Abstract
To reveal the effect of driver assistance systems in automobile, some simulation programs are being developed. The program usually contains a vehicle model, a traffic flow generation model, a driver model, and others. In the program the driver model is difficult to depict because of its vagueness and inconsistency. The behavior of the driver consists of processes those are "attention, perception, cognition, prediction, decision-making, and operation." In the processes, "attention" and "prediction" are especially difficult to depict because they are quite internal process. Another difficulty is that the driver behavior in an emergency cannot be extrapolated from the usual behavior.
