A new website allows bicyclists to report incidents with cars, provided you record the license plate of the offending vehicle. From Bikex:
The Bikex Database is an online resource to identify, document, and prosecute drivers who harass, abuse, or endanger bicycle riders. Currently the database is for the Los Angeles area. New locations and features are coming soon.Your personal information will not be released without your permission or sold under any circumstances. For more information as to how this program works please visit the FAQ page. Submissions from skateboarders, pedestrians, and sympathetic drivers are welcome.