Abstract
ACC as first implemented driver assistance system will give the driver the possibility to drive in a convenient manner. The system lay-out is described as a support system. This implicates that the driver has to supervise during operation. Because of today sensor technology (sensing relevant obstacles - obstacle itself; road-geometry) the available systems will have restrictions in use. One of the major restriction is driving under poor whether conditions. Either radar nor infrared technology is able to fulfill the whole functionality autonomous of the driver supervision. This is the reason for the need to detect restrictions of the human being to provide automatic control without an adequate possibility of the driver to supervise the system. Because of poor distance estimation of the human being either in good and much more at poor conditions, the driver needs support to ensure safe traffic.