Psychophysical measurement of headlight glare aftereffects on human contrast perception for optimizing a driving simulator

Visual disorders of drivers, like high glare sensitivity, come to a higher accident risk at night. In contrast, light-based assistance systems, as marking light, try to optimize the perception of the driver by presenting as much light as possible on critical objects. Consequently it is necessary to analyze the influence of glare on contrast perception in order to estimate possible positive effects on driving behavior and perception caused by light-based advanced driver assistance systems. Simulator studies offer the possibility to analyze critical situations under controlled conditions. However, for analyzing the effects of glare on driving behavior it is not possible to glare subjects while driving in a driving simulator without high technological expenditure. The aim of the presented study is to measure the effects of glare on human contrast perception by using psychophysical methods and to include the results in a driving simulation. To evoke the level of attention and situational awareness of a normal driving situation and to ensure controlled conditions, the glare of a standard headlight was combined with a simulator study. The recurring contrast perception is recorded by measuring the threshold of perception after glare. The results are implemented in a simulator environment by adjusting the display contrast. Thus the glare effects from oncoming vehicles on contrast sensitivity can be simulated. Hence, in the future, critical scenarios including glare effects can be tested in a driving simulator in order to test the influence of light-based advanced driver assistance systems on human perception.