| 2.1. | A spring braking system shall not be used as a service braking system. However, in the event of a failure in a part of the transmission of the service braking system, a spring braking system may be used to achieve the residual performance prescribed in paragraph 5.2.1.4. of this Regulation provided that the driver can graduate this action. In the case of power-driven vehicles, with the exception of tractors for semi-trailers meeting the requirements specified in paragraph 5.2.1.4.1. of this Regulation, the spring braking system shall not be the sole source of residual braking. Vacuum spring braking systems shall not be used for trailers. | a0c0 |