Chapter 6.5. Motor Carrier Safety * Article 8. General Equipment Requirements Brakes--School Buses and Farm Labor Vehicles.
The following additional brake requirements shall apply to school buses and farm labor vehicles:
(a) Air Brakes--Type 1 school buses having 10 or more rows of seats and manufactured after January 1, 1970, and prior to April 1, 1977, shall be equipped with full compressed air brakes. Type 1 school buses equipped with air brakes and manufactured after January 1, 1953, shall have at least two reservoirs connected in series. On all school buses manufactured on or after July 1, 1970, the air-actuated devices outside the service and emergency brake systems shall also be provided with a reservoir equal to at least six times the total volume at full travel of all auxiliary devices supplied by the reservoir. The reservoir requirement for the air-actuated devices outside the service and emergency brake systems shall not apply to school buses manufactured on or after March 1, 1975, in compliance with FMVSS 121 (49 CFR 571.121).
(b) Warning Devices--Type 1 school bus brake systems shall have warning devices as follows:
(1) Air brakes shall have a buzzer or other audible warning signal and a visual, air-operated, flag-type warning device, both used exclusively for the brake system. Both devices shall give a continuous warning when the air supply pressure in the first reservoir to receive air from the compressor, or any service reservoir, drops below a fixed pressure as specified by Vehicle Code Section 26506. The flag-type device is not required on vehicles manufactured on or after March 1, 1975, in compliance with FMVSS 121 (49 CFR 571.121).
(2) Vacuum brakes shall have a buzzer or other audible warning signal and a visual, vacuum-operated, flag-type warning device, both used exclusively for the brake system. They shall provide continuous warning to the driver when the vacuum in the supply system drops to 8 inches of mercury and less. The requirement for the flag device shall not apply to vehicles manufactured with a dual or split type service brake system powered by power-assist vacuum chambers.
(3) The visual warning devices required in (1) and (2) shall be readily visible to the driver when seated in the normal driving position.
(4) Override switches are prohibited for audible warning devices required in (1) and (2).
(5) The requirements in (1) and (2) for warning devices to be used exclusively for the brake system shall not be construed to prohibit multichannel warning devices that monitor other vehicle systems in addition to the brake system if such devices provide a clear brake system warning that cannot be activated by any of the other monitored vehicle systems.
(c) Brake System Modification--Brakes on Type 1 school buses may be modified only with the written approval of the school bus chassis manufacturer or by using brake system options of a type available from the bus manufacturer and represented by the bus manufacturer as suitable for use on the specific model school bus. Modifications shall not render the brake system in violation of the provisions of this title or of any other law or regulation. Modifications shall not render inoperative any item of brake-related equipment nor diminish any aspect of performance of a brake system manufactured in compliance with FMVSS 121, except as permitted by written ruling of the National Highway Traffic Safety Administration.
(1) Air system cleaning devices, such as automatic condensate drains and air dryers, are not considered a modification of the brake system if they are installed in accordance with the component manufacturer's instructions.
(2) A conversion from an air brake chamber that has an air applied parking brake or emergency stopping system function to a brake chamber that has a spring applied parking brake or emergency stopping system function, or vice versa, is not considered a modification if the conversion is made in accordance with the substitute component manufacturer's instructions.
(3) Any advisory recommendations by the component manufacturer shall be considered mandatory. The instructions shall be retained by the school bus operator for reference by California Highway Patrol personnel for comparison with the completed installations.
(d) Service Brake System--Type 1 school buses manufactured on and after January 1, 1968, shall comply with the following requirements:
(1) Foot Pedal Travel--The travel of hydraulic brake foot pedals shall not exceed 60 percent of the available travel when measured statically at the minimum pedal force required for compliance with Vehicle Code Sections 26454 on stopping distance.
(2) Air or Vacuum Reservoirs--The combined volume of all service reservoirs shall be at least 12 times the combined volume of all service brake chambers at maximum travel of the pistons or diaphragms.
(3) Check Valves--Brake systems safeguarded by the check valve referenced in Section 1245(b) of this title shall meet the following requirements:
(A) Air Brake System--At least half of the required air reservoir capacity shall be safeguarded to prevent the stored air from being depleted by any failure or leakage in the connection to the source of compressed air. Air supply for the service brakes shall be protected so that failure of the air-actuated devices outside the service brake system will not drop the service brake supply system pressure to less than 60 pounds per square inch.
(B) Vacuum Brake System--The required vacuum brake system reservoir capacity shall be safeguarded to prevent the stored vacuum from being depleted by any failure or leakage in its connection to the source of vacuum. The supply of vacuum for all devices or systems other than the brake system shall be drawn from between the brake system check valve and the source of vacuum.
(e) Emergency Stopping System--Type 1 school buses manufactured after January 1, 1968, shall comply with the following emergency stopping system requirements:
(1) The brakes shall be capable of being applied, released, and reapplied by the driver but shall not be capable of being released from the driver's seat after any reapplication unless energy is available for an immediate reapplication.
(2) The brakes shall be manually applied and released under modulated control by the driver to maintain directional stability during a complete emergency stop.
(3) Failure or malfunction of any part in either the emergency stopping system or the service brake system shall not leave the vehicle without operative brakes capable of stopping the vehicle loaded up to the manufacturer's gross vehicle weight rating within the requirements of California Vehicle Code Section 26508(k)(3).
This provision does not apply to a failure in the mechanical parts of the wheel brake assemblies or the brake pedal and linkage to the brake valve or master cylinder.
(4) School buses manufactured on or after March 1, 1975, in compliance with FMVSS 121 (49 CFR 571.121) and maintained in compliance with that standard, shall be deemed in compliance with this subsection.
(f) Reservoir Capacity--The reservoir capacity of school buses and farm labor vehicles shall be sufficient to complete one operation of the doors after the engine has stopped and the brakes have been fully applied.
Vehicle Code 31401
Vehicle Code 34508
Vehicle Code 31401
Vehicle Code 34508
(Amended by Register 95, No. 19.)