The navigation system has become one of the essential IT gadgets, especially to the drivers. In addition to the basic functionality of finding a shortest path between two nodes, recent navigation systems are required to provide extra intelligent services to the users. In this paper, we propose a Voronoi-based hybrid navigation system based on 3G wireless communication that has been commercially deployed recently. Our proposed system has the server-client architecture. Based on the Voronoi-based map data, the server receives real-time traffic information through the TPEG and re-computes optimal road network dynamically. For a user request whose optimal path has been affected by the real road traffic data, the server sends modified routing information to the user. We have implemented a prototype navigation system and carried out extensive experiments. The experimental result shows that our proposed system achieves an excellent performance.