Automotive forward lighting has to meet two antithetical requirements increasing forward visibility and decreasing glare - and therefore requires restrictive optical control. However, forward lighting, if it is dimmable according to traffic density and ambient lighting conditions, may be able to more efficiently control glare to oncoming and preceding drivers. A study in the 1970s proposed a 'city beam', having lower luminous intensity (e.g., 20-100 cd) than conventional low-beam headlamps, and proved that in well-lit areas headlamps can be dimmed to reduce glare while maintaining drivers' visual performance. Although it might have been difficult to apply the 'city beam' concept to automotive practice in the 1970s, recent advanced forward lighting technology could spur putting this concept into practice. Before implementing the dimmable forward lighting, however, it is important to investigate if forward lighting can be dimmed without compromising visual performance. This paper explores the interaction between fixed roadway lighting and vehicle forward lighting on visual performance and glare. The results of the study indicate that target visibility is improved as ambient illuminance on the roadway pavement is increased. Automotive forward lighting little improved target visibility when roadway lighting was present, except for a small effect at 15 deg to the right. These results imply that within the range of lighting conditions used in this study, to reduce the impact of headlamp glare to oncoming drivers, headlamp intensity can be dimmed while maintaining drivers' visual performance in lit areas.
Interaction between fixed roadway lighting and vehicle forward lighting
Wechselwirkung zwischen fester Fahrbahnbeleuchtung und Fahrzeugscheinwerferlicht
2003
12 Seiten, 7 Bilder, 2 Tabellen, 12 Quellen
Aufsatz (Konferenz)
Englisch
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