Fog Headlamp-Visibility Investigations and Performance Requirements for Redefinition in Adaptive Headlamp Systems

During haze or fog situations particularly at night time the visual range of drivers can be decreased in the dependence of the transmittance of the atmosphere. Today fog headlamps with an inclination of the cut-off-line at β = -2% and a focus on improved side illumination can support a better guidance along the road course, but can't compensate the disadvantages during fog concerning the reduced driver's visual range along his own driving lane. Improving the range of fog headlamps in comparison to standard fog beam patterns can provide safety benefits during night time fog conditions.

Some results of investigations concerning fog beam pattern will be given in this lecture and the conclusions for an improved fog beam pattern will be described. In the field of future adaptive headlamp systems further improvements can be provided by activating the fog headlamp or by adapting the beam pattern to different fog density conditions automatically.

Taking into account that several sensors for the detection of the visual range are under development and automatic adaptation of the car's beam pattern to the weather condition will be possible in the future, the driver's requirements for different fog situations should be defined.