Optimal Time-dependent Sequenced Route Queries in Road Networks

TL;DR

This paper introduces an A* based algorithm for optimal time-dependent sequenced route queries in road networks, efficiently finding fastest routes passing through specified points of interest considering real-world travel time variations.

Contribution

It presents the first algorithm to handle time-dependent travel times for sequenced route queries, improving efficiency over previous non-time-aware solutions.

Findings

Up to 100x faster than previous methods

Effectively handles real and synthetic data sets

Guarantees optimal routes with admissible heuristic

Abstract

In this paper we present an algorithm for optimal processing of time-dependent sequenced route queries in road networks, i.e., given a road network where the travel time over an edge is time-dependent and a given ordered list of categories of interest, we find the fastest route between an origin and destination that passes through a sequence of points of interest belonging to each of the specified categories of interest. For instance, considering a city road network at a given departure time, one can find the fastest route between one's work and his/her home, passing through a bank, a supermarket and a restaurant, in this order. The main contribution of our work is the consideration of the time dependency of the network, a realistic characteristic of urban road networks, which has not been considered previously when addressing the optimal sequenced route query. Our approach uses the A* search paradigm that is equipped with an admissible heuristic function, thus guaranteed to yield the optimal solution, along with a pruning scheme for further reducing the search space. In order to compare our proposal we extended a previously proposed solution aimed at non-time dependent sequenced route queries, enabling it to deal with the time-dependency. Our experiments using real and synthetic data sets have shown our proposed solution to be up to two orders of magnitude faster than the temporally extended previous solution.