California Code, Vehicle Code - VEH § 40830

(a) Where violation of the provision was required by a law of the federal government or by any rule, regulation, directive or order of any agency of the federal government, the violation of which is subject to penalty under an act of Congress or by any valid order of military authority.

(b) Where violation of the provision was required in order to comply with any regulation, directive, or order of the Governor promulgated under the California Emergency Services Act.