Document ID: chunk:federal_register_of_legislation:F2023C00919:body:0:p98
Version: federal_register_of_legislation:F2023C00919
Segment Type: other
Provision Reference: 
Character Range: 287875–290971

in percentage inclination, since the angles are small (for these small angles, 1 per cent is equal to 10 mrad).
If the inclination is expressed in percentage inclination, it can be calculated by means of the following formula:
 where:
             h1 is the height above the ground, in millimetres, of the above  mentioned characteristic point, measured on a vertical screen perpendicular to the vehicle longitudinal median plane, placed at a horizontal distance L.
             h2 is the height above the ground, in millimetres, of the centre of reference (which is taken to be the nominal origin of the characteristic point chosen in h1):
             L is the distance, in millimetres, from the screen to the centre of reference.
Negative values denote downward inclination (see Figure 1).
Positive values denote upward inclination.
Figure 1
Dipped beam downward inclination of a category M1 vehicle

Notes:
         1. This drawing represents a category M1 vehicle, but the principle shown applies equally to vehicles of other categories.
         2. Where the vehicle does not incorporate a headlamp levelling system, the variation in dipped beam inclination is identical with the variation in the inclination of the vehicle itself.
3.                                          Measurement conditions
3.1.                                    If a visual inspection of the dipped beam pattern on the screen or a photometric method is used, measurement shall be carried out in a dark environment (for example, a dark room) of sufficient area to allow the vehicle and the screen to be placed as shown in Figure 1.  Headlamp centres of reference shall be at a distance from the screen of at least 10 m.
3.2.                                    The ground on which measurements are made shall be as flat and horizontal as possible, so that the reproducibility of measurements of dipped beam inclination can be assured with an accuracy of  0.5 mrad (±0.05 per cent inclination).
3.3.                                    If a screen is used, its marking, position and orientation in relation to the ground and to the median longitudinal plane of the vehicle, shall be such that the reproducibility of the measurement of the dipped beam inclination can be assured with an accuracy of 0.5 mrad (0.05 per cent inclination).
3.4.                                    During measurements, the ambient temperature shall be between 10 and 30 °C.
4.                                          Vehicle preparation
4.1.                                    Measurements shall be carried out on a vehicle, which has travelled a distance of between 1,000 km and 10,000 km, preferably 5,000 km.
4.2.                                    Tyres shall be inflated to the full load pressure specified by the vehicle manufacturer.  The vehicle shall be fully replenished (fuel, water, oil) and equipped with all the accessories and tools specified by the manufacturer.  Full fuel replenishment means that the fuel tank shall be filled to not less than 90 per cent of its capacity.
4.3.                                    The