Competition between shared autonomous vehicles and public transit: A case study in Singapore

• Main Authors: Mo, Baichuan, Cao, Zhejing, Zhang, Hongmou, Shen, Yu, Zhao, Jinhua
• Format: Journal Article
• Language: English
• Published: 21-02-2021
• Subjects: Computer Science - Computer Science and Game Theory; Physics - Physics and Society; Quantitative Finance - Economics
• DOI: 10.48550/arxiv.2001.03197

Emerging autonomous vehicles (AV) can either supplement the public
transportation (PT) system or compete with it. This study examines the
competitive perspective where both AV and PT operators are profit-oriented with
dynamic adjustable supply strategies under five regulatory structures regarding
whether the AV operator is allowed to change the fleet size and whether the PT
operator is allowed to adjust headway. Four out of the five scenarios are
constrained competition while the other one focuses on unconstrained
competition to find the Nash Equilibrium. We evaluate the competition process
as well as the system performance from the standpoints of four stakeholders --
the AV operator, the PT operator, passengers, and the transport authority. We
also examine the impact of PT subsidies on the competition results including
both demand-based and supply-based subsidies. A heuristic algorithm is proposed
to update supply strategies for AV and PT based on the operators' historical
actions and profits. An agent-based simulation model is implemented in the
first-mile scenario in Tampines, Singapore. We find that the competition can
result in higher profits and higher system efficiency for both operators
compared to the status quo. After the supply updates, the PT services are
spatially concentrated to shorter routes feeding directly to the subway station
and temporally concentrated to peak hours. On average, the competition reduces
the travel time of passengers but increases their travel costs. Nonetheless,
the generalized travel cost is reduced when incorporating the value of time.
With respect to the system efficiency, the bus supply adjustment increases the
average vehicle load and reduces the total vehicle kilometer traveled measured
by the passenger car equivalent (PCE), while the AV supply adjustment does the
opposite.