Critical Mass rides have been perceived aa 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; 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." However, Critical Mass participants have insisted that these events should be viewed as "celebrations" and spontaneous gatherings, and not as protests or organized demonstrations. This stance allows Critical Mass to argue a legal position that its events can occur without advance notification of local police.
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 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 22 September (International Car Free Day) and 22 April (Earth Day). They attract tens of thousands of riders. The April 22, 2007 Budapest ride participation was generally estimated at 50,000 riders.
Article taken from here.