An investigation into trust between an SAV and its passengers

Abstract: As more and more shared autonomous vehicles (SAVs) are introduced in mixed traffic conditions, it calls upon research exploring the relationship between an SAV and its passengers. It is assumed that in the future SAVs will be completely autonomous, with no operator on-board, resulting in the loss of implicit communication between a driver and a passenger with effects on trust. This served as motivation to perform a study investigating the definition of trust from the passenger’s perspective. Initially a state-of-the-art study was conducted to research previous work and identify existing trust frameworks. Three field studies took place on an operational SAV which included interviews and observations with on-board operator and passengers. The aim of which was to understand the trust dynamics between the operator and passenger but more importantly, between the SAV and its passengers. The results revealed dependency on the operator during the commute in deadlock situations. To investigate trust attributes, interviews and observations were conducted with passengers of a regular bus as well as experts from the field of transportation. Situational awareness of the SAV and communication of SAV intention were deemed most important towards building trust with caution towards information overload. Furthermore, three participatory design studies conducted showed a multi-modal approach as the preferred way of communication, with visual and auditory modalities being the most favorable choice. The overall results showed that a communication and feedback channel with an SAV and its passengers is necessary in creating trust in the absence of a driver. Future studies could use the findings from this thesis as the building blocks for creating a communication interface to enhance passengers trust in an SAV.