There's a state database compiled by CHP called SWITRS that tracks traffic accidents. You can find it here. http://iswitrs.chp.ca.gov/Reports/jsp/userLogin.jsp

We don't call it out by name in the story, but it's the kind of existing government system that could be expanded to provide a better, official count of street racing deaths.

Our Los Angeles Times team has mined SWITRS in the past for other stories, like these:

http://graphics.latimes.com/la-pedestrians/

http://graphics.latimes.com/la-bike-hit-and-runs/