Document ID: chunk:federal_register_of_legislation:F2023C00142:front:0:p9
Version: federal_register_of_legislation:F2023C00142
Segment Type: other
Provision Reference: 
Character Range: 24057–26948

the user.  Such initial or selective setting may consist, for example, of fixing either the optical unit at a given angle on the vehicle or the light source(s) at a given angle in relation to the optical unit. In all cases, only two different and clearly distinct settings, one for right-hand and-one for left-hand traffic, shall be possible, and the design shall preclude inadvertent shifting from one setting to the other or setting in an intermediate position.  Where two different setting positions are provided for the light source, the components for attaching the light source to the reflector must be so designed and made that, in each of its two settings, the light source will be held in position with the precision required for headlamps designed for traffic on only one side of the road.  Conformity with the requirements of this paragraph shall be verified by visual inspection and, where necessary, by a test fitting.

       5.5. On headlamps designed to provide alternately a driving beam and a passing beam, any mechanical, electromechanical or other device incorporated in the headlamp for switching from one beam to the other [7/] must be so constructed that:

       5.5.1. the device is strong enough to function 50,000 times without suffering damage despite the vibrations to which it may be subjected in normal use;

       5.5.2. in the case of failure it is possible to obtain the passing beam automatically;

       5.5.3. either the passing beam or the driving beam can always be obtained without any possibility of the mechanism stopping in between the two. positions;

       5.5.4. the user cannot, with ordinary tools, change the shape or position of the moving parts.

       5.6. Complementary tests shall be done according to the requirements of annex 4 to ensure that in use there is no excessive change in photometric performance.

       5.7. Light transmitting components made of plastic material shall be tested according to the requirements of annex 5.

       5.8. The headlamp and ballast system shall not generate radiated or power line disturbances to cause a malfunction of other electric/electronic systems of the vehicle. [8/]

       6.  ILLUMINATION

       6.1. General Provisions

       6.1.1. Headlamps shall be so made that with suitable gas-discharge light source they give adequate illuminance without dazzle when emitting the passing beam, and good illumination when emitting the driving beam.

       6.1.2. The illumination produced by the headlamp shall be determined by means of a vertical screen set up 25 m forward of the headlamp and at right angles to its axes (see paragraph 6.2.6. and annex 3 to this Regulation), or by any equivalent photometric method.

       6.1.3. The headlamp using a removable gas-discharge light source shall be deemed satisfactory if the photometric requirements set in the present paragraph 6. are