A review of the literature concerning factors that influence visibility and privacy through automotive glass was performed. Thirty-three articles were summarized and critiqued. Critiques were based upon the contribution to the current state of knowledge. While research in this area has been conducted for more than 40 years, substantial controversy remains. This is particularly true of research that addresses the effects of transmittance on driver visual performance. With few exception, the existing research suggests that factors such as transmittance, wear, rake, and dirt all contribute significantly to limiting driver visual performance. The results of studies vary due to the variety of tasks examined, the number of variables involved, and the performance criteria selected. Almost no literature exists that addresses the issue of privacy as it relates to automotive glass. On the basis of a re-examintion of previously reported data, it appears that transmittance has generally a linear effect on driver visual performance with a reduction in transmittance levels from 100% to 50% resulting in a reduction in visual performance of 10-20%.
Abstract