Document ID: chunk:federal_register_of_legislation:F2023C00228:reg:1:p6
Version: federal_register_of_legislation:F2023C00228
Segment Type: reg
Provision Reference: reg 1 (pt 6/15)
Character Range: 639454–642287

extending to either side of the V-V-line (see Figure 1) as specified in paragraph 6.2.1. of this Regulation.

       3. Adjustment of the symmetrical passing-beam headlamp:

       3.1. Horizontal adjustment:  The beam with the "cut-off" line shall be so positioned that the projected beam pattern appears approximately symmetrical to the V-V-line.

       3.2. Vertical adjustment:  After horizontal adjustment of the symmetrical passing-beam headlamp according to paragraph 3.1. above, the vertical adjustment shall be performed in such a way that the beam with its cut-off line is moved upwards from the lower position until the cut-off line is situated at nominal vertical position.  For nominal vertical adjustment the cut-off line is positioned on the V-V-line at 1° below the H-H-line.
       If the horizontal part is not straight but slightly curved or inclined, the cut-off line shall not exceed the vertical range formed by two horizontal lines which are situated from 3° left to 3° right of the V-V-line at 0.2° for class B and 0.3° for class A, C and D head lamps above and below the nominal position of the cut-off (see Figure 1).

       3.3. When the vertical adjustments of three different individuals differs by more than 0.2° for class B and 0.3° for class A, C and D head lamps, the horizontal part of the cut‑off line is assumed not to provide sufficient linearity or sharpness for performing visual adjustment.  In this case the quality of cut-off shall be tested instrumentally for compliance with requirements as follows.

       4. Measurement of the quality of cut-off:

       4.1. Measurements shall be performed by vertically scanning through the horizontal part of the cut-off line in angular steps not exceeding 0.05°

           (a) at either a measurement distance of 10 m and a detector with a diameter of approximately 10 mm.

           (b) or at a measurement distance of 25 m and a detector with a diameter of approximately 30 mm.

       The measurement of the cut-off quality shall be considered acceptable if the requirements of the paragraph 4.1.2. of this annex shall comply with at least one measurement at 10 m or 25 m.

       The measuring distance at which the test was determined shall be noted down in paragraph 9., Annex 1 "Communication form" of this Regulation.

        The scanning is performed from its lower position upwards through the cut-off line along the vertical lines at -3°, -1.5°, +1.5° and +3° from the V-V-line.  When so measured, the quality of the cut-off line shall meet the following requirements:

       4.1.1. Not more than one cut-off line shall be visible.[43]/

       4.1.2. Sharpness of cut-off:  if scanned vertically through the horizontal part of the cut-off line along the ± 2.5 -lines, the maximum value measured for:

       G = (log EV - log E(V