Inherent in the design of a low-beam (passing-beam) headlamp pattern is a trade-off between providing sufficient seeing for the driver using the headlamp and protecting oncoming drivers from glare. There are differences between the US and European approaches to this trade-off, stemming from a greater emphasis in Europe on protecting oncoming drivers from glare and on the ease of aiming the headlamp beam visually. Because neither approach appears to be superior overallin terms of visual performance, there is a strong economic impetus to develop a harmonized (common) beam pattern. This article summarizes two recent studies related to the issue of harmonization of beam patterns, and describes the current state of the harmonization efforts. The first of the two studies evaluated several current and proposed standards for low-beam headlamp patterns. The second study generated a proposal for partial harmonization, by recommending a small number (four) of the most important test points and their accompanying photometric limits. A slightly modified version of these four testpoints is currently being considered by international regulatory agencies for incorporation into existing standards. (A)
Samenvatting