Originally Posted by slate
More bikes create peer pressure for bikers to follow the law. (In Copenhagen, for example, you'll see long lines of bikes stopped at traffic lights.)
I too think a maturation of riding compliance with the law and better law abiding behavior comes from a critical mass of bicyclists on the roads.
It's observable behavior by the commuter peloton at major intersections in Seattle and Portland and San Francisco every morning. Likely so in any city there is a high rider share.