Evaluating Multimodal Communication Methods for Autonomous Buses in Pedestrian-Dense University Environments

Abstract

In urban pedestrian zones where autonomous vehicles (AVs) increasingly operate alongside humans, clear communication between AVs and pedestrians is essential for safety and trust. This study conducted an exploratory research on pedestrian reactions to an autonomous shuttle bus (AutoBus) operating on a university campus. Using a real-world deployment, the effectiveness of visual and auditory communication cues in a real-world setting was evaluated. The AutoBus continuously looped a 480-meter path on campus during lunchtime, and pedestrians who walked toward and crossed the bus were invited to complete an online survey following this interaction. Data was collected from 58 participants at a technical university through behavioral observations and post-interaction surveys. The results reveal that visual cues were more consistently recognized than auditory ones, influencing pedestrian awareness and response. Trust in AV's safety was shaped more by its perceived safety than by prior experiences with the AutoBus. Moreover, willingness to yield was positively associated with the perceived social status of the AV, but not whether it was perceived as an autonomous robot or as representing its passengers. These findings offer practical insights for improving AV communication design to support safer, more intuitive interactions in shared spaces.