A Semi-materialized View Approach for Route Guidance in Intelligent Vehicle Highway Systems

EEcient path computation necessary for route guidance has been identiied as one of the key requirements for Intelligent Vehicle Highway Systems (IVHS) applications. While the current IVHS literature has focused on the application of search algorithms (typically, heuristic A* algorithms) to provide for compute-on-demand path nding, we propose a semi-materialized path view approach that pre-computes optimal paths. Advantages of our approach include (1) route computation is very eecient and no longer dependent on the number of route requests and (2) the storage overhead is less than for the full enumeration of all possible paths. In this paper, we present algorithms for incrementally updating the encoded path view structure in response to weight changes on the traac links of the underlying network, e.g., a slower link traversal time, a congestion, etc. Our algorithms are designed to operate correctly on cyclic graphs | given that IVHS maps typically correspond to highly interconnected grids. In this paper, we show that while our approach does not encode all paths, it omits paths only if they have undesirable path weights. We demonstrate the potential of our approach by presenting experimental results of evaluating our approach, and of comparing it against more conventional path searching algorithms.