Bike Trains - another potential way to promote cycling?

This article at the Guardian's (a British newspaper) bike blog describes bike trains. Bike trains are groups of riders who assertively ride busy urban streets in order to remind people that cyclists may be found on every street, and to reclaim road space. By moving in larger numbers (the average British bike train consists of eight riders), safety or at least visibility is improved relative to a single rider.

Do bike trains exist within the state? They could potentially also be organized to facilitate bike commutes on busier streets.