National Travel Survey, conducted annually. Analysis from six years of data. “Questions yesterday's trip stages (to build trip and journey data), respondents, respondents' household members, and household cars”. Factoid: 15% of Danes' cycling trips are “with company”.

Crash Portal (another project of mine) - This site links to bike crash mapping efforts, starting in Chicago but expanding to include the projects in other cities. So far, London is the only international city.

FARS Encyclopedia - The Fatality Analysis Reporting System managed by the National Highway Traffic Safety Administration (NHTSA).

2012 bicycle crashes in Chicago

2011 bike crashes in Chicago

Chicago bike crash data

Bicycling related data for Chicago