Document ID: chunk:federal_register_of_legislation:F2023C00919:body:0:p21
Version: federal_register_of_legislation:F2023C00919
Segment Type: other
Provision Reference: 
Character Range: 69058–72240

and parallel to that axis. For the purposes of determining the lower, upper and lateral edges of the device, only horizontal and vertical planes shall be considered.
2.10.                                The "apparent surface" for a defined direction of observation means, at the request of the manufacturer or his duly accredited representative, the orthogonal projection of:
Either the boundary of the illuminating surface projected on the exterior surface of the lens;
Or the light-emitting surface;
Only in the case of a light-signalling device producing variable luminous intensities, its apparent surface that may be variable as specified in paragraph 2.7.1.3. shall be considered under all conditions permitted by the variable intensity control, if applicable.
In a plane perpendicular to the direction of observation and tangential to the most exterior point of the lens.  Different examples of the application of apparent surface can be found in Annex 3 to this Regulation.
2.11.                                "Axis of reference" (or "reference axis") means the characteristic axis of the lamp determined by the manufacturer (of the lamp) for use as the direction of reference (H = 0°, V = 0°) for angles of field for photometric measurements and for installing the lamp on the vehicle.
2.12.                                "Centre of reference" means the intersection of the axis of reference with the exterior light emitting surface; it is specified by the manufacturer of the lamp.
2.13.                                "Angles of geometric visibility" means the angles which determine the field of the minimum solid angle in which the apparent surface of the lamp is visible.  That field of the solid angle is determined by the segments of the sphere of which the centre coincides with the centre of reference of the lamp and the equator is parallel with the ground.  These segments are determined in relation to the axis of reference.  The horizontal angles ß correspond to the longitude and the vertical angles α to the latitude.
2.14.                                "Extreme outer edge" on either side of the vehicle, means the plane parallel to the median longitudinal plane of the vehicle and touching its lateral outer edge, disregarding the projection:
2.14.1.                          Of tyres near their point of contact with the ground, and of connections for tyre pressure gauges;
2.14.2.                          Of any anti-skid devices mounted on the wheels;
2.14.3.                          Of devices for indirect vision;
2.14.4.                          Of side direction-indicator lamps, end outline marker lamps, front and rear position lamps, parking lamps, retro reflectors and side marker lamps.
2.14.5.                          Of customs seals affixed to the vehicle and of devices for securing and protecting such seals.
2.14.6.                          Of service-door lighting systems on vehicles of categories M2 and M3 as specified in paragraph 2.7.
2.15.                                "Overall dimensions" means the distance between the two vertical planes defined in paragraph 2.14. above.
2.15.1.                          "Overall width"