Abstract
Visibility distances to targets on the road have been measured in simulated full-scale opposing situations between two passenger cars on low beams. The level of low beam illumination above the cut-off was varied in four levels from half the normal to four times the normal illumination of European (ECE) low beams. The results show that the optimum (absolute) level of illumination above the cut-off is related to the reflection properties of the visual targets. The most important parameter seems to be the relation between the level of illumination just above and just below the cut-off. (A)