One of the most important things in night-time traffic is vision. Car drivers should be able to get enough visual information for a safe driving. The headlamps of the car have to illuminate the road in a way, that the driver can see the road markings and the boundaries of the road. On the other hand the light distribution of headlamps should enable the driver to see obstacles, like pedestrians, on the road. The recognition distance of headlamps is a relevant and important safety feature, but also a quality mark of headlamps. The knowledge of the recognition distance makes a rating of headlamps and a comparison between different headlamps possible. The paper describes experiments aimed to predict the recognition distance on the basis of the light distribution of the headlamps. The visual criterion was 'just perceived', so that the observers didn't have to identify the visual target. For the experimental study a simple light distribution, consisting of a horizontal cut-off line which divided the distribution in two regions was used. The aim of this experiment was to determine the effect of the position of the cut-off line and of the perspective on the recognition distance. The conclusions drawn from the data analysis are as follows: I . The position of the cut off-line has a strong influence on the recognition distance. 2. The position of the observer (the perspective) has no effect on the recognition distance. This is valid for the range of parameters in the experiment. 3. The experiment shows that small differences in the luminance distribution lead to differences in the recognition distances. This must be considered in other experiments.
Examinations of the recognition distance of headlamps
Untersuchung des Erkennungsabstandes von Scheinwerfern
2005
11 Seiten, 5 Bilder, 3 Tabellen, 7 Quellen
Aufsatz (Konferenz)
Englisch
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