a recent (March 2011) article from the journal of environmental practice with a scholarly analysis of bike collision injury rates in a dozen or so california cities, with a well referenced and scholarly overview of the safety in numbers traffic concept.
Good reading.
its an affirmation that the amalgamation of road design and traffic conditions amenable to bicyclists is correlated to safer cities for all road users. A good paper to bring to your city council.
bike friendly cities safer for all road users
Originally Posted by journal of environmental practice, Mar 2011
......We do not yet have the data to disentangle the “safety in numbers”
concept from the street and community design effects, but
our results strongly suggest that safety benefits for all road
users can be derived from an amalgamation of the steps
taken to attract more bicyclists. While it is also important
to point out that we do not have enough information to
claim any causal relationship with this research, the trends
do suggest that the issues of “safety in numbers” and street
design are interrelated.