Deeply tinted window glass transmits less light than less deeply tinted glass and therefore reduces driver visibility. Research was conducted to investigate the extent to which reduced levels of luminous (or light) transmittance in automobile windows are associated with decreased visibility of the kind of low and medium contrast objects that are likely to be seen in the roadway to the rear of passenger cars. The task of looking through the rear window for hazards before backing a car was simulated in a laboratory setting. Five targets (car, bicyclist, pedestrian, child, and debris) were shown to drivers from three age groups (18-55, 56-75, 76+) under conditions representing various combinations of luminous transmittance of the windows and luminance (brightness) contrast of the targets. The frequency of correct target detection was analyzed. The results varied by target. The car was always detected; however, detection probability decreased with reduced luminous transmittance for the child and roadway debris targets. For the bicyclist, pedestrian, child, and debris targets, detection probability decreased with lower luminance contrast and for older groups. The results of this experimental study, conducted under simulated conditions that were less demanding than real driving conditions, suggest that the safety of backing maneuvers is compromised for all drivers at the lowest luminous transmittance (darkest tinting) levels studied, and this is particularly so for elderly drivers for tinting levels darker than the 70% minimum luminous transmittance required by Federal Motor Vehicle Safety Standard 205.

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: 17 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00623679
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 31 1992 12:00AM