California Code of Regulations
Title 13 - Motor Vehicles
Division 2 - Department of the California Highway Patrol
Chapter 2 - Lighting Equipment
Article 7 - Mounting Requirements
Section 696 - School Bus Warning Lamps

(a) Number of Lamps and Required Locations. Four warning lamps are required on each school bus. Two alternately flashing lamps shall be rigidly mounted on the front, one at each side, at the same height above the top of the windshield; and two alternately flashing lamps shall be rigidly mounted on the rear, one at each side, at the same height, with the bottom edge of each lens not lower than the top line of the side window openings. A panel shall be installed to serve as a background for warning lamps that extend above the top of a school bus.

(b) Operating Switches. School bus warning lamp switches operated manually by the driver shall be located within easy reach of the driver's position.

(c) Pilot Indicator. A bright visible flashing signal not less than 12.7 mm (0.5 in.) in diameter shall be included in the circuit to give a clear and unmistakable indication to the driver when the warning signals are turned on. The indicator shall not be obscured from the driver's view by any part of the vehicle.

(d) Spacing and Visibility. Front and rear warning lamps shall be spaced as far apart laterally as is practicable, and in no case shall the distance between lamps be less than 100 cm (39 in.). Visibility of front and rear warning lamps shall be unobstructed by any part of the vehicle from 5 deg above to 10 deg below horizontal and from 30 deg to the right to 30 deg to the left of the center line of the lamps.

(e) Warning Lamp Installation Dates. Warning lamps installed on school buses after 1965 shall be red Class C warning lamps. Those installed before 1966 and meeting requirements in effect at time of installation may continue to be used on the school buses on which they were installed.