A Video-based Study Comparing Communication Modalities between an Autonomous Car and a Pedestrian

There are increasing needs in communication between an autonomous car and a pedestrian. Some conceptual solutions have been proposed to solve this issue, such as using various communication modalities (eyes, smile, text, light and projector) on a car to communicate with pedestrians. However, there is no detailed study in comparing these communication modalities. In this study, we compare five modalities in a pedestrian street-crossing situation via a video experiment. The results show that a text is better than other modalities to express car's intention to pedestrians. In addition, we compare the modalities in different scenarios and environments as well as pedestrian's perception of the modalities.