Veh. Code, § 25258

(a) An authorized emergency vehicle operating under the conditions specified in Section 21055 may display a flashing white light from a gaseous discharge lamp designed and used for the purpose of controlling official traffic control signals.

(b) (1) An authorized emergency vehicle used by a peace officer, as defined in Section 830.1 of, subdivision (a), (b), (c), (d), (e), (f), (g), or (i) of Section 830.2 of, subdivision (n) of Section 830.3 of, subdivision (b) of Section 830.31 of, subdivision (a) or (b) of Section 830.32 of, Section 830.33 of, subdivision (a) of Section 830.36 of, subdivision (a) of Section 830.4 of, or Section 830.6 of, or a probation officer, as defined in Section 830.5 of, the Penal Code, in the performance of the peace officer’s duties, may, in addition, display a steady or flashing blue warning light visible from the front, sides, or rear of the vehicle.

(2) Before a probation officer operates an emergency vehicle with a blue warning light, the officer shall complete a four-hour classroom training course regarding the operation of emergency vehicles that is certified by the Standards and Training for Corrections Division of the Board of State and Community Corrections.

(3) This subdivision does not expand any existing authority of a probation officer to conduct a high-speed vehicle pursuit, nor does it change any existing training requirements for high-speed vehicle pursuits.

(c) Except as provided in subdivision (a), a vehicle shall not be equipped with a device that emits any illumination or radiation that is designed or used for the purpose of controlling official traffic control signals.