Cal. Vehicle Code § 25259.1

(a) Any vehicle operated by a disaster service worker who has received training in accordance with subdivision (b) and used by that worker in the performance of emergency or disaster services ordered by lawful authority during a state of war emergency, a state of emergency, or a local emergency, as those terms are defined in Section 8558 of the Government Code, may display flashing amber warning lights to the front, sides, or rear while at the scene of the emergency or disaster. (b) Any disaster service worker operating a vehicle that displays flashing amber warning lights shall receive a training course from the public agency, disaster council, or emergency organization described in Section 3101 of the Government Code concerning the safe operation of the use of flashing amber warning lights prior to operating a vehicle that displays flashing amber warning lights. (c) A person operating a vehicle that is authorized to display flashing amber warning lights under this section shall either completely cover or remove those lights when the lights are not in use.