Critical Mass is a worldwide event that takes place in most major cities on the last Friday of every month. People gather on their bikes in a public place and ride through the city. Due to the sheer number of riders (sometimes in the thousands) the peloton stops traffic. Impromptu volunteers take turns corking to ensure rider saftey. The route is never pre-determined and there is no official leader. The lack of leadership prevents authorities from shutting down Critical Mass.

I’ve participated in the past two Critical Mass events in San Diego. The rides are generally easy to complete and last a little over 2 hours. Some in the group are very vocal, but overall the entire throng is well behaved. Motorists who become upset at Critical Mass should realize it takes less than 10 minutes for the peloton to pass.

Other related rides include the World Naked Bike Ride and a group of riders in LA called the Criminalz who have taken up the habit of riding bikes on I5 during rush hour.

Videos from the May and June 2008 Critical Mass:

May 2008 part 1:

May 2008 part 2:

June 2008:

Criminalz on I5 in LA: