A first look at visually aimable and harmonized low-beam headlamps
Sivak, Michael; Flannagan, M. J.; Miyokawa, T.
University of Michigan, Ann Arbor, Transportation Research Institute
AbstractThis analytical study evaluated the performance of 40 first-generation low-beam headlamps that were either visually/optically aimable (VOA) or that met the GTB harmonized beam pattern, by comparing these low beams to conventional U.S., European, and Japanese low beams. The following aspects of headlamp performance were considered: visibility of pedestrians, visibility of pavement delineation, visibility of retroreflective traffic signs, visibility of vehicle rear reflex reflectors, visibility of targets near the road expansion point, glare directed towards oncoming drivers, glare directed towards rearview mirrors of preceding drivers, glare reflected from wet pavement towards oncoming drivers, and foreground illumination. For each performance aspect, typical geometric situations (points in space) were specified in terms of longitudinal, lateral, and vertical positions, and the corresponding visual angles from each of the two headlamps were calculated. The effects of the novel low beams were quantified by calculating the percent changes in luminous intensity directed from both lamps towards the points in space representing the performance aspects. The results are presented separately for the VOA lamps that are aimable on the left side (VOL lamps) and the right side (VOR lamps), as well as for the harmonized lamps. The present results could be used by lamp designers to maximize the advantages of the future versions of these novel low beams, while minimizing their disadvantages.
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