Quantitative comparisons of factors influencing the performance of low-beam headlamps

Abstract

This study compared the quantitative influence of a variety of factors on the performance of low-beam headlamps. The factors included were vertical aim, horizontal aim, mounting height, lateral separation, lens dirt, lamp voltage, number of functioning lamps, vehicle type, beam pattern and light source. The following aspects of headlamp performance were considered: visibility of pedestrians, visibility of road delineation, visibility of vehicle reflex reflectors, visibility of rettoreflective traffic signs, visibility of targets near the road expansion point, glare directed towards oncoming drivers, glare reflected from wet pavement towards oncoming drivers, glare directed towards rearview mirrors of preceding vehicles, and foreground illumination. A sales-weighted average US beam pattern, with lamps mounted at sales-weighted average locations, formed the basis for most of the analyses. The results indicate that, from among the factors studied, vertical aim is overwhelmingly the most important factor in influencing the performance of low-beam headlamps. The second most important factor is the number of functioning lamps. The main implication of this study is that major improvements in current (fixed as opposed to adaptive) low-beam headlighting could be achieved primarily by better control of vertical aim and by use of longer-life headlamps.

Get full access to this article

View all access options for this article.

References

Bhise V.D. , Matle C.C. and Hoffmeister D.H. CHESS model applications in headlamp systems evaluation SAE Technical Paper Series 840046 (Warrendale PA: Society of Automotive Engineers) ( 1984)

Sivak M. , Flannagan M.J. , Traube E.C. , Kojima S. and Aoki M.

Low-beam headlamps: effects of realistic dirt levels on light output

Lighting Res. Technol. 29 15-22 (1997)

Perel M. , Evaluation of headlamp beam patterns using the Ford CHESS program Proceedings of the Tenth International Technical Conference on Experimental Safety Vehicles pp 223-229 (Washington DC: US Department of Transportation) (1985)

Bhise V.D. , Farber E.I. , Saunby C.S. , Troell G.M. , Walunas J.B. and Bernstein A. Modeling vision with headlights in a systems context SAE Technical Paper Series 770238 (Warrendale PA: Society of Automotive Engineers) (1977)

Sivak M. , Flannagan M.J. , Kojima S. and Traube E.C. A market-weighted description of low-beam headlighting patterns in the US SAE Technical Report Series 980317 (Warrendale PA: Society of Automotive Engineers) (1998)

Sivak M. , Flannagan M.J. , Budnik E. , Flannagan C. and Kojima S. The locations of headlamps and driver eye positions in vehicles sold in the US Ergonomics 40 872-878

Sivak M. , Flannagan M.J. , Traube E.C. and Miyokawa T.

Do changes in voltage result in proportional changes throughout headlamp beam patterns?

Lighting Res. Technol. 311-3 (1999)

Copenhaver M.M. and Jones E. Measurement of headlamp aim and the electrical and photmeric performance characteristics of rear lighting systems. Report No. DOT HS 807 930 (Washington DC: US Department of Transportation) (1992)

Lighting handbook: reference and application 8th edn (New York: Illuminating Engineering Society of North America) (1993)

10.

Rys M. , Konz S. and Russell E. Headlight outages Presented at the SAE Congress , Detroit (1993)

11.

Sivak M. , Flannagan M.J. and Sato T. Light output of US, European and Japanese low-beam headlamps Transportation Res. Rec. 1456 99-111