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Forschungsstelle
METAS
Projektnummer
F-5116.30140
Projekttitel
flickereffekt im Strassentunnel

Texte zu diesem Projekt

 DeutschFranzösischItalienischEnglisch
Schlüsselwörter
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Kurzbeschreibung
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Projektziele
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Abstract
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Umsetzung und Anwendungen
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Publikationen / Ergebnisse
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Erfasste Texte


KategorieText
Schlüsselwörter
(Englisch)
light flicker effect, road tunnels, road safety, uniform tunnel lighting, vehicle driver performance
Kurzbeschreibung
(Englisch)

In road tunnels, the flicker effect is said to generally impair driving behavior. To avoid potential effects on road safety, it is therefore recommended internationally that minimum values for the uniformity of tunnel lighting be observed. Because the flicker effect in the frequency range between 5 Hz and 10 Hz is perceived as particularly unpleasant, this frequency range is avoided as a precautionary measure for lighting in Swiss road tunnels. In concrete terms, this means that the lamps in a road tunnel can only be placed at certain distances depending on the intended driving speed. However, it should be noted that the principles for determining the flicker range in road tunnels are not well established internationally and there is hardly any scientifically reliable evidence available. The current lighting standard SN 40 551-1 refers to this uncertain state of knowledge and explicitly mentions that in the frequency range between 4 Hz and 15 Hz only "(...) in the absence of reliable, quantitatively formulable findings and out of caution (...)" through-illumination should be avoided.

Projektziele
(Englisch)
In essence, the effects of modern lighting technologies on the cognitive and visual performance of vehicle drivers must be analyzed experimentally. The results should be used to formulate appropriate measures for future handling of the flicker effect. The following goals are to be to be achieved:

Objective 1: To demonstrate the influence of new lighting technologies on the flicker effect and traffic safety in road tunnels;
Objective 2: To formulate proposals for the possible adaptation of lighting specifications, in particular with regard to the type and position of the light source, light color, light intensity, exposure duration and light influence.
Abstract
(Englisch)

For a scientific analysis of the flicker effect, specific subject tests were carried out in a specially equipped driving simulator at ETH using "virtual reality". Perceptual effects, eye movements, subjective perception and behavioral effects were measured, which are impaired by the simulation of the flicker effect. Collaboration with ETH, scians GmbH and METAS was ensured for the realization of the research project. 

The test results show that the flicker effect, which is subjectively perceived as disturbing, is not limited to the medium frequencies (4...15 Hz), but also exists at higher frequencies (16...20 Hz). Higher frequencies worsen the ride quality; this was manifested in the experiment by increased lateral and longitudinal acceleration of the vehicle. Age also increases the poorer ride quality at higher frequencies. In addition, light bands were perceived as significantly more pleasant than point sources.

Umsetzung und Anwendungen
(Englisch)

Thus, the original assumptions that led to the «prohibition window» (4...15 Hz) cannot be considered as still valid. It seems that there is a general deterioration of the (subjectively perceived) ride comfort and the (objectively determined) driving quality with increasing flicker frequency. Thus, the existing Swiss standard SN 40 551-1 (Part 1: Lighting requirements, terms and quality characteristics) should be revised on this point. At the same time, it seems appropriate to continue the present research and to investigate the higher frequency range above 15 Hz.

Publikationen / Ergebnisse
(Englisch)

It was clearly established that the flicker effect is not limited to the medium frequencies (4...15 Hz), but also exists at higher frequencies (16...20 Hz). It is therefore recommended that the influence of these higher frequencies should also be taken into account. As a result, the extent to which the existing Swiss standard SN 40 551-1 (Part 1: Lighting requirements, terms and quality characteristics) needs to be revised in this respect.

The work also showed that continuous rows of lights were generally perceived as more pleasant (which is not surprising). However, since the objectively quality of ride is directly influenced by this, it should be examined whether continuous light bands should be installed in tunnels if this is necessary (e.g. high traffic volume, large number of lanes). New road tunnels are currently (as of 2021) only equipped with LED technology; this type is usually used for refurbishments. As this high luminance in spot form, glare (which was not investigated in this study) is promoted. Luminaire designs with a more wide-area light output would counteract this and would very probably have a positive influence on driving quality.