A market-weighted description of low-beam headlighting patterns in the U.S.: 2004

Abstract

This study was designed to provide updated photometric information about current U.S. low-beam headlamps. The sample included 20 headlamps manufactured for use on the 20 bestselling passenger vehicles for model year 2004 in the U.S. The vehicles sampled represent 39% of all vehicles sold in the U.S. The lamps were purchased directly from vehicle dealerships. The photometric information for each lamp was weighted by the sales figure for the corresponding vehicle. The results are presented in tabular form for the 25th-percentile, 50th-percentile (median), and 75th-percentile luminous intensities (from 45° left to 45° right, and from 5° down to 7° up). The results are also presented in graphical form for the median luminous intensities (from 45° left to 45° right, and from 10° down to 10° up), as well as for the median illuminance incident on vertical surfaces at various locations on the roadway.