Efficient Modified Bidirectional A* Algorithm for Optimal Route-Finding

A* algorithm, a kind of informed search, is widely used for finding an optimal car route, because the location of starting and ending point are known beforehand. Unidirectional A* algorithm guarantees an optimal route but requires considerable search time. On the other hand, bidirectional A* algorithm, usually known faster than unidirectional A*, does not guarantee the route found to be optimal, if the search ends when the forward and backward search meet in the middle. It may even take longer than unidirectional search to find an optimal route. In this paper, a new modified bidirectional A* algorithm which takes less search time and guarantees an optimal route is proposed. To evaluate the efficiency of the proposed algorithm, several experiments are conducted in real urban road environment and the results show that the algorithm is very effective in terms of finding an optimal route and search time.

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