As FABB pointed out, MWCOG has updated the 2010 Bicycle and Pedestrian Plan for the National Capital Region.
Fifty-three projects from the 2010 Bicycle and Pedestrian Plan have been completed, including the 11th Street Bridge Trail and several protected or buffered bike lanes. The region added 52 miles of multiuse path and 45 miles of bike lanes. This does not include many projects that have been partially completed, or any privately provided facilities, or projects such as sidewalk retrofits that were too small to be included in a regional plan.
The Washington region has become a national leader in innovative policies and designs, especially bike sharing (public self-service bicycle rental). In September 2010, the District of Columbia and Arlington County launched a regional bike sharing system, Capital Bikeshare, which has since expanded to over 2500 bicycles at 300 stations in DC, Arlington, Alexandria, and Montgomery County.
The document is sort of a clearing house for all the current data on biking and walking including counts, planning, safety metrics, Bike to school day participation etc.. Things like this chart.
It's a good read for anyone who wants to know all the facts about regional cycling past, present and future; but there isn't really anything new in it.