The black line is the total number of accidents for the Commonwealth (plotted against the right Y axis). The blue line is Arlington. During this time, the number of cyclists on the road has gone up significantly. See Arlington Data.
For Arlington, in terms of raw number of injuries per year, there has not been significant change; in 2004 Arlington had 51 accidents whereas in 2011, the last year of data, Arlington had 52 accidents.
The chart below shows the percent change in number of accidents, year to year (a negative percent means the number of accidents went down, which is good).
Overall, Alexandria City saw the greatest improvement, with a 70% decrease in accidents from 2004 to 2011. The Commonwealth saw an 11% decrease in number of accidents. Arlington was one of the few jurisdictions that saw an increase: 2%.
The database includes fatalities. Arlington is listed as having one fatality in 2011 and two overall. Fairfax had ten fatalities.
Of course, it would be nice to see these numbers go down. Keeping in mind that the number of cyclists on the road has gone up dramatically over this time, this means that these numbers, as a percentage of cyclists on the road or as a percentage of trips taken, have gone down - perhaps dramatically - and that's good.
It would be nice to know where these accidents are occurring (they probably didnt all happen at the Intersection of Doom: N Lynn St and Lee Hwy in Rosslyn). Of course if Arlington would fix that one intersection, they would see a dramatic decrease in the number of reported accidents.
About the Data
Methodology information on how the information is collected is not immediately apparent. One could guess that these are the accidents for which police reports are written (which means under reporting is possible). This is how Virginia describes the database:
The Traffic Records Management, Reporting and Analysis Division of the Virginia Highway Safety Office (VAHSO) manages the states' highway safety traffic records information system that houses millions of traffic crash records. Data that is collected, stored and analyzed by this Division is used for problem identification and resolution by local, state and federal entities across the Commonwealth.
This data is housed in the Traffic Records Electronic Data System (TREDS). TREDS, the first of its kind in Virginia, is a state-of-the-art traffic crash data system that automates and centralizes crash information from across the state. Its many benefits include the electronic submission of police crash reports, the electronic capture of GPS coordinates for reporting of specific crash locations, and the elimination of separate crash data repositories in multiple formats.
The Traffic Records Management, Reporting and Analysis Division engages in strategic planning to ensure the effective use of its existing Virginia traffic records information system to support and highlight the Commonwealth's safety programs and grant funding initiatives.