Critical Mass

From Academic Kids

This article is about the public event of bicyclists taking over roadways. For the concept in nuclear physics, critical mass.
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San Francisco Critical Mass, 29th April, 2005.

Critical Mass is an event held typically on the last Friday of every month in cities around the world, where bicyclists and self-propelled people take to the streets en masse. Critical Mass has no leaders, and no goals other than to meet once every month and enjoy the security of riding, rolling and travelling through the city together. Critics, in particular the auto industry, have claimed that this is a deliberate attempt to obstruct traffic, and cause a disruption of normal city functions. Critical Mass does slow city traffic, but Critical Mass riders counter criticisms that they are causing congestion saying "We aren't blocking traffic, we are traffic."


History and organization of the rides

Since rides started in San Francisco in 1992 they have spread to more than 325 cities around the world. The San Francisco Critical Mass—which traditionally starts at Justin Herman Plaza, at the end of Market Street, on the Embarcadero—has had an undeniable effect in exhorting local government and city planners to consider cyclists' needs and facilities in urban planning.

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Melbourne Critical Massers are controlled by the police, with limited success

The term "critical mass" was adopted from an observation made by American Human Powered Vehicle and pedicab designer George Bliss while visiting China. He noted that traffic, both motorists and bicyclists, in China had an understood method of negotiating unsignalled intersections. Traffic would "bunch up" at these intersections until the back log reached a "critical mass" at which point that mass would move through the intersection. This description was related in the Ted White documentary Return of the Scorcher (1992) and subsequently adopted by the Critical Mass movement.

Critical Mass differs from many other social movements in its rhizomal (rather than arboreal) structure. Critical Mass claims to be an "organized coincidence", with no leader, no organizers, and no membership. For example, the term xerocracy was coined to describe the process for how the route for a Critical Mass is decided: Anyone who has an opinion makes their own map, and distributes it to the cyclists participating in the Mass. Some rides are decided "on the fly" by those at the front of the pack. Other rides are decided on the day of the ride before-hand by a popular vote of suggested routes. Still other rides decide the route by consensus. These methods free up the movement from the overhead costs involved in a hierarchical organisation: no meetings, no structure, no internal politics, and so on. In order for it to exist, all that has to happen is that enough people know about it and turn up on the day to create a 'critical mass' of riders large enough to safely occupy a piece of road to the exclusion of motorized road users.

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Cyclists in Critical Mass ride through New York City's famous Times Square on July 30, 2004

Some Critical Mass riders carry out an illegal action known as "corking", which involves blocking cross traffic so that the riders can freely proceed through red lights. The mass always tries to accommodate and yield for emergency vehicles by splitting through the center when cyclists move over to the left and right sides of the road. Critics argue that this practice of corking is contrary to its claim that "we are traffic", since ordinary traffic (including bicycle traffic that does not participate in Critical Mass) does not have the privilege of being able to ignore traffic lights, however riders counter that keeping the ride as a single mass improves the safety of the riders and minimizes the disruption to other traffic. Sometimes, this act of has translated into hostility between motorists and riders, which has even erupted into violence during some critical mass rides. However, most rides pass off peaceably with little incident.

After the RNC (2004 Republican National Convention) coincided with the August 2004 NYC Critical Mass, many court cases resulted regarding the legality of the ride, whether police have the right to arrest cyclists and seize their bicycles, and whether the 'event' needs a permit. In December of 2004, a federal judge threw out the NYC's injunction against Critical Mass as a "political event." [1] ( On March 23, 2005, NYC filed a lawsuit, seeking to prevent TIME'S UP! from promoting or advertising Critical Mass rides. The lawsuit also stated TIME'S UP! and the general public could not participate in riding or gathering at the Critical Mass bike ride, claiming a permit was required. [2] ( [3] (

Current active rides

Unless otherwise stated, rides are held on the last Friday of every month at 5:30pm.




  • Budapest [5] (, at Heroes' Square.


  • Turin [6] (
  • Rome [7] (


  • Warsaw [8] (, at Zamkowy Place (6 pm)


  • Moscow [9] ( (in Russian), rides are held on the last Saturday of every month at 01.00pm starting from Turgenevskaya Square.

United Kingdom

United States

See also

External links

it:Massa critica (di biciclette) lt:Kritinė Masė pl:Masa Krytyczna


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