Asking the Wizard-of-Oz: How experiencing autonomous buses affects preferences towards their use for feeder trips in public transport

Autonomous vehicles are expected to have a significant impact on the entire transport sector. With respect to public transportation, autonomous buses—as a means of small and flexible on-demand services—have the potential of increasing the accessibility of people and lower operational costs. As such services are not currently available, their acceptance by their prospective riders and their potential to boost public transportation are yet to be identified. The present study aims at shedding light on these issues by combining a Wizard-of-Oz experiment with a two-stage stated preference (SP) study. The participants of the study had the opportunity to try an ostensible autonomous bus, in the form of a feeder service, over a period of two to four weeks (Wizard-of-Oz experiment). Furthermore, they were confronted with the same hypothetical mode choice tasks, including two autonomous bus alternatives (SP experiment), before and after the Wizard-of-Oz experiment. The study took place in two cities in Germany, namely Berlin and Braunschweig. In this paper, we analyze the mode choices of the pooled sample of participants using a Mixed Logit model with random parameters in order to tackle respondents' heterogeneity of preferences. By estimating the model using the answers from the before and after experiments, we show that there is a positive effect in favor of the autonomous bus service for the feeder trip. In line with the expectations, the results indicate that the participants of the study have a preference for being the only passenger in the vehicle, while they prefer to call it just before their departure, rather than reserving it beforehand.