There are some interfering elements, which are able to influence the signal functions of a car's rear light. One of these elements is the sensitivity to external light sources, which is able to affect the intensity of the rear lamps by the impact of direct light sunrays in a flat angle. Recognition of the signals could be made more difficult or impossible. This effect is called phantom light effect. Today the regulations of the ECE do not contain these influences. A survey has shown that 50 % of all crossroad accidents and nearly 65 % of all rear-end collision accidents could be avoided if the driver would have had only half a second more reaction time. Another survey has shown that reaction times under static conditions are about 600 msec. The objective of this study is to detect the influence of external light sources on the recognition of current rear lamps by the measurement of reaction times. Eight current rear lamps with different optical characteristics are chosen out to this survey In this experiment reaction times and subjective evaluations should be detected by involving psychophysical tests about 20 persons with static conditions at the Light tunnel of the LTI Karlsruhe. Measurement of reaction times are discussed by various charts, for instance two charts represent the reaction times of the signals indicator and brake of eight actual rear lamps. Optical characteristics of rear lamps have a main influence on the signal recognition affected by external light sources. The expectations are confirmed that reaction times of the not irradiated signals of the rear lamps are about 600 msec. Generally the increasing of the reaction times by sun simulation is larger for the indicator as for the brake. Furthermore the expectance has been confirmed that the reaction times of the signals with sun simulation are longer than the signals of not irradiated rear lamps. Further charts represent the subjective evaluation of 20 test persons of the signal indicator and brake with and without sun simulation. The task is to give each signal of the tested rear lamps a mark between one and five at the two conditions with and without sun simulation. One means a good rear lamp and five a bad one. Test criteria's are the intensity, the face and the colour of the signals as well as a possible glare.
The phantom light effects in modern car rear light combinations
Der Phantomlichteffekt bei der Kombination von modernen Fahrzeugrücklichtern
2007
8 Seiten, 7 Bilder, 4 Quellen
Conference paper
English