The Influence of Scattered Light in Windshields on Driver's Vision during Night Driving

The investigation was carried out with a driving simulator, where 20 subjects had the task to drive in a passenger car on a synthetic, curved road which was displayed on a screen. The subjects could steer the car on the road with the steering wheel and by using the accelerator and the brake pedal they had free choise of the driving speed. Besides driving, the subjects had to detect visual signals at various defined contrasts to the surrounding field and to confirm detection. The number of right answers and the reaction times were taken as measure of the influence of scattered light on driver's vision through four different windshields, i.e. three clear windshields with haze levels of 0.2, 1.5 and 4.9 % and a green tinted windshield with a haze level of 0.2 %.