sustainability Article Sharing Anxiety is in the Driver’s Seat: Analyzing User Acceptance of Dynamic Ridepooling and Its Implications for Shared Autonomous Mobility Sigma Dolins 1,2,* , Helena Strömberg 2 , Yale Z. Wong 3 and MariAnne Karlsson 2 1 Mobility and Systems, RISE Research Institutes of Sweden, Lindholmspiren 3A, 41756 Göteborg, Sweden 2 Design & Human Factors, Chalmers University of Technology, 41296 Göteborg, Sweden; [email protected] (H.S.); [email protected] (M.K.) 3 Institute of Transport & Logistics Studies, University of Sydney Business School, Darlington, NSW 2006, Australia; [email protected] * Correspondence: [email protected] Abstract: As connected, electric, and autonomous vehicle (AV) services are developed for cities, the research is conclusive that the use of these services must be shared to achieve maximum efficiency. Yet, few agencies have prioritised designing an AV system that focuses on dynamic ridepooling, and there remains a gap in the understanding of what makes people willing to share their rides. However, in 2017, the Australian transport authority Transport for New South Wales launched over a dozen trials for on-demand, shared public transport, including AVs. In this paper, we investigate the user willingness-to-share, based on experiences from one of these trials. Four focus groups (19 participants in total) were held in New South Wales with active users of either the trialled on-demand dynamic Citation: Dolins, S.; Strömberg, H.; ridepooling service (Keoride) or commercial ridepooling (UberPool). Through thematic analysis Wong, Y.Z.; Karlsson, M. Sharing of the focus group conversations, the cost, comfort, convenience, safety, community culture, and Anxiety is in the Driver’s Seat: trust in authority emerged as factors that influenced the willingness-to-share. When presented Analyzing User Acceptance of with driverless scenarios, the focus group participants had significant concerns about the unknown Dynamic Ridepooling and Its behaviour of their co-passengers, revealing sharing anxiety as a significant barrier to the adoption Implications for Shared Autonomous of shared AVs. This paper identifies previously disregarded factors that influence the adoption Mobility. Sustainability 2021, 13, 7828. of AVs and dynamic ridepooling and offers insights on how potential users’ sharing anxiety can https://doi.org/10.3390/su13147828 be mitigated. Academic Editors: Margareta Friman, Lars Olsson and Hugo Guyader Keywords: shared mobility; dynamic ridepooling; autonomous public transport; on-demand trans- port; shared autonomous vehicles Received: 31 May 2021 Accepted: 30 June 2021 Published: 13 July 2021 1. Introduction Publisher’s Note: MDPI stays neutral Autonomous vehicles (AVs) have been presented by numerous manufacturers, trans- with regard to jurisdictional claims in port agencies, and city planners as a technology that promises to radically transform cities. published maps and institutional affil- AVs are, for example, argued to enable denser urban development (particularly in land ar- iations. eas that are traditionally used for parking), reduce the overall congestion on the roadways, and reduce fuel consumption and CO2 emissions [1]. In addition, AVs are contended to improve the quality and productivity of the time spent in-vehicle, increase the safety and efficiency of the transportation system, and transform transportation into a utility available Copyright: © 2021 by the authors. to anyone at anytime [2]. Licensee MDPI, Basel, Switzerland. Other suggested benefits of AVs are that they could increase the mobility of com- This article is an open access article muters and user groups that do not have driver’s licenses and, according to Becker and distributed under the terms and Axhausen [3] (p. 1294), “many who rely on public transport in remote areas, could be conditions of the Creative Commons offered independent and individual transport solutions”. While there are likely to be some Attribution (CC BY) license (https:// negative impacts, such as increased energy consumption due to repositioning, these have creativecommons.org/licenses/by/ been suggested as less significant and potentially mitigated if all future AVs are electric [4]. 4.0/). Sustainability 2021, 13, 7828. https://doi.org/10.3390/su13147828 https://www.mdpi.com/journal/sustainability Sustainability 2021, 13, 7828 2 of 22 Nevertheless, even with a fully electrified fleet, numerous studies indicate that the potential of AVs cannot be fully realized except through their use as purveyors of shared, pooled rides. In operating fleets of shared AVs, there are potentially system-wide ben- efits; an increase in vehicle occupancy is expected to reduce the number of cars needed to meet the travel needs of a given population, which could lead to moderating conges- tion and unlocking beneficial changes in urban form, such as decreasing the real estate devoted to standing parking and enable healthier pedestrian-focused spaces in urban environments [5–10]. Essentially, the development of fully self-driving cars is believed to solve many of the barriers associated with shared vehicle systems from both the provider and user perspectives, making it possible to respond better to service demands [1]. However, without established concepts or a use culture about how to share the asset of a vehicle, Fraedrich et al. [11] point to the likelihood that individuals will expect to use AVs like they use their privately-owned cars today. AVs as a private household good, and not a shared product, could lead to significant problems. If people accept to use AVs as a private household good, there is also the potential for a significant decrease in public transit ridership; already transportation networking companies (such as Uber) and ridehailing (the use of an mobile phone app to book a taxi service on-demand) have had a controversial effect on public transit, with some studies showing that there was a net reduction in transit use after the introduction of ridehailing services [12,13]. In order for public transit not to be negatively impacted by AVs, they will need to be shared; or better yet, part of the public transport offering. Without strong incentives for shared AVs (SAVs), single-occupancy, zero-occupancy, or privately owned AVs are at risk for increasing traffic congestion, encouraging urban sprawl, increasing energy consumption, and worsening socio-economic stratification at the personal level [14]. Therefore, it becomes crucial to examine the behaviours that would support “dynamic ridepooling”: matching ride requests so that multiple groups of passengers can be booked to the same vehicle in an efficient and environmentally-sound manner. By understanding how to encourage the acceptance of dynamic ridepooling, it would become easier to introduce SAVs as a public good or service, such as part of the public transport system. SAVs as public transport means that the individual person is burdened less with the financial needs of acquiring and maintaining personal transport or transport for family members, while still benefiting from door-to-door or nearly door-to-door convenience. SAVs as public transport could also mean safer transportation networks with fewer acci- dents and losses to the economy due to injury, property destruction, or death; these things contribute to the improved health and social well-being of citizens [15,16]. Nonetheless, any benefit of services based on shared AVs will only materialise if enough individuals are willing to adopt them. In our examination of previous work, we found that there was a knowledge gap in understanding the willingness-to-share dynamic ridepooling, and perhaps an overemphasis on investigating the technological acceptance of AVs. Aim The aim of the reported study was to contribute to more in-depth knowledge on factors impacting people’s willingness-to-share mobility journeys and trips, especially in a shared autonomous public transport context. We, therefore, applied a qualitative approach to address the following questions: • What factors (if any), beyond socio-economic factors, impact travellers’ willingness- to-share on-demand services? – What factors impact the willingness-to-share on-demand public transport? – Are these the same factors or different ones? • If the on-demand public transport vehicle is a shared AV, does the willingness-to-share the service of travellers change? Sustainability 2021, 13, 7828 3 of 22 2. Related Work Designing AVs to be a shared, on-demand product is believed to be key to transitioning into the widespread adoption of autonomous mobility and associated social benefits. We reviewed previous research into the factors that impact the willingness-to-share for contemporary ridehailed services, which could indicate the future willingness-to-use for AVs. In particular, we were interested in work that could build towards the acceptance of SAVs as part of the public transport system. According to Merat, Madigan, and Nordhoff [15] (p. 20), “there is potential for the mass-deployment of a new form of publicly available, electrically operated, ‘driverless’ vehicle for the urban environment, which can be adopted for sole or shared use and provide first mile/last mile transport”. In other words, AV technology could force the evolution of a new form of travel that offers the convenience, flexibility, and comfort of a private vehicle with public accessibility and ownership: communally-owned, SAVs as public transport [1]. In order to understand people’s willingness-to-share in human-driven,