Bidirectional A ∗ Search for Time-Dependent Fast Paths
The computation of point-to-point shortest paths on time-dependent road networks has many practical applications, but there have been very few works that propose efficient algorithms for large graphs. One of the difficulties of route planning on time-dependent graphs is that we do not know the exact arrival time at the destination, hence applying bidirectional search is not straightforward; we propose a novel approach based on A ∗ with landmarks (ALT) that starts a search from both the source and the destination node, where the backward search is used to bound the set of nodes that have to be explored by the forward search. Extensive computational results show that this approach is very effective in practice if we are willing to accept a small approximation factor, resulting in a speed-up of several times with respect to Dijkstra’s algorithm while finding only slightly suboptimal solutions.
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- 12.Daganzo, C.: Reversibility of time-dependent shortest path problem. Technical report, Institute of Transportation Studies, University of California, Berkeley (1998)Google Scholar
- 13.Hart, E., Nilsson, N., Raphael, B.: A formal basis for the heuristic determination of minimum cost paths. IEEE Transactions on Systems, Science and Cybernetics SSC-4(2), 100–107 (1968)Google Scholar
- 14.Goldberg, A., Harrelson, C.: Computing the shortest path: A ∗ meets graph theory. In: Proceedings of the 16th Annual ACM-SIAM Symposium on Discrete Algorithms (SODA 2005), SIAM (2005)Google Scholar
- 15.Goldberg, A., Kaplan, H., Werneck, R.: Reach for A ∗ : Efficient point-to-point shortest path algorithms. In: Demetrescu, C., Sedgewick, R., Tamassia, R. (eds.) Proceedings of the 7th Workshop on Algorithm Engineering and Experimentation (ALENEX 2005), SIAM (2005)Google Scholar
- 17.Bauer, R., Delling, D.: SHARC: Fast and Robust Unidirectional Routing. In: Proceedings of the 10th Workshop on Algorithm Engineering and Experiments (ALENEX 2008), SIAM (to appear, 2008)Google Scholar
- 18.Ikeda, T., Tsu, M., Imai, H., Nishimura, S., Shimoura, H., Hashimoto, T., Tenmoku, K., Mitoh, K.: A fast algorithm for finding better routes by ai search techniques. In: Proceedings for the IEEE Vehicle Navigation and Information Systems Conference, pp. 291–296 (2004)Google Scholar
- 19.Goldberg, A., Werneck, R.: An efficient external memory shortest path algorithm. In: Demetrescu, C., Sedgewick, R., Tamassia, R. (eds.) Proceedings of the 7th Workshop on Algorithm Engineering and Experimentation (ALENEX 2005), pp. 26–40. SIAM (2005)Google Scholar
- 21.Kerner, B.S.: The Physics of Traffic. Springer, Berlin (2004)Google Scholar