WHITE OR YELLOW LIGHT? PART 2

WIT OF GEEL LICHT? DEEL 2

The second article in this series deals with a number of physical aspects of the question as to whether yellow light is to be preferred for vehicle headlamps. First the perception within the human eye is discussed. Although the pictures are far from ideal, resulting from the structure of the eye, and although some effects such as diffraction and light scatter in the Ocular media would suggest a colour-dependence, it turns out that such a dependence, if present at all, is insignificant. It is likely that this is the result of the fact that several effects mentioned here counteract each other. Light scatter in the atmosphere as present in haze and mist depends upon the wavelength. Light with long wavelength (red light) is scattered less than short-wavelength light (blue). This effect might have some importance for aviation; for road traffic, however, it can be neglected firstly because the difference between (filtered) yellow light and white light is very small indeed, and secondly because in haze and mist visibility is still fairly good. In fog however, when visibility is reduced in such a manner that road traffic is impaired, the light scatter does not depend upon the wavelength. One may conclude that the physical phenomena do not give rise to arguments in favour of either white or yellow light. See also IRRD Abstract No. 211879. /TRRL/

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  • Corporate Authors:

    Royal Dutch Touring Club ANWB

    Wassenaarseweg 220, P.O. Box 93200
    The Hague,   Netherlands 
  • Authors:
    • SCHREUDER, D A
  • Publication Date: 1974

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Filing Info

  • Accession Number: 00097859
  • Record Type: Publication
  • Source Agency: Institute for Road Safety Research, SWOV
  • Files: ITRD, TRIS
  • Created Date: Sep 30 1975 12:00AM