Dynamic route guidance is a main feature when discussing traffic telematics systems. At the present time, several system concepts are in the development or implementation stage. The key elements of dynamic route guidance systems are illustrated in the following.Two approaches could be used when designing the system architecture: 1. Centralized routing in traffic information centers combined with on-board terminals. 2. Mobile routing by on-board navigation units which use information received from traffic information centers. The different approaches are presented in this paper. The influences on component design and the effects on communication needs are discussed. This leads to the “hybrid” system architecture which is presented including implementation examples.