Search Results

The most frequent adverse weather situation zones is the rain situation. Therefore the lighting properties of the traffic situation with a wet road surface are measured in great detail. The target of the investigations is to show the necessity and the potential for an improvement of headlights for this situation. In the first part of this paper the results of experiments are shown, which analyse the visual performance of drivers during glare in wet road situations. In the second part rating experiments concerning comfortable luminance levels in front of the car during rainfall are described. To illustrate the result of these experiments the obtained rating parameters are applied to one example of a headlight beam pattern for a situation with wet road surface.

The goal of the investigations was to find out if there is a correlation between the luminance distribution on the lens surface of projection type headlamps (e.g. maximum luminance) and the average subjective glare rating (discomfort glare) of subjects under night time traffic conditions. The luminance distributions of different projection type systems are measured with a luminance measurement system and compared concerning their characteristics. For the validation a glare rating experiment has been carried out with a standard type glare source of different size and luminance peaks similar to projection lens luminances. It was found out that for glare peaks up to a diameter of α = 2′ (observation angle) the candle power of the glare source is the proper parameter to calculate the subjective glare effect. For larger sizes of the glare sources there is a dependency to the diameter of the glare source for the glare effect.

The introduction of innovative new technologies is related to aspects of safety and to human factors as comfort level and visual appearance. The intelligent headlamp system that is currently being developed allows the combination of the different aspects of driving comfort and safety. The top performing headlamp generations of the future will be the successors of the today’s standard low beam. By using the sensor information available in the car, the light distribution will be adapted to different driving situations and generate an optimized light distribution. Relaxed and safe driving is the goal. Investigations concerning adaptive headlamps are presented. Highway, country road, curves and turning situations are examined by investigating detection distances of standard objects and by rating safety and comfort. Photometric measurements rating glare effects during curve road driving for different headlamp control algorithms are carried out.