Usage of RAPTOR for travel time minimizing journey planner

Abstract

The goal of this paper is to enhance RAPTOR journey planning algorithm to return a comprehensive list of journeys to the end user, offering a wide range of meaningful alternatives. We optimize for minimal length of the journeys, while considering the number of transfers. The RAPTOR journey planning algorithm optimizes for two criteria: arrival time and number of transfers. However, when optimizing for the minimal arrival time, RAPTOR doesn't maximize the departure time, neither it finds any later alternatives. Both properties are important for the end user satisfaction with a journey planner. Skipping in time to obtain the next alternative journey can degrade or significantly slow down the algorithm. In this paper we are analyzing model situations and impact of two approaches. Firstly, cycle management of general RAPTOR, and secondly, specific setting of RAPTOR's extension - rRAPTOR - which leads to provisioning set of journeys within a time range having minimal travel time for given number of transfers. The resulting journey planner is already used in public transit routing systems in the Czech Republic. We still receive customer complaints on the amount and variability of alternative journeys provided, however the complaint rate is steadily very low, around 1 complaint raised per quarter.