Cal. Ins. Code § 11580.1
(b) Every policy of automobile liability insurance to which subdivision (a) applies shall contain all of the following provisions:
(c) In addition to any exclusion provided in paragraph (3) of subdivision (b), the insurance afforded by any policy of automobile liability insurance to which subdivision (a) applies, including the insurer’s obligation to defend, may, by appropriate policy provision, be made inapplicable to any or all of the following:
(8) Any motor vehicle or class of motor vehicles, as described or designated in the policy, with respect to which coverage is explicitly excluded, in whole or in part.
“The insured” as used in paragraphs (1), (2), (3), and (4) shall mean only that insured under the policy against whom the particular claim is made or suit brought. “An insured” as used in paragraphs (5) and (6) shall mean any insured under the policy including those persons who would have otherwise been included within the policy’s definition of an insured but, by agreement, are subject to the limitations of paragraph (1) of subdivision (d).
(d) Notwithstanding paragraph (4) of subdivision (b), or Article 2 (commencing with Section 16450) of Chapter 3 of Division 7 of, or Article 2 (commencing with Section 17150) of Chapter 1 of Division 9 of, the Vehicle Code, the insurer and any named insured may, by the terms of any policy of automobile liability insurance to which subdivision (a) applies, or by a separate writing relating thereto, agree as to either or both of the following limitations, the agreement to be binding upon every insured to whom the policy applies and upon every third-party claimant:
(1) That coverage and the insurer’s obligation to defend under the policy shall not apply nor accrue to the benefit of any insured or any third-party claimant while any motor vehicle is being used or operated by a natural person or persons designated by name. These limitations shall apply to any use or operation of a motor vehicle, including the negligent or alleged negligent entrustment of a motor vehicle to that designated person or persons. This agreement applies to all coverage provided by that policy and is sufficient to comply with the requirements of paragraph (2) of subdivision (a) of Section 11580.2 to delete coverage when a motor vehicle is operated by a natural person or persons designated by name. The insurer shall have an obligation to defend the named insured when all of the following apply to that designated natural person:
(C) He or she is an insured under a separate automobile liability insurance policy issued to him or her as a named insured, which policy does not provide a defense to the named insured.
An agreement made by the insurer and any named insured more than 60 days following the inception of the policy excluding a designated person by name shall be effective from the date of the agreement and shall, with the signature of a named insured, be conclusive evidence of the validity of the agreement.
That agreement shall remain in force as long as the policy remains in force, and shall apply to any continuation, renewal, or replacement of the policy by the named insured, or reinstatement of the policy within 30 days of any lapse thereof.
(f)
(1) On and after January 1, 1976, no policy of automobile liability insurance described in subdivision (a) shall be issued, amended, or renewed in this state if it contains any provision that expressly or impliedly excludes from coverage under the policy the operation or use of an insured motor vehicle by the named insured in the performance of volunteer services for a nonprofit charitable organization or governmental agency by providing social service transportation. This subdivision shall not apply in any case in which the named insured receives any remuneration of any kind other than reimbursement for actual mileage driven in the performance of those services at a rate not to exceed the following: