This research was designed to determine a small set of low-beam test points for recommendation as common test points throughout the world. The recommendation is a compromise among the following three set of inputs: (1) expert opinion, based on a worldwide survey of 119 experts in lighting and vision; (2) current practice, based on an analysis of candela matrixes of 150 production low beams, and (3) scientific evidence concerning visibility and glare under nighttime driving conditions. Expert opinion and scientific evidence did not fully converge on the same test points, with the main difference being in the amount of light recommended for points at which objects need to be seen. While experts suggested light levels comparable to current production outputs, the recommendations based exclusively on scientific evidence would call for light levels of more than ten times the current levels. Therefore, the test points based exclusively on scientific evidence should be viewed only as ideal test points, but we should aim in the future to explore technologies that would make approximations to these test points feasible. The compromise recommendation calls for four test points, and it takes into account different test voltages, throughout the world. If the proposed set of test points for partial harmonization meet with acceptance, extending this approach to determining additional test points for full harmonization should be considered. (A)
Abstract