California Code, Vehicle Code - VEH § 25259

(a) Any authorized emergency vehicle may display flashing amber warning lights to the front, sides, or rear.

(b) A vehicle operated by a police or traffic officer while in the actual performance of his or her duties may display steady burning or flashing white lights to either side mounted above the roofline of the vehicle.

(c) Any authorized emergency vehicle may display not more than two flashing white warning lights to the front mounted above the roofline of the vehicle and not more than two flashing white warning lights to the front mounted below the roofline of the vehicle. These lamps may be in addition to the flashing headlamps permitted under Section 25252.5.