember, these people are not out to have the best time for the greatest numbers. They are selfishly antagonizing motorists and destroying any positive association that the drivers once might have had when the rest of the jovial mass passed them.


Public demonstrations tend to make the government look bad, since they vividly show that the government does not always represent or have the support of the people. Naturally, the police are concerned about popular demonstrations, and they generally take one of two approaches: either they attack the demonstration—exposing the force on which this society is based—or they attempt to portray themselves as the demonstration’s sponsors and diligent protectors.

With the Bay Area Critical Mass rides, they have generally taken the second, paternalistic approach, allowing the ride to take place, blocking traffic for us and making sure their presence is felt as an "escort". On one occassion they even went so far as to announce over a bullhorn before the ride "Welcome to this event!"—an outsider might have surmised that the whole thing was planned and executed by the police themselves!

When police begin to arrest people or hassle riders, they are trying to provoke a confrontation which will justify a repressive crackdown—a confrontation in which their victory is almost guaranteed. It is important not to take them up on the offer. When the police demand that the ride move into the right lane, do it. Then, when the coast is clear, go back. After a few more attempts to control the ride, the police usually give in and realize, short of arresting everyone, there’s little they can do except ride along and actually act like the public servants they professed to be in the beginning.

The best strategy is to avoid breaking any laws you don’t have to, try to reason with those individuals on the ride who display a tendency to get out of hand and don’t give the police an excuse to stop your ride or bust anybody. Be up front and above board about the ride. After all, we’re just riding home together in an organized coincidence, so give the cops the route sheet if they want one.

As much as they may try to own or control the ride, Critical Mass is a popular movement that operates independently of government regulations, and as such, we don’t have any business with the police (although they may have business with us). Within the anti-authoritarian culture of the bicyclist milieu, refusing the arbitrary commands of the police might make sense. But the best approach to the police presence at Critical Mass is not to engage in some pathetic, losing confrontation, or embrace them as our saviors and protectors. Rather, we should ignore them and get on with the business of trying to build a Mass.

This booklet was printed in early 1994 after being produced by an ad-hoc collective consisting of Chris Carlsson, Jim Swanson, Hugh D'Andrade, Kash, Nigel French, Beth Verdekal, Kathy Roberts, and several others...

Return to Index