Cal. INS § 11628.3

(a) Based on the actuarial and loss experience data available to each insurer, including the driving records of mature driver improvement course graduates, as recorded by the Department of Motor Vehicles, every admitted insurer shall provide for an appropriate percentage of reduction in premium rates for motor vehicle liability insurance for principal operators who are 55 years of age or older and who produce proof of successful completion of the mature driver improvement course provided for and approved by the Department of Motor Vehicles pursuant to Section 1675 of the Vehicle Code.

(b) The insured shall enroll in and successfully complete the course described in subdivision (a) once every three years in order to continue to be eligible for an appropriate percentage of reduced premium.

(c) The percentage of premium reduction required by subdivision (a) shall be reassessed by the insurer upon renewal of the insured’s policy. The insured’s eligibility for any percentage of premium reduction shall be effective for a three-year period from the date of successful completion of the course described in subdivision (a), except that the insurer may discontinue the reduced premium rate if the insured is in any case:

(1) Involved in an accident for which the insured is at fault, as determined by the insurer.

(2) Convicted of a violation of Division 11 (commencing with Section 21000) of the Vehicle Code, except Chapter 9 (commencing with Section 22500) of that division, or of a traffic related offense involving alcohol or narcotics.

(d) The percentage of premium rate reduction required by subdivision (a) does not apply in the event the insured enrolls in, and successfully completes, an approved course pursuant to a court order provided for in Section 42005 of the Vehicle Code. Nothing in this subdivision precludes an insured from also enrolling in a driver improvement course.