If the inner and outer surface of a windscreen are not exactly parallel, for instance as a result of bending, double images from light sources may appear in the driver's view. These defects of the optical quality of windscreens are already visible for some drivers, if the angular distance of the double image is only 6 minutes of arc from the first image. More than half the drivers become aware of double images and make complaints about the impairment, if they have an angular distance of 10 minutes of arc. Beside an expressed detraction from comfort, test persons deplore an irritation, which might lead to a higher risk. In a field test, drivers among others show a higher muscular tension under the influence of double images. This and other results of a field test are considered in detail and discussed under the aspect of an ECE regulation on the quality of car glass that tolerates 15 minutes of arc in the main field of view. (A)
Samenvatting