Critical Mass

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Critical Mass, San Francisco, April 29, 2005

San Francisco Critical Mass, April 29, 2005.

Cyklojizda Prague 4517

Critical Mass on the bridge over Nusle, Czech Republic, September 22, 2007

Critical Mass is a bicycling event typically held on the last Friday of every month in over 300 cities around the world.[1] While the ride was originally founded in 1992 with the idea of drawing attention to how unfriendly the city was to bicyclists,[2] the leaderless structure of Critical Mass makes it impossible to assign it any one specific goal. In fact, the purpose of Critical Mass is not formalized beyond the direct action of meeting at a set location and time and traveling as a group through city or town streets.



San Francisco Broadway Tunnel 29 September 2006

Critical Mass rides have been perceived as protest activities. A 2006 New Yorker magazine article described Critical Mass' activity in New York City as "monthly political-protest rides", and characterized Critical Mass as a part of a social movement;[3] and the UK e-zine Urban75, which advertises as well as publishes photographs of the Critical Mass event in London, describes this as "the monthly protest by cyclists reclaiming the streets of London."[4] However, Critical Mass participants have insisted that these events should be viewed as "celebrations" and spontaneous gatherings, and not as protests or organized demonstrations.[5][6] This stance allows Critical Mass to argue a legal position that its events can occur without advance notification of local police.[7][8]

Critical Mass rides vary greatly in many respects, including frequency and number of participants. For example, many small cities have monthly Critical Mass rides with fewer than twenty riders which offer safety in numbers[9] to cyclists in those locales, while on the opposite extreme, in what have been the largest events using the name Critical Mass, cyclists in Budapest, Hungary hold only two rides each year on April 22 (Earth Day) and September 22 (International Car Free Day). The 'Budapest style' attracts tens of thousands of riders.[10] The April 20, 2008 Budapest ride participation was generally estimated at 80,000 riders.[11][12]


Critical Mass-like bike tours with hundreds of participants took place in Stockholm, Sweden in the early 1970s [13]. But the first ride within the present wave took place on Friday, September 25, 1992 at 6 p.m. in San Francisco. At that time, the event was known as Commute Clot and was composed of a couple of dozen cyclists who had received flyers on Market Street.[2]

Shortly after this, some participants in that ride went to a local bicycle shop for a screening of Ted White's documentary Return of the Scorcher, about bike culture overseas. In that film, American human powered vehicle and pedicabs designer George Bliss noted that, in China, both motorists and bicyclists had an understood method of negotiating intersections without signals. Traffic would "bunch up" at these intersections until the backlog reached a "critical mass", at which point that mass would move through the intersection. That term from the movie was applied to the ride,[14] and the name caught on, replacing "Commute Clot" by the time of the second event.[2]

By the time of the fourth ride, the number of cyclists had increased to around 100 and participation continued to grow dramatically, reaching about 1,000 riders, on average.[2]

The name was soon adopted as a generic label by participants in similar but independent mass rides that were either initiated in various locations around the world at around the same time, or had already existed before 1992 under other names. It is estimated that there are Critical Mass-type rides in more than 325 cities to date. The term "masser" is sometimes applied to frequent participants.[15]


Critical Mass differs from many other social movements in its rhizomal (rather than hierarchical) structure. Critical Mass is sometimes called an "organized coincidence", with no leadership or membership. The routes of some rides are decided spontaneously by whomever is currently at the front of the ride, others are decided prior to the ride by a popular vote of suggested routes often drawn up on photocopied flyers. The term xerocracy was coined to describe a process by which the route for a Critical Mass can be decided: anyone who has an opinion makes their own map and distributes it to the cyclists participating in the Mass. Still other rides decide the route by consensus. The "disorganized" nature of the event allows it to largely escape clampdown by authorities who may view the rides as forms of parades or organized protest. Additionally, the movement is free from the structural costs associated with a centralized, hierarchical organization. In order for the event to function, the only requirement is a sufficient turn-out to create a "critical mass" of riders dense enough to occupy a piece of road to the exclusion of drivers of motorized vehicles, pedestrians, and other road users. Authorities in New York, California and Oregon have expressed concern with the difficulty of coordinating with the riders, due to the lack of leadership.[16][17][18]

The city of New Haven includes the event in its city-published Green Map.[19]



Detail from the November 20, 1992 flyer by Joel Pomerantz which introduced the concept of corking.

Because Critical Mass takes place without an official route or sanction, participants in some cities have sometimes practiced a tactic known as "corking" in order to maintain the cohesion of the group. This tactic consists of a few riders blocking traffic from side roads so that the mass can freely proceed through red lights without interruption. Corking allows the mass to engage in a variety of activities, such as forming a cyclone, lifting their bikes in a tradition known as a "Bike Lift" (in Chicago this is referred to as a Chicago hold-up), or to perform a "die-in" where riders lie on the ground with their bikes to symbolise cyclist deaths and injuries caused by automobiles, very popular in Montreal. The 'Corks' sometimes take advantage of their time corking to distribute flyers.

Critics argue that the practice of corking roads in order to pass through red lights as a group is contrary to Critical Mass' claim that "we are traffic", since ordinary traffic (including bicycle traffic) does not usually have the right to go through intersections once the traffic signal has changed to red. Corking has sometimes led to hostility between motorists and riders, even erupting into violence and arrests of motorists and cyclists alike during Critical Mass rides.[20]

Reaction and controversy[]

General impact[]

The name of the event has been subjected to word play in many contexts, ranging from advertising campaigns for commercial products to numerous other public events.[21]

The Rand Corporation produced a white paper entitled "What Next for Networks and Netwars?" analyzing the tactics of the ride, as part of an evaluation of decentralized decision-making for potential military battlefield use.[22] The ride has generated books,[23] documentary films,[24] murals,[25] and other secondary artifacts.

Conflicts involving Critical Mass[]

Main article: Conflicts involving Critical Mass (English Wikipedia article)

Critical Mass rides have generated considerable controversy and public opposition.[26] Critics claim that Critical Mass is a deliberate attempt to obstruct traffic and disrupt normal city functions, asserting that individuals taking part refuse to obey traffic laws.[27] Altercations with police and motorists have occurred. Although uncommon, protesters are sometimes present at Critical Mass events to oppose the group's methods.

Reaction of other cyclists[]

Some bicycling advocacy groups have expressed concern that the "subversive" nature of Critical Mass and altercations with motorists could weaken public support for bicyclists.[17] Though it does not condone incidents of violence and rudeness, the San Francisco Bicycle Coalition credits Critical Mass with spotlighting bicycle issues and aiding their efforts in advocating for cyclists.[2]

Critical Manners[]

In San Francisco, an event known as "Critical Manners" was created as a response to Critical Mass. Critical Manners rides through the city on the second Friday of the month, with riders encouraged to obey all traffic laws such as stopping at red lights and signaling.[28][29][30] Tucson, Arizona holds the Tuesday Night Community Bike Ride as their alternative to Critical Mass. The weekly ride encourages bicycle commuting and motor vehicle awareness in a peaceful and friendly way.[31]

In 2007 there were conversations about starting Critical Manners in Portland, Oregon.[32] According to the Critical Mass book, edited by Chris Carlsson, a similar project known as Courteous Mass is described as "an alternative to Critical Mass." Courteous Mass was discontinued in late 2002 due to "lack of interest"[33]

An alternative ride named RideCivil formed in Seattle, Washington in late 2007.[34] Rides are on the 2nd Friday of every month, and focus on encouraging civility between motorists, pedestrians and cyclists.[35]

Other movements[]

The Critical Mass rides have inspired a number of other bicycle movements, that range from political movements to the "Critical Tits" ride during the yearly Burning Man festival.[36] In Chicago, a movement has grown out of the Critical Mass community to promote winter cycling via the bikewinter campaign.[37] The extensive news coverage of San Francisco's July 1997 ride spawned an international celebration of bicycling, called Bike Summer.[38] Critical Sass is an all female version of the ride in Baton Rouge, Louisiana, that takes place the second Friday of every month. Examples of Critical Mass rides for political movements includes the Free Tibet Rides (May 2008): Free Tibet Critical Mass in Columbia, MO, "Tibetan Freedom Bike Rally" in San Francisco (Aug 2008), and in "Bike Ride for Tibet" in London (Aug 2008).[39]


  1. Richard Madden (15 December 2003), London: How cyclists around the world put a spoke in the motorist's wheel, The Daily Telegraph, <> 
  2. 2.0 2.1 2.2 2.3 2.4 Garofoli, Joe. "Critical Mass turns 10", San Francisco Chronicle, September 28, 2002. Retrieved on 2007-07-02. 
  3. Mcgrath, Ben. "Holy Rollers", November 13, 2006. Archived from the original on September 4, 2012. 
  4. Critical Mass London. Urban75 (2006).
  5. Pittsburgh Critical Mass.
  6. Critical Mass: Over 260 Arrested in First Major Protest of RNC. Democracy Now! (August 30, 2004).
  7. Seaton, Matt. "Critical crackdown", The Guardian, October 26, 2005. 
  8. Rosi-Kessel, Adam (August 24, 2004). [*BCM* Hong Kong Critical Mass News].
  9. Gaffney, Dan (September 3, 2008). A virtuous cycle: safety in numbers for riders says research. Retrieved on 2008-10-03.
  10. Budapest Sun Online - Daily news coverage, information on Hungary 's upcoming cultural events, cinema listings, restaurant and music reviews - A critical mass critique
  11. MTI - Minden eddiginél többen vettek részt a Critical Mass felvonuláson (Hungarian)
  12. Critical Mass wheels away - Budapest Sun Online
  13. [1]
  14. Pomerantz, Joel (2002), “A Critical Mass Cultural Glossary”, in Carlsson, Chris, Critical Mass: Bicycling's Defiant Celebration, Edinburgh, Scotland: AK Press, 1-902593-59-6, <> 
  15. FAQ Chicago Critical Mass
  16. Susan Palmer. "Rolling protests hit bump", The Register-Guard (Eugene, OR), May 20, 2006. 
  17. 17.0 17.1 Martha T. Moore. "Big pack of bikes piques police", USA Today, November 15, 2004. 
  18. MetroActive News & Issues Critical Mass
  19. Welcome to the City of New Haven City Plan Department
  20. Gutierrez, Scott. "2 bicyclists arrested at Critical Mass get out of jail", Seattle Post-Intelligencer, July 3, 2006. 
  21. Ignition Northwest
  23. Critical Mass: Bicycling's Defiant Celebration :: AK Press
  24. We Are Traffic! DVD :: AK Press
  25. The Duboce Bikeway Mural
  26. Michael Cabanatuan, Jaxon Van Derbeken and Cecilia M. Vega. "Clash reignites road wars:Skirmish between driver, Critical Mass participants triggers another round of debate about monthly ride", San Francisco Chronicle, April 5, 2007. Archived from the original on December 20, 2007. 
  27. Gord MacFarlane. "Critical Mass protesters too critical", Winnipeg Sun, August 7, 2006. 
  28. Steve, Rubenstein. "Critical Manners takes a stand for sharing, harmony, red lights.", San Francisco Chronicle, April 14, 2007. Retrieved on 2007-07-02. 
  29. Critical Manners Ride SF Google Groups
  30. Steve Rubenstein. "Critical Manners ride starts at 6 p.m.", April 13, 2007. Retrieved on 2008-02-23. 
  31. Herreras, Mari (November 8, 2007). Tucson on Two Wheels. Tucson Weekly. Retrieved on 10 December 2008.
  32. Would Critical Manners Catch On In Portland?
  33. (Austin) Rides & Events
  34. Critical Man-nerds ride report. Bike Hugger (October 16, 2007). Retrieved on 2009-02-25.
  35. Seattle Ride Civil website.
  36. Critical Tits Party FAQ. Retrieved on 2008-02-22.
  38. BikeSummer 2006: History
  39. Free Tibet protesters hit the streets on bikes. Retrieved on 2008-11-26.

External links[]


This article or parts of this article are based on the Wikipedia article Critical_Mass (Version from March 04, 2009) licensed under the terms of the GNU Free Documentation License, version 1.2 or later. A list of the authors can be found here: [2]. You can help to improve the article.