Cal. Ins. Code § 11580.8
The Legislature declares it to be the public policy of this state to avoid so far as possible conflicts and litigation, with resulting court congestion, between and among injured parties, insureds, and insurers concerning which, among various policies of liability insurance and the various coverages therein, are responsible as primary, excess, or sole coverage, and to what extent, under the circumstances of any given event involving death or injury to persons or property caused by the operation or use of a motor vehicle.
The Legislature further declares it to be the public policy of this state that Section 11580.9 of the Insurance Code expresses the total public policy of this state respecting the order in which two or more of such liability insurance policies covering the same loss shall apply, and such public policy is not to be changed or modified by any provision of the Vehicle Code except in those express cases where the requirements of Article 2 (commencing with Section 16450) of Chapter 3 of Division 7 of the Vehicle Code apply with regard to a policy of liability insurance certified as provided in Section 16431 of the Vehicle Code.
Ca. Ins. Code § 11580.8