Document ID: chunk:federal_register_of_legislation:F2018L01515:body:0:p15
Version: federal_register_of_legislation:F2018L01515
Segment Type: other
Provision Reference: 
Character Range: 41261–44090

centre-axle trailers which have at least one axle with steered wheels shall fulfil the conditions given in paragraph 6.3. However, for trailers with self-tracking steering equipment a test under paragraph 6.3. is not necessary if the axle load ratio between the un-steered and the self-tracking axles equals or exceeds 1.6. under all loading conditions.
 However for trailers with self-tracking steering equipment, the axle load ratio between un-steered or articulated steered axles and friction-steered axles shall be at least 1 under all loading conditions.
5.2.2. If the towing vehicle of a vehicle combination is driving straight ahead, the trailer and towing vehicle shall remain aligned. If alignment is not retained automatically, the trailer shall be equipped with a suitable adjustment facility for maintenance.
5.3. Failure provisions and performance
5.3.1. General
5.3.1.1. For the purposes of this Regulation the steered wheels, the steering control and all mechanical parts of the steering transmission 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 braking system) of the vehicle. Where the failure of any such part would be likely to result in loss of control of the vehicle, that part shall be made of metal or of a material with equivalent characteristics and shall not be subject to significant distortion in normal operation of the steering system.
5.3.1.2. The requirements of paragraphs 5.1.2., 5.1.3. and 6.2.1. shall also be satisfied with a failure in the steering equipment as long as the vehicle can be driven with the speeds required in the respective paragraphs.
 In this case paragraph 5.1.3. shall not apply for full power steering systems when the vehicle is stationary.
5.3.1.3. Any failure in a transmission other than purely mechanical shall clearly be brought to the attention of the vehicle driver as given in paragraph 5.4. When a failure occurs, a change in the average steering ratio is permissible if the steering effort given in paragraph 6.2.6. is not exceeded.
5.3.1.4. In the case where the braking system of the vehicle shares the same energy source as the steering system and this energy source fails, the steering system shall have priority and shall be capable of meeting the requirements of paragraphs 5.3.2. and 5.3.3. as applicable. In addition the braking performance on the first subsequent application, shall not drop below the prescribed service brake performance, as given in paragraph 2. of Annex 3 of this Regulation.
5.3.1.5. In the case where the braking system of the vehicle shares the same energy supply as the steering system and there is a failure in the energy supply, the steering system