Shortest Alternative Path Finding on Road Network

Road network navigation services have become very popular over the past decade. The increased availability of road network data has triggered the development of a variety of new applications. However, returning only the shortest path is often not enough. Users are also interested in other benefits, such as alternative paths, which can be longer, but less frequently congested. This paper introduces to recommend k-Shortest Alternative Paths (k-SAP) problem seeking to recommend k alternative paths which are (a) as short as possible and (b) sufficiently dissimilar based on a user-controlled similarity threshold. This work proposes two algorithms that examine the paths from a source s to a target t in increasing order of their length and progressively construct the result set. The baseline algorithm builds upon a standard algorithm for computing k-Shortest Paths, followed by a filter step. The OnePass algorithm considers the overlap constraint in each expansion step while traversing the network. This paper evaluates the performance of both algorithms on real road networks and show that OnePass algorithm is always faster than Baseline algorithm.