This paper presents a comparative approach to explain the performance of various in-vehicle route guidance systems. In the first part, the aims and the operating modes of an in-vehicle route guidance system are described, then an overview of the functional descriptions of various systems is presented and several basic considerations for performance evaluation are illustrated. Furthermore, studies of different cases in four developed countries are summarized; and several crucial problems that are related to the future development of in-vehicle route guidance systems are discussed and suggestions are also made.
