(a) Every school bus shall, and every church bus may, in addition to any other equipment and distinctive markings required by this chapter, be equipped with signal lamps mounted as high and as widely spaced laterally as practicable, which shall be capable of displaying to the front two alternately flashing red lights located at the same level and to the rear two alternately flashing red lights located at the same level, and these lights shall have sufficient intensity to be visible at 500 feet in normal sunlight.
(b) The alternately flashing lighting described in subsection (a) of this section shall not be used on any vehicle other than a school bus, a church bus, or an authorized emergency vehicle.