Four human observers with normal vision made 3200 independent judgments on large black-and-white Landolt C acuity targets. The testing was done at night on a length of road prepared so that acuity under sodium vapour lamps only and under mercury vapor lamps only could be compared. The observer-to-target distances were of the order of 30-50 metres. Analysis of results by signal detectability methods reliably showed that detection rates were higher for the sodium conditions. As the standardization of source luminance was inadequate, the study did not succeed in decisively demonstrating the superiority for sodium lighting with the particular acuity task involved; but does provide some evidence that when cost considerations are taken into account sodium road-lighting is likely to be a better choice than mercury lighting in standard application. It is recommended that similar research is best done in a well-equipped indoor laboratory, rather than on a road; and that acuities relying on color-contrast are most worthy of further study. /Author/

  • Corporate Authors:

    National Safety Council, Safety Research Info Serv

    425 North Michigan Avenue
    Chicago, IL  United States  60611
  • Authors:
    • Slater, S W
    • WHITE, M J
  • Publication Date: 1972

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 18 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00133526
  • Record Type: Publication
  • Source Agency: National Safety Council Safety Research Info Serv
  • Files: TRIS
  • Created Date: Aug 23 1976 12:00AM