Contraction Hierarchies with A* for digital road maps

Abstract

One of the most successful recent approaches for solving single source single destination problems in graphs is the Contraction Hierarchies (CH) algorithm, originally published by {[}3]. The general algorithm consists of two phases: Firstly, a total order on the nodes in the graph is calculated. Secondly for queries, a modified bi-directional Dijkstra-search is performed on the hierarchy implied hereby. Relying on Dijkstra's algorithm, CH makes no use of the geometric information contained within digital road maps. We propose A{*}-like modifications of the original query algorithm that double query speed. Results are presented in a benchmark using a map from the OpenStreetMap project.