It is known that wet weather conditions (e.g. spray and fog) reduce the normal visibility and perceptibility of vehicles referred from the point of view of the following traffic. It has been shown, that a vehicle's rear light is the only orientation at those conditions. Because of this, car drivers tend to hold too little space to the car they follow, increasing the risk of collisions. The topic of the project presented in the paper is the integration of optical sensors in rear lights and collection of drive data (e.g. velocity and steering-angle) to automatically adapt the level of visible light according to the environmental conditions of a moving car. One obtains the following values for a fog having a meteorological visibility of 60 metres: rear fog lamp 103 rn in daylight, 178 m at night; rear position lamps 58 rn in daylight, 124 m at night. These values are highly optimistic because they neglect the effect of the headlights of the observer's vehicle (veiling luminance). Even so, using lights of greater intensity substantially increases the visibility distances, but the absolute values in daylight and at night are very different for the same meteorological visibility. It was found that in night time fog an intensity of 140-200 cd is required for adequate visibility of a luminous signal but in daytime fog 100 times this intensity is required. Beam patterns of such lights should be symmetric left and right but it should have reduced intensity above the horizontal plane to reduce glare and backscatter. It was also found that red was the preferred colour The rear light is controlled through micro controllers. CAN and LIN bus technologies were used for communication between the rear light and other nodes in the car. Chip on board LEDs are used to achieve the desired values of light at desired range of temperatures.
Intelligent rear light - Constant perceptibility of light signals under all weather conditions
Intelligente Rückleuchte. Konstante Wahrnehmbarkeit der Lichtsignale unter allen Wetterbedingungen
2005
12 Seiten, 8 Bilder
Conference paper
English
Innovative tail lamp concept enhances perceptibility under bad weather conditions
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