Toward a Holistic Communication Approach to an Automated Vehicle's Communication With Pedestrians: Combining Vehicle...

Area of Science:

• Human-computer interaction
• Robotics
• Transportation engineering

Background:

• Automated vehicles (AVs) require effective communication strategies for safe interaction with pedestrians, especially vulnerable road users.
• Existing research inadequately addresses the interplay between vehicle kinematics and external human-machine interfaces (eHMIs) for pedestrian-AV interactions, particularly concerning different AV sizes.

Purpose of the Study:

• To investigate how the interplay of vehicle kinematics and eHMI influences pedestrians' willingness to cross, trust, and perceived safety when interacting with differently sized AVs.
• To evaluate the impact of dynamic versus static eHMIs and matching versus non-matching communication signals on pedestrian behavior and perception.

Main Methods:

• An online experimental study with 149 participants interacting with smaller and larger AVs in a shared space.
• AVs featured a 360° LED light-band eHMI with three statuses (none, static, dynamic) and varied kinematics (yielding vs. non-yielding).
• Included 'non-matching' conditions where dynamic eHMI intent contradicted actual vehicle movement.

Main Results:

• Pedestrians showed a significantly higher willingness to cross with the smaller AV compared to the larger AV.
• A dynamic eHMI enhanced perceived safety when the AV yielded.
• Even when the AV did not yield, a dynamic eHMI improved perceived safety over static or no eHMI.

Conclusions:

• The size of an automated vehicle significantly impacts pedestrian willingness to cross.
• Dynamic eHMIs can enhance perceived safety, but their effectiveness is contingent on matching the vehicle's actual kinematics.
• Mismatched communication signals from eHMIs can have negative consequences, highlighting the need for holistic and accurate AV communication strategies.