Document ID: chunk:federal_register_of_legislation:F2023C00154:reg:1:p9
Version: federal_register_of_legislation:F2023C00154
Segment Type: reg
Provision Reference: reg 1 (pt 9/15)
Character Range: 119137–121876

cut-off differ by more than 0.2°, 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°
     At either a measurement distance of 10 m and a detector with a diameter of approximately 10 mm.
     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 paragraphs 4.1.1. to 4.1.3. 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 recorded in paragraph 9. of the communication form in Annex 2 of this Regulation.
     The scanning is performed from downwards upwards through the cut-off line along the vertical lines at -2.5° and +2.5° 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.
     4.1.2. Sharpness of cut-off:
     If scanned vertically through the horizontal part of the cut-off line along vertical lines at ±1° from the v‑v line, the maximum value measured for the sharpness factor G of the cut-off line shall not be less than 0.08 where:
     G = (log EV - log E (V + 0.1°))
     4.1.3. Linearity
     The part of the cut-off line which serves vertical adjustment shall be horizontal from 3° left to 3° right of the v‑v line. This requirement is satisfied, if the vertical positions of the inflection points according to paragraph 3.2. above at 3° left and right of the v‑v line do not deviate by more than ±0.20°.
     5. Instrumental vertical adjustment
     If the cut-off line complies with the above quality requirements, the vertical beam adjustment can be performed instrumentally. For this purpose the inflection point where d2 (log E) / dv2 = 0 is positioned on the v‑v line and below the h‑h line. The movement for measuring and adjusting the cut-off line shall be upwards from below the nominal position.
Annex 10

Overview of operational periods concerning test for the stability of photometric performance
Abbreviations:  P: passing-beam lamp
D: driving-beam lamp (D1 + D2 means two driving-beams)
F: front fog lamp
All following grouped headlamps and front fog lamps together with the added marking symbols are given as examples and are not exhaustive.

:  means a cycle of 15