Fast Shortest-path Distance Queries on Road Networks by Pruned Highway Labeling.

We propose a new labeling method for shortest-path and distance queries on road networks. We present a new framework (i.e. data structure and query algorithm) referred to as highway-based labelings and a preprocessing algorithm for it named pruned highway labeling. Our proposed method has several appealing features from different aspects in the literature. Indeed, we take advantages of theoretical analysis of the seminal result by Thorup for distance oracles, more detailed structures of real road networks, and the pruned labeling algorithm that conducts pruned Dijkstra's algorithm. The experimental results show that the proposed method is comparable to the previous state-of-the-art labeling method in both query time and in data size, while our main improvement is that the preprocessing time is much faster.