Driving among autonomous vehicles: The effect of initial trust and driving style on driving behaviors

Although autonomous vehicles (AVs) are believed to reduce road accidents, they can be involved in accidents partly due to Conventional Vehicles (CVs) drivers' erroneous expectations that affect their risk-taking behaviors, such as following the AVs too closely and/or at an unsafe speed. In this article, the main objective is to propose a first exploratory study on how our expectations as drivers of conventional vehicles can shape our driving in the presence of autonomous vehicles. We investigated the role of initial trust in AVs on CV drivers' behaviors toward AVs. Ninety-five participants were confronted with trust-promoting or trust-lowering video clips of AVs driving. Individual driving behaviors were then assessed using a modified version of the Driving Behavior Questionnaire (DBQ) that distinguishes between lapses, errors, and ordinary and emotional violations. We also collected respondents' self-reported driving styles with the Multidimensional Driving Style Inventory (MDSI). The results showed that the trust-promoted group reported more deliberate ordinary and emotional violations than the trust-lowered group. These ordinary violations, due to their potential link to road accidents, highlight the importance of fostering realistic expectations about AVs. The emotional violations were not initially anticipated but were attributed to the unfamiliar and potentially frustrating behaviors exhibited by AVs. Finally, we emphasize the importance of trust calibration of road users toward autonomous vehicles to ensure road safety.