One of the major preconditions of safe driving is that drivers correctly perceive and interpret the relevant objects and elements of the current traffic situation and that they consider these elements in planning and controlling their behaviour. Such elements may be other drivers, the condition of the street or traffic signs. For each of these elements drivers do not just have to perceive them but they must understand them according to their relevance to their goals. In addition, drivers must also make assumptions about the future actions or states of these elements. For example, perceiving a car coming from the right when entering a crossroads is far from being enough in order to react accordingly. The driver must interpret this car according to its relevance to his own goal, that is, safely passing the crossroads. He has to take into account whether he or the car from the right has to give way. But even this is not enough to select the appropriate action. If the other car has to give way, the driver will try to assess from the speed of the car whether the other car will indeed stop. A concept that has recently become rather popular in aviation psychology and that aims at describing and integrating these different cognitive processes is called situation awareness.