EFFECTS OF REDUCED TRANSMITTANCE FILM ON AUTOMOBILE REAR WINDOW VISIBILITY

Deeply tinted window glass transmits less light than less deeply tinte d glass and therefore reduces driver visibility. The task of looking t hrough the rear window for hazards before backing a car was simulated in a laboratory setting with five targets (car, bicyclist, pedestrian, child, and debris) shown to drivers (ages 18-55, 56-75, and 76 +) at various combinations of luminous transmittance of the windows and lumi nance (brightness) contrast of the targets. Analyses showed that the f requency of correct target detection varied by target. The car was alw ays detected, but detection probability decreased with reduced luminou s transmittance for the child and roadway debris targets. For the bicy clist, pedestrian, child, and debris targets, detection probability de creased with lower luminance contrast and for older age groups. The re sults suggest that the safety of backing maneuvers is compromised for all drivers at the darkest tinting levels studied. This is particularl y true for elderly drivers for tinting levels darker than the 70% mini mum luminous transmittance required by federal standards.