The report prepared by the Technical Committee TC4.6 of the CIE, "Lighting of Public Highways", is not an official recommendation; the recommendations which are contained in it are given as advice and are not obligatory. It fixes the requirements which should be met by the lighting of traffic signs, i.e: (a) a mean luminance adequate for the entire sign, whilst maintaining a sufficient contrast between the different coloured sections; (b) a minimum uniformity of luminance in each homogeneous colorimetric section; (c) the different coloured zones must be defined with sufficient precision for the position of their trichromatic coordinates in the zones defined by the trichromatic diagram. Taking account of the novelty of this subject, this report should be considered as experimental, and it is to be hoped that the comparison of these recommendations with practical experience will make it possible to draw up the rules necessary for establishing a true `recommendations' from the CIE in the near future.
Abstract