Division 2.2.1.2

The equipment providing service, secondary and parking braking may have common components, provided that they fulfil the following conditions:

1. 2.2.1.2.1.

   There shall be at least two controls, each corresponding to a different braking system, independent of each other and readily accessible to the driver from his normal driving position. For all categories of vehicles, every brake control device (excluding endurance braking system control device) shall be designed in a way that it returns to the fully-off position when released. This requirement shall not apply to a parking braking system control device (or that part of a combined control device) when it is mechanically locked in an applied position or it is utilised for the secondary braking or in both cases.

2. 2.2.1.2.2.

   The control device of the service braking system shall be independent of the control device of the parking braking system.

3. 2.2.1.2.3.

   Where the service and secondary braking systems have the same control device, the effectiveness of the linkage between that control device and the various components of the transmission systems shall not be liable to deteriorate after a certain period of use.

4. 2.2.1.2.4.

   Where the service and secondary braking systems have the same control device, the parking braking system shall be so designed that it can be actuated when the vehicle is in motion. This requirement shall not apply if the vehicle's service braking system can be actuated, even partially, by means of an auxiliary control.

5. 2.2.1.2.5.

   In the event of a breakage of any component other than the brakes or the components specified in point 2.2.1.2.7, or of any other failure of the service braking system (malfunction, partial or total exhaustion of an energy reserve), the secondary braking system or that part of the service braking system which is not affected by the failure shall be able to bring the vehicle to a halt in the conditions prescribed for secondary braking.

6. 2.2.1.2.6.

   In particular, where the secondary braking system and the service braking system have a common control device and common transmission:

   1. 2.2.1.2.6.1.

      F1Where the service braking system is actuated by the muscular energy of the driver assisted by an energy source or one or more energy reserves, the secondary braking performance shall, in the event of failure of that assistance, be capable of being ensured by the muscular energy of the driver assisted by the energy reserves, if any, which are unaffected by the failure, the force applied to the control device not exceeding the prescribed maxima.

   2. 2.2.1.2.6.2.

      If the service braking force and transmission depend exclusively on the use, controlled by the driver, of an energy reserve, there shall be at least two completely independent energy reserves, each provided with its own transmission likewise independent; each of them may act on the brakes of only two or more wheels so selected as to be capable of ensuring by themselves the prescribed degree of secondary braking without endangering the stability of the vehicle during braking; in addition, each of the those energy reserves shall be equipped with a warning device. In at least one of the air reservoirs of each service braking circuit a device for draining and exhausting is required in an adequate and easily accessible position.

   3. 2.2.1.2.6.3.

      If the service braking force and transmission depend exclusively on the use of an energy reserve, one energy reserve for the transmission is deemed to be sufficient, provided that the prescribed secondary braking is ensured by the action of the driver's muscular energy acting on the service brake control device and the requirements of point 2.2.1.5 are met.

7. 2.2.1.2.7.

   Certain parts, such as the pedal and its bearing, the master cylinder and its piston(s) (hydraulic systems), the control valve (hydraulic or pneumatic systems), the linkage between the pedal and the master cylinder or the control valve, the brake cylinders and their pistons (hydraulic or pneumatic systems), and the lever-and-cam assemblies of brakes, shall not be regarded as liable to breakage if they are amply dimensioned, are readily accessible for maintenance, and exhibit safety features at least equal to those prescribed for other essential components (such as the steering linkage) of the vehicle. Where the failure of any such part would make it impossible to brake the vehicle with a performance at least equal to that prescribed for the secondary braking system that part shall be made of metal or of a material with equivalent characteristics and shall not be subject to significant distortion in the normal operation of the braking systems.