Abstract
The driver light, used by a motorist when normally travelling along the road in the dark, and the passing light, to which he switches over when approaching a vehicle coming from the other direction, both have to satisfy statutory requirements in order to ensure certain minimum visibility distance and not to cause excessive glare when passing the other vehicle. The American specifications differ from those in Europe. In this article both the requirements and the actual distribution of light are graphically illustrated for the driving light and for the passing light according compared and some typical details of the construction of European bulbs (philips "Duplo" bulb) and American "sealed beam" lamps are discussed.