Implementation and Evaluation of an On-Demand Bus System
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Implementation and Evaluation of an On-demand Bus System Sevket Gokay¨ 1,2, Andreas Heuvels1, Robin Rogner1 and Karl-Heinz Krempels1,2 1Informatik 5 (Information Systems), RWTH Aachen University, Aachen, Germany 2CSCW Mobility, Fraunhofer FIT, Aachen, Germany Keywords: Demand-responsive Transport, Dynamic Pickup and Delivery Problem, Vehicle Routing Problem with Time Windows. Abstract: This work aims to develop and evaluate a dynamic bus system which abandons the concepts of a traditional bus service like bus line, bus station and timetable. The resulting system supports bringing customers from any location to any location, has a fleet of buses the routes of which are updated repeatedly as requests arrive and are accepted, and employs time windows in order to guarantee the desired pick-up and drop-off times of customers. We propose a technical realization and evaluate its effectiveness by running simulations in which traditional and dynamic systems are compared. Even though the operational cost and financial efficiency from a bus service provider’s perspective is not the focus of this evaluation, the preliminary results show that both the provider and the customers might benefit from an on-demand dynamic system. We also hint at the feasibility of such a system in not only low-demand rural areas, but also high-demand urban regions. 1 INTRODUCTION of service operation results in buses having dynamic routes. We denote the system as online full on-demand With the ever-improving technology landscape, tradi- riding system, in which requests are processed in real tional and existing systems are challenged with new time during service time (online – as opposed to off- ideas that aim for optimization by making them more line on-demand systems which collect requests be- intelligent. Transportation systems have always been fore service, calculate a schedule which is fixed af- such a target and more specifically, public transporta- terwards during the operation of the vehicle) and ar- tion benefited immensely from advancements in IT bitrary coordinates are used for pick-up/drop-off (full and mobile Internet becoming more widespread. The – as opposed to semi on-demand systems which func- operation of public transport bus services currently tion based on fixed stations or locations). bases on buses traveling along fixed routes visiting predefined bus stops according to a fixed timetable. This is the product of efforts in public transportation Motivation planning where many factors of all stakeholders are 1 taken into account in order to find an optimal solu- The aim of the project Mobility Broker was to inte- tion covering the majority of the needs. Naturally, the grate multiple mobility services (e. g. bus, train, car- sharing, bike-sharing) into one platform using stan- main focus is on urban areas where a high demand 2 for transportation exists. However, in less populated dardized communication interfaces, i. e. IXSI . The rural areas the service offerings are inferior and bus platform becomes the one stop shop for the mobility transportation should be adapted to their special re- needs of its customers. This way customers have to quirements. interface with only one entity when planning an inter- modal itinerary and can book one combined ticket in- This work addresses the issue of fixed routes and stead of multiple mode-specific tickets (Beutel et al., bus stops by proposing a system in which the passen- 2014). It was, therefore, essential that the platform gers put requests to the service to be picked up from supports intermodal routing taking all integrated ser- any location to travel to any location within the ser- vices into account (Beutel et al., 2016). vice area. Subsequently, the service finds a bus in operation (from a list of buses), assigns the request to 1https://mobility-broker.com/ the bus and updates the route of the bus. This kind 2Interface for X-Sharing Information (Kluth et al., 2015) 217 Gökay, S., Heuvels, A., Rogner, R. and Krempels, K-H. Implementation and Evaluation of an On-Demand Bus System. DOI: 10.5220/0006300102170227 In Proceedings of the 3rd International Conference on Vehicle Technology and Intelligent Transport Systems (VEHITS 2017), pages 217-227 ISBN: 978-989-758-242-4 Copyright © 2017 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved VEHITS 2017 - 3rd International Conference on Vehicle Technology and Intelligent Transport Systems During the analysis of status quo of mobility ser- heuristic algorithms can be found in scientific liter- vice offerings it was realized that low population den- ature. In (Savelsbergh and Sol, 1995) the authors sity – rural – areas suffer from three shortcomings: present the general problem of pickup and delivery, its varying forms (DARP being one of them), the char- 1. There are only a small number of mobility ser- acteristics and solution approaches. An overview of vices being offered: Most service providers con- models and algorithms can be found in (Cordeau and centrate on urban regions, leaving rural areas out Laporte, 2007) and (Desaulniers et al., 2001). These of their coverage plan (e. g. car-sharing). works also unveil subcategories of DARP: Offline and 2. Low service quality of existing services compared online, single-vehicle or multi-vehicle, without time to urban regions: Considering the example of bus constraints or with time windows. In this context, a services, they mostly have less stations (i. e. sta- more focused overview, i. e. an overview of vehicle tions are more distant from each other) and the routing with time windows, is given in (El-Sherbeny, buses are driving less frequently (i. e. increased 2010). waiting periods). An optimization method for improving or design- 3. Rural areas can be sparsely connected to urban ar- ing a traditional bus network for a small- or medium- eas (or town centers). sized town has been proposed in (Amoroso et al., 2010). The authors present a modeling framework These lead to bad customer experience which we with an iterative approach to improve existing bus wanted to challenge: Is it possible to provide an alter- lines in order to maximize an objective function. The native, better service in rural areas and how can it be objective function takes user demand as well as op- realized? How can we integrate this service into Mo- eration cost of the network into account. The work bility Broker, making the journeys between rural and in (Crainic et al., 2010) deals with the design of a urban areas seamless? Can the system be deployed in master schedule for a demand-adaptive transit system urban areas as well? In urban areas, can the system (DAS), which is a hybrid between traditional bus ser- match or even surpass the quality of service of the vice and an on-demand system usually offered in low traditional services (e. g. in peak hours)? And on a re- demand transportation areas. The proposal employs a lated note, would the system be only a supplement to set of mandatory stops with corresponding time win- existing offerings or could it replace existing services dows and optional stops which are inserted by pas- in urban areas? sengers. An on-demand bus system which highly The remainder of this paper is structured as fol- influenced the system proposed by this work is pre- lows: Section 2 lists related research and existing ap- sented in (Tsubouchi et al., 2010). However, unlike plications in the field of interest. Consequently, the this work, the presented system uses predefined bus taken iterative approach is explained in Section 3. stops. The system leverages cloud computing to lower Section 4 presents the tools and details of technical operational costs and computation time. A simulation realization. It is followed by Section 5 that illustrates and field tests in multiple cities yield promising re- the evaluation methodology and results. Finally, Sec- sults and the authors conclude that, with their heuris- tion 6 concludes the paper. tic, the calculation time does not increase exponen- tially. In (Martinez et al., 2006) the authors propose an online on-demand shuttle system for the University of Maryland College Park, that continues to use exist- 2 RELATED WORK ing bus stations. For evaluation, the authors compared the results of simulations of their and existing shuttle This section gives a general impression of related systems. It was concluded that their approach per- work done in the field of interest. forms slightly better than the existing system. Nev- Demand Responsive Transport (DRT) is the um- ertheless, it lacks the usage of time windows, so that brella term to describe and categorize the efforts to arrival times cannot be predicted or guaranteed. The develop transportation services based on demand. In authors of (Mukai and Watanabe, 2005) test different particular, the underlying problem is known as the on-demand transportation services, which they cate- Dial-A-Ride Problem (DARP). DARP aims to find gorize in semi- and full-demand systems. The fea- vehicle routes and schedules for k customers where sibility and realization of a DRT service for a low- each customer defines the pickup and delivery loca- demand density area is examined in (Li et al., 2007). tion, and the pickup or delivery time. DARP gen- A model to investigate the financial viability of a DRT eralizes the Traveling Salesman Problem (TSP) and system is presented in (Ronald et al., 2013). is therefore NP-hard (Gørtz, 2006). Due to the need in practical applications and its NP-hardness, many 218 Implementation and Evaluation of an On-Demand Bus