Autonomous shuttle or conventional cab? Investigating users’ decision to share a ride
Authors: Biermann Hannah , Luca Liehner Gian , Philipsen Ralf , Ziefle Martina 
Published: June 2023

Private motorized transport poses a major challenge for traffic and the environment. Shared mobility might increase traffic efficiency and reduce traffic-related environmental pollution. The use of autonomous shuttles is conceivable for the future, opening further opportunities, e.g., road safety. From the user's point of view, not having their own vehicle can mean a loss of flexibility. Skepticism may arise, e.g., regarding the reliability of a service provider. Research is needed on the general willingness to share a ride, considering individual motivations for or against shared mobility. Regarding autonomous shuttles, there are gaps in knowledge about the extent to which the lack of a human driver on board affects trust and the willingness to use them compared to conventional driving services.MethodWe designed a two-step empirical research approach. Our aims were to investigate 1.perceptions of autonomous shuttles compared to conventional cabs in terms of safety and reliability,2.trust towards and intention to use autonomous shuttles,3.decisions to use an autonomous shuttle or a conventional cab, considering human factors (e.g., personality traits, mobility behavior).In a preliminary qualitative study, guided interviews (language: German) were conducted to explore reasons behind people' s choice to share a ride and to identify factors that influence their well-being and trust. To evaluate how differences in the level of automation might affect attitudes, conventional cabs and autonomous shuttles (both on-demand mobility services) were compared. In sum, 17 adults of different age groups (19 to 58 years) participated. The interviews were transcribed verbatim and analyzed using content analysis. Results were operationalized and measured in an online questionnaire survey (N=182). ResultsIn general, passengers' feeling of safety is relevant for their decision to share a ride. However, safety is perceived and evaluated differently regarding different means of transport. In a conventional cab, safety perception is enhanced by a human driver, especially in emergencies. In the case of autonomous shuttles, road safety is the key in achieving a high sense of security, since it is assumed that the autonomous shuttle, unlike cab drivers, always adheres to the applicable traffic regulations. Participants would prefer a ride in the autonomous shuttle to a cab ride and indicate a high willingness to use it for people other than themselves. For children or care-dependent people, special booking options, e.g., on board-monitoring, are requested. The general willingness to share a ride seems to depend on the perceived importance of car ownership.OutlookOur results contribute to a deeper understanding of attitudes towards novel mobility services. Results clarify which factors determine the general willingness to use shared mobility and which are specific to new and autonomous driving services. They also strengthen the knowledge of predictors for technology trust and acceptance in this context. The practical relevance of our study lies in the possibility to derive design and action recommendations for the user-centred development of autonomous shuttles considering individual needs and demands of different target groups.