For a couple of years, the glare produced by various headlamp systems has been an expanding issue of discussion. Especially the introduction of gas discharge lamps led to a noticeable increase in complaints about discomfort glare. But what about visual performance? Do Xenon systems produce more glare than Halogen ones? Is there more glare from projection systems or from reflection systems? And how do the new LED headlamps fit in? This study examined disability glare of different headlamps which comply with legal requirements and of a misaligned headlamp. Disability glare is the extent to which glare reduces visual performance. Its cause is the veiling luminance in the human eye produced by the glare source. The amount of disability glare can be quantified by measuring the contrast sensitivity with and without a glare source. The threshold contrast increases with the amount of glare. ECE regulations R112 (Halogen headlamps) and R98 (gas discharge lamps) define the legal requirements of headlamps. Experiments clearly demonstrated that there are only marginal differences between disability glare generated by headlamps that comply with legal requirements. Results are completely different if the legal requirements are not fulfilled. This applies to both manipulated and misaligned headlamps and also in cases where headlamps are not automatically adjusted to level out great loads in the back of the car. Xenon systems can be expected to normally fulfil the legal requirements. Various reasons can be responsible for making Halogen systems generate excessive glare: manipulation ('tuning'), inexpertly replaced bulbs, or forgetting etc.
Disability glare of Halogen, Xenon and LED headlamp systems
Behinderung durch Blendung von Halogen-, Xenon- und LED-Scheinwerfersystemen
2007
7 Seiten, 5 Bilder, 3 Quellen
Conference paper
English
Discomfort and Disability Glare from Halogen and HID Headlamp Systems
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