Section 26508.

Every vehicle or combination of vehicles using compressed air at the wheels for applying the service brakes shall be equipped with an emergency stopping system meeting the requirements of this section and capable of stopping the vehicle or combination of vehicles in the event of failure in the service brake air system as follows:

(a) Every motor vehicle operated either singly or in a combination of vehicles and every towed vehicle shall be equipped with an emergency stopping system.

(b) Motor vehicles used to tow vehicles which use compressed air at the wheels for applying the service brakes shall be equipped with a device or devices with both a manual and automatic means of actuating the emergency stopping system on the towed vehicle as follows:

(1) The automatic device shall operate automatically in the event of reduction of the service brake air supply of the towing vehicle to a fixed pressure which shall be not lower than 20 pounds per square inch nor higher than 45 pounds per square inch.

(2) The manual device shall be readily operable by a person seated in the driver's seat, with its emergency position or method of operation clearly indicated. In no instance may the manual means be so arranged as to permit its use to prevent operation of the automatic means.

(c) Motor vehicles manufactured prior to 1964 shall be deemed to be in compliance with subdivisions (e) and (f) when equipped with axle-by-axle protected airbrakes using a separate air tank system for each of at least two axles, provided that each system independently meets all other requirements of this section. Each system shall be capable of being manually applied, released, and reapplied from the driver's seat but shall not be capable of being released from the driver's seat after any reapplication unless there is available a means which can be applied from the driver's seat to stop and hold the vehicle or combination of vehicles.

(d) Towed vehicles shall be deemed to be in compliance with this section when:

(1) The towed vehicle is equipped with a no-bleed-back relay-emergency valve or equivalent device, so designed that the supply reservoir used to provide air for the brakes is safeguarded against backflow of air from the reservoir through the supply line,

(2) The brakes are applied automatically and promptly upon breakaway from the towing vehicle and maintain application for at least 15 minutes, and

(3) The combination of vehicles is capable of stopping within the distance and under the conditions specified in subdivisions (k) and (l).

(e) If the service brake system and the emergency stopping system are connected in any way, they shall be so constructed that a failure or malfunction in any one part of either system, including brake chamber diaphragm failure but not including failure in the drums, brakeshoes, or other mechanical parts of the wheel brake assemblies, shall not leave the vehicle without one operative stopping system capable of complying with the performance requirements in subdivision (k).

(f) Every emergency stopping system shall be designed so that it is capable of being manually applied, released, and reapplied by a person seated in the driver's seat. The system shall be designed so that it cannot be released from the driver's seat after any reapplication unless immediate further application can be made from the driver's seat to stop and hold the vehicle or combination of vehicles. The emergency stopping system may also be applied automatically.

(g) No vehicle or combination of vehicles upon failure of the service brake air system shall be driven on a highway under its own power except to the extent necessary to move the vehicles off the roadway to the nearest place of safety.

(h) No vehicle or combination of vehicles shall be equipped with an emergency stopping system that creates a hazard on the highway, or increases the service brake stopping distance of a vehicle or combination of vehicles, or interferes in any way with the application of the service brakes on any vehicle or combination of vehicles.

(i) Any energy-storing device which is a part of the emergency stopping system shall be designed so that it is recharged or reset from the course of compressed air or other energy produced by the vehicle, except that energy to release the emergency stopping system may be produced by the driver's muscular effort from the driver's seat. No device shall be used which can be set to prevent automatic delivery of air to protected air supply reservoirs of motor vehicle emergency stopping systems when air is available in the service brake air supply system.

(j) Any vehicle manufactured on or after January 1, 1964, which uses axle-by-axle protected airbrakes as the emergency stopping system shall use a separate air tank system for each axle, except that motor vehicles equipped with a dual or tandem treadle valve system need have no more than two protected air tanks in such system, one for each valve.

(k) Every motor vehicle or combination of vehicles, at all times and under all conditions of loading, upon application of the emergency stopping system, shall be capable of:

(1) Developing a stopping force that is not less than the percentage of its gross weight tabulated herein for its classification.

(2) Decelerating in a stop from 20 miles per hour at not less than the feet per second per second tabulated herein for its classification, and

(3) Stopping from a speed of 20 miles per hour in not more than the distance tabulated herein for its classification, such distance to be measured from the point at which movement of the emergency stopping system control begins.

	EMERGENCY STOPPING SYSTEM REQUIREMENTS
	Classification of vehicle and combination of vehicles	Stopping force as a percentage of gross vehicle or combination weight	Deceleration in feet per second per second	Stopping distance in feet
A	Single-motor vehicles  ........................	16.7	5.5	90
B	Combination of vehicles  ........................	19.0	6.0	90
C	Single-motor vehicle with 3 or more axles manufactured prior to 1964  ........................	12.1	4.0	120

(l) Tests for deceleration and stopping distance shall be made on a substantially level, dry, smooth, hard surface that is free from loose material and where the grade does not exceed plus or minus 1 percent. No test of emergency stopping system performance shall be made upon a highway at a speed in excess of 25 miles per hour.

(m) The provisions of this section shall not apply to:

(1) Auxiliary dollies, special mobile equipment, or special construction equipment.

(2) Motor vehicles which are operated in a driveaway-towaway operation and not registered in this state.

(3) Disabled vehicles when being towed.

(4) Vehicles which are operated under a one-trip permit as provided in Section 4003.

(5) Vehicles which because of unladen width, length, height or weight may not be moved upon the highway without the permit specified in Section 35780.

(n) The emergency stopping system requirements specified in subdivision (k) shall not apply to a vehicle or combination of vehicles being operated under a special weight permit nor to any overweight authorized emergency vehicle operated under the provisions of Section 35002.

(o) Every owner or lessee shall instruct and require that the driver be thoroughly familiar with the requirements of this section. The driver of a vehicle or combination of vehicles required to comply with the requirements of this section shall be able to demonstrate the application and release of the emergency system on the vehicle and each vehicle in the combination.

(Amended by Stats. 1967, Ch. 1578.)