This International Standard specifies the dimensions of special warning lamps for road vehicles, in order to ensure interchangeability and accurate positioning, bearing in mind the rapid change of light intensity from such devices in a vertical cross-section of the projected beam.
It also specifies (see Annex A) methods for testing the magnetic-base mountings used to install special warning lamps directly on the steel sheet of the roof or body of a vehicle (special warning lamps of Category D).
NOTE In certain countries and international bodies, the term “light” is sometimes used instead of “lamp”.