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Transportation Research Part C
journal homepage: www.elsevier.com/locate/trc
Dynamic shared autonomous taxi system considering on-time
arrival reliability
Zhiguang Liu
a,
⁎
, Tomio Miwa
b
, Weiliang Zeng
c
, Michael G.H. Bell
d
,
Takayuki Morikawa
e
a
Department of Civil Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
b
Institute of Materials and Systems for Sustainability, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
c
School of Automation, Guangdong University of Technology, Guangzhou, Guangdong 510006, China
d
Institute of Transport and Logistics Studies, Business School, The University of Sydney, Sydney, NSW, Australia
e
Institute of Innovation for Future Society, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
ARTICLEINFO
Keywords:
Shared autonomous taxi system
On-time arrival reliability
Historical travel time information
System-beneficial path
Travel time
ABSTRACT
Dynamicsharedautonomoustaxi(SAT)systemsareregardedasapromisingmeansofimproving
travel flexibility. With no human drivers, SATs urgently require precise traffic information in
order to plan accurate paths independently; in addition, on-time arrival is an essential service
quality in SAT systems. In this study, taxis are assumed to be replaced with ride-sharing au-
tonomous vehicles. To improve the probability of on-time arrival, the reliable path concept and
collected travel time information are used to facilitate path finding for SATs, and the potential
benefitsareexamined.Twosimulationscenarios—onebasedonhistoricaltrafficinformationand
the other based on real-time traffic information—are executed to evaluate the information’s
usefulnessinreliablepathfinding.Insimulationresults,reliablepathscenariosshowedahigher
on-timearrivalratiothanshortestpathscenarios,inwhichtheshortestpathalgorithmisusedin
path finding for SATs, and the historical information-based scenarios showed a higher on-time
arrival ratio than the real-time information-based scenarios. A system-beneficial path finding
method is proposed and is verified to be effective for mitigating road network congestion.
1. Introduction
Autonomousvehicletechnologyhasexperiencedrapiddevelopmentinrecentyears(Caoetal.,2017).TheSocietyofAutomobile
Engineers (SAE) International defines five levels of autonomous driving, from driver assistance to full automation (SAE, 2016). To
date,manyvehicleshavefulfilledlevel1(driverassistance)and2(partialautomation),andseveralautomobilemanufacturesandIT
companies worldwide are now implementing level 4 (high automation) tests (Litman, 2018). A Singaporean technology company,
nuTonomy,usesautonomousvehiclesastaxiswithinanareaof2.5squaremiles(Patel,2016).Autonomousvehiclesareexpectedto
provide independent mobility for non-drivers, including disabled people and adolescents, while reducing transportation costs, en-
vironmental impacts, and congestion (Bansal et al., 2016). Autonomous vehicles can also support ridesharing services such as dy-
namicsharedautonomoustaxi(SAT)systems,inwhichautonomousvehiclesareusedassharedtaxis.BecauseSATscanservemore
thanonecustomer,theycanincreasetravelflexibility.CustomersrequestSATsviasmartphones,andSATsareassignedtocustomers
https://doi.org/10.1016/j.trc.2019.04.018
Received 18 May 2018; Received in revised form 17 April 2019; Accepted 17 April 2019
⁎
Corresponding author.
E-mail addresses: liu.zhiguang@i.mbox.nagoya-u.ac.jp (Z. Liu), miwa@nagoya-u.jp (T. Miwa), weiliangzeng@gdut.edu.cn (W. Zeng),
michael.bell@sydney.edu.au (M.G.H. Bell), morikawa@nagoya-u.jp (T. Morikawa).
Transportation Research Part C 103 (2019) 281–297
0968-090X/ © 2019 Elsevier Ltd. All rights reserved.
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