Effects of Realistic Levels of Dirt on Light Distribution of Low-Beam Headlamps

摘要

This study evaluated changes in the light output of low-beam headlamps as afunction of dirt accumulated during a 482-km route, representing a 10-day amount of driving for a typical U.S. driver. The complete route was traversed on three separate occasions, under each of the following environmental conditions: summer while dry, summer while wet, and winter with road salt. Candela matrices were obtained for a rectangular central portion of the beam, extending from 20 deg left to 20 deg right, and from 5 deg down to 5 deg up (in 0.5 deg steps). Photometry for each of two lamps was performed twice after the completion of each drive, first 'as is' and then after cleaning.