UMTRI authors Michael J. Flannagan, Mary Lynn Buonarosa, Joel M. Devonshire, Brandon Schoettle, and Naoko Takenobu have published extensive new data regarding HID headlamp usage rates in the U.S. by area and time of night.
This study was therefore designed to obtain direct measurements of the proportion of vehicles with HID headlamps in nighttime traffic. Eight sites (two in each of four metropolitan areas) were selected, and traffic at those sites was video recorded between the hours of 7:00 p.m. and 10:00 p.m.
The observations were made in late February and early March 2008, when those evening hours were dark and virtually all vehicles had their headlamps on. Video recording was done with diffraction gratings mounted on the cameras so that the type of headlamps—HID or tungsten-halogen (TH)—could be easily discriminated by the spectrally dispersed headlamp images. Investigators later scored the videos, counting the numbers of vehicles (except for motorcycles) in terms of headlamp type (HID or TH), and number of headlamps on (both, one, or none).The proportions of vehicles with HID headlamps varied by more than an order of magnitude, from 1.5% to 20%, across the eight sites. The proportion of HID headlamps did not vary over time within the three-hour observation periods. The proportions of TH-equipped vehicles with only one headlamp not functioning varied from 0.18% to 1.3% across the eight sites.
The 22nd annual meeting of the Industry Affiliation Program at the University of Michigan was held in Ann Arbor, USA on December 2. The full-day meeting included a review of the 14 research projects performed in 2008 with the affiliate funding, and presentations by the industry members concerning important future research topics. About 60 persons attended from the 36 member companies.
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