Fast Replanning Incremental Shortest Path Algorithm for Dynamic Transportation Networks

Abstract

Incremental search technique is used to solve fully dynamic shortest path problems. It uses heuristics to focus their search and reuse information from previous searches to find solutions to series of similar search tasks much faster than is possible by solving each search task from the scratch. This paper focused on improving the speed of computation time, a novel algorithm has been developed that combines the incremental search ${\text{OLPA}}^{*}$ algorithm and bi-directional heuristic search approach. The idea of using the bi-directional heuristic search is to reduce the search space and then reduce the number of node expansions. This novel algorithm has been called the Bidirectional Lifelong ${\text{A}}^{*}$ algorithm [${\text{BiOLPA}}^{*}$]. The experimental results demonstrate that the ${\text{BiOLPA}}^{*}$ algorithm on road network is significantly faster than the ${\text{LPA}}^{*}$, ${\text{OLPA}}^{*}$ and ${\text{A}}^{*}$ algorithms, not only in terms of number of expansion nodes but also in terms of computation time. Furthermore, this research provides some additional measurements to back our claims regarding the effect of blocked link location to the goal and the performance of our ${\text{BiOLPA}}^{*}$ algorithm approach.