Effects of car window tinting on visual performance : a comparison of elderly and young drivers

A major concern in allowing the tinting of car front side windows to 35% visible light transmittance (VLT) is that tasks performed through these windows often require the rapid detection of low-contrast, unilluminated targets. If the tinting interferes with detection of targets then road safety may be compromized. Speed of cognitive and visual processing declines with age; performance on backward pattern masking tasks can indicate this slowing in processing speed. Two experiments compared performance of the young and elderly adult on two backward pattern masking tasks with levels of VLT from 100 to 20%. The first experiment found a decrement in performance for the elderly at 63% VLT and for all participants at 20% VLT. The second experiment found a decrement in performance for the elderly at 35% VLT. It was concluded that road safety may be compromized if the front side windows of cars are tinted to 35% VLT.