The first problem of the present paper was to find out in which way vehicle conspicuity in various levls of twilight is influenced by the use of running lights. Three running light intensities, 100, 200, and 300 ed were used. The ressults indicate that no increase in conspicuity occurs until the shaky illumination is down at about 1000 lux. Very small differences were found between the different light intensities. The second problem studied dealt with the effect of running lights on distance judgement to oncoming vehicles. Two psychophysical methods were used: a method of adjustment and a method of constant stimuli with limited exposure time. The running light intensities in the first part were 100 and 300 ed. No effect of light intensity was found. The running light intensities using the second method were 300 and 900 ed. The results here indicate a tendency to underestimate the distance to a vehicle with running lights. The underestimation increases with increasing running light intensity. The results from these two experiments suggest that the main conspicuity increment as a result of the use of running lights occurs at daylight levels below 1000 lux sky illumination. The use of running lights also seem to increase the safety margin to oncoming vehicles since the subjective distance is shorter than the objective one. /Author/

  • Corporate Authors:

    Uppsala University, Sweden

    Department of Psychology, Tradgardsgaten 20
    75220 Uppsala,   Sweden 
  • Authors:
    • Horberg, U
  • Publication Date: 1977

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 27 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00165925
  • Record Type: Publication
  • Report/Paper Numbers: Report 215
  • Files: TRIS
  • Created Date: Apr 12 1978 12:00AM