More bikers = increased safety.

From the Atlantic.

http://business.theatlantic.com/2009/08/why_bike-sharing_programs_are_really_good_ideas.php

The number of reported accidents goes down as the ridership increases (ummm... stating the obvious much? I apparently wrote this for those of you can't read graphs ;) .

NYC seems to have improved their infrastructure significantly over the last few years, which may also be a contributing factor, but internationally, it seems to be working two fold; increasing ridership and safety. Correlationally, at least...