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Automatic driving lights control

"Blue sky effect" 

Two physical effects are responsible for these two switching characteristics:

  1. The spectrum of the ambient light ranges from ultraviolet light (UV light) through visible light, all the way to infrared light (IR light). The driver switches the driving light on not only due to the current surrounding brightness but also due to a personal assessment of the current driving situation. During good weather with a high UV proportion, the human eye takes account of the good visibility conditions. This is why the driver switches the driving light off early in the morning and late in the evening despite low brightness. During bad weather, the cloud cover filters the UV proportion of the ambient light. The driver takes account of the low visibility distance and switches the driving light on earlier despite adequate brightness. The currently used sensors that are suitable for automobiles measure the brightness in the range of visible light and partially in the range of infrared light. Due to the visibility conditions, they are unable to replicate human switching behavior.
  2. Due to the installation position, the RLS does not receive adequate brightness when the sun is low. The sensors for the automatic driving light switch are integrated in the rain sensor on the windscreen. The measured brightness in the sensor depends on the coverage angle and the direction of travel. When the sun is low, for example in autumn and winter, the brightness of the sun is not picked up. This means that the driving light remains on for a sustained period.

"Tunnel activation characteristics" 

In brightly lit tunnels, the automatic driving light control only switches on several seconds after entering the tunnel. The intensity of the tunnel lighting is sufficient to delay the driving light activation.

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