Abstract
In this paper the traffic information system BIDIS is presented that utilizes the Europe-wide standardized GSM mobile telephone system to provide bidirectional communication. In addition, the worldwide available satellite positioning system GPS is used for determination of vehicle position. No additional infrastructure is necessary. Following an overview of services, the hardware and software concept of the in-vehicle unit, the dead reckoning algorithm and the man machine interface are presented. Finally, the semiconductor chips developed for the system are described and first practical results are discussed.