Bicyclist fatalities report (not detailed enough to be useful)
The problem with the report, Spotlight on Highway Safety: Bicyclist Safety, from the Governors Highway Safety Association, which found a 16% increase in bicyclist fatalities from 2010 to 2012, is that it doesn't distinguish between urban, suburban, and rural spatial conditions.
Data at the state-level doesn't say enough to be actionable, although the report does say that since the 1970s, urban bicyclist fatalities have increased from 50% to 69% of the total.
For example, bicycle sharing could be a factor in the rise, although according to Reuters ("After 23 million rides, no deaths in U.S. bike share programs") there haven't been fatalities associated with the introduction of bicycle sharing in the U.S.
For example, it would be very interesting to calibrate bicycle accidents and deaths against the recent Census report, Modes Less Traveled—Bicycling and Walking to Work in the United States: 2008–2012, that looks at the rise of bicycle commuting in the 50 largest metropolitan areas.
By looking at the data at a more granular level, it's possible to make more focused recommendations that can have some impact.
As an example, the Boston Globe recently did a study, "Bike fatalities rise in Greater Boston’s suburbs," of all bicyclist accidents across the state, by town or township.
For what it's worth, while I do think it's likely that as bicycling for transportation increases, as a percentage of rides accidents will fall even if there is an increase in accidents/deaths, I can understand there being an increase in accidents and deaths because most motor vehicle operators have limited experience driving around bicyclists, and/or in center cities, and a preponderance of regular bicyclists are in center city locales.