Modelling Turning Restrictions in Traffic Network for Vehicle Navigation System

Vehicle navigation is currently the most widespread and successful consumer application of GIS-T. It is based on positional accurate data and comprehensive transportation-related content. A specially-made navigable database is essential for the key functions of the vehicle navigation systems, for example, route finding and driver guiding. There are lots of research challenges in generating a satisfied navigable database. Among them the data modelling is the most important comparing with representation, data processing, etc., especially the modelling of the turn restrictions of the traffic network. There are three levels of data modelling for the vehicle navigation systems, i.e., conceptual modeling, logical modeling, and algorithmic modeling. The authors of this paper think that special consideration should be put onto the algorithmic model, because it represents not only the relationships between the transportation elements but also the real-time and dynamic traffic restrictions in the traffic network. This paper discussed firstly the properties of the turning restrictions in road networks. The model in conceptual model (GDF 4.0) and logical model (UNETRANS) are introduced. Concerning the algorithmic model, the authors analyzed the disadvantages of the commonly used data structure for representing the turning restrictions. And proposed a new link-based data structure, where a node-link table is used to represent the connectivity of the road network, and a link-link table is used to represent the turning restrictions. The algorithm for route finding was also modified accordingly. The results of the experiment show that the efficiency of route finding is obviously improved with the new method. * Corresponding author.