Document ID: chunk:federal_register_of_legislation:F2016C00338:front:0:p11
Version: federal_register_of_legislation:F2016C00338
Segment Type: other
Provision Reference: 
Character Range: 32112–34986

inside of the angles of geometric visibility no account is taken of obstacles, if they were already presented when the lamp was type-approved.

        If, when the lamp is installed, any part of the apparent surface of the lamp is hidden by any further parts of the vehicle, proof shall be furnished that the part of the lamp not hidden by obstacles still conforms to the photometric values prescribed for the approval of the device as an optical unit (see annex 3 of this Regulation).

        Nevertheless, when the vertical angle of geometric visibility below the horizontal may be reduced to 5 degrees (lamp at less than 750 mm above the ground) the photometric field of measurements of the installed optical unit may be reduced to 5 degrees below the horizontal;

       2.12.  "extreme outer edge", on either side of the vehicle means the plane parallel to the median longitudinal plane of the vehicle and touching the lateral extremity of the vehicle, disregarding the projection or projections

       2.12.1.  of rear-view mirrors,

       2.12.2.  of direction indicator lamps,

       2.12.3.  of front and rear position lamps and retro-reflectors;

       2.13.  "over-all width" means the distance between the two vertical planes defined in paragraph 2.12. above;

       2.14.  "A single lamp" means a device or part of a device, having one function and one apparent surface in the direction of the reference axis (see paragraph 2.8. of this Regulation) and one or more light sources.

        For the purpose of installation on a vehicle, a "single lamp" also means any assembly of two independent or grouped lamps, whether identical or not, having the same function, if they are installed so that the projection of their apparent surfaces in the direction of the reference axis occupies not less than 60 % of the smallest rectangle circumscribing the projections of the said apparent surfaces in the direction of the reference axis.

        In such a case, each of these lamps shall, where approval is required, be approved as a type "D" lamp.

        This possible combination does not apply to driving beam headlamps, passing beam headlamps and front fog lamps.

       2.15. "distance between two lamps" which face in the same direction means the shortest distance between the two apparent surfaces in the direction of the reference axis.

        Where the distance between the lamps clearly meets the requirements of the Regulation, the exact edges of apparent surfaces need not be determined;

       2.16.  "Operating tell-tale" means a visual or auditory signal (or any equivalent signal) indicating that a device has been switched on and whether or not it is operating correctly;

       2.17. "Circuit-closed tell-tale" means a visual (or any equivalent signal) indicating that a device has been switched on, but not indicating whether or not it