According to the california vehicle code, you can send in a written declaration to contest any traffic ticket. Then the officer must send in his letter to explain the case. A judge reads both sides of the case and decides if you are guilty/not guilty. The cool thing is that if you are found guilty you can still request a trial de novo (a new trial.. but it has to be a normal trial in front of a judge, not another written one) so there’s no way to lose.
The other nice thing is that if the police officer does not send in his letter, your case is dismissed by default.
This option is not listed in the letter you receive after you got the ticket. But you can go to the clerks office to ask for a written declaration form. They will give you without asking any questions. There are detail instructions on the form.