Document ID: chunk:federal_register_of_legislation:F2023C00153:front:0:p6
Version: federal_register_of_legislation:F2023C00153
Segment Type: other
Provision Reference: 
Character Range: 16429–19664

the headlamps setting can be adjusted by other means.
Where a headlamp providing a driving beam and a headlamp providing a passing beam, each equipped with its own lamp, are assembled to form a composite unit the adjusting device shall enable each optical system individually to be duly adjusted.
6.2.2.                              However, these provisions shall not apply to headlamp assemblies whose reflectors are indivisible. For this type of assembly the requirements of paragraph 7.3 of the present Regulation shall apply. Where more than one light source is used to provide the main beam, the combined functions shall be used to determine the maximum value of the illumination (Emax).
6.3.                                    The parts intended for holding the filament lamp in the reflector shall be so made that, even in darkness, the filament lamp can be mounted in no other position than the correct one.
6.4.                                    Complementary tests shall be done according to the requirements of annex 5 to ensure that in use there is no excessive change in photometric performance.
6.5.                                    If the lens of the headlamp is of plastic material, tests shall be done according to the requirements of annex 6.
7.                                          SPECIAL SPECIFICATIONS
7.1.                                    The correct position of the lens in relation to the optical system shall be unequivocally marked and be locked against rotation in service.
7.2.                                    For the measurement of the illumination produced by the headlamp, a measuring screen as described in annex 3 of this Regulation and a standard filament lamp (S1 and/or S2, Regulation No. 37) with a smooth and colourless bulb shall be used.
The standard filament lamp shall be adjusted to the applicable reference luminous flux according to values prescribed for these lamps.
7.3.                                    The passing beam shall have a cut-off sufficiently sharp in order that satisfactory aiming can practically be achieved with its aid.  The "cut-off" must be as straight and horizontal as possible over a range of at least 5 degrees on either side of the line v-v (see annex 3). When aimed according to annex 3, the headlamps shall meet the requirements specified in it.
7.4.                                    The beam pattern shall not present any lateral variations detrimental to good visibility.
7.5.                                    The illumination of the screen mentioned in paragraph 7.2 shall be measured by means of a photoelement having a useful area comprised within a square of 65 mm side.
8.                                          PROVISIONS CONCERNING COLOURED LENSES AND FILTERS
8.1.                                    Approval may be obtained for headlamps emitting either colourless or selective yellow light with an uncoloured filament lamp.  Expressed in CIE trichromatic co-ordinates, the corresponding colorimetric characteristics for yellow glasses or filters are as follows: Selective-yellow filter (screen or lens)
                            Limit towards red y> 0.138 + 0.58 x
                            Limit towards greed y< 1.29 x -0.1