External Human-Machine Interfaces Can Be Misleading: An Examination of Trust Development and Misuse in a CAVE-Based Pedestrian Simulation Environment.

Anees Ahamed Kaleefathullah,Jorge Garcia,Joost De Winter,Yee Mun Lee,Natasha Merat,Ruth Madigan,Yke Bauke Eisma

doi:10.1177/0018720820970751

Anees Ahamed Kaleefathullah, Jorge Garcia + Show 5 more

Open Access

https://doi.org/10.1177/0018720820970751

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Journal: Human factors	Publication Date: Nov 26, 2020
Citations: 49	License type: CC BY 4.0

Affiliation: Delft University of Technology, University of Leeds

Abstract

ObjectiveTo investigate pedestrians’ misuse of an automated vehicle (AV) equipped with an external human–machine interface (eHMI). Misuse occurs when a pedestrian enters the road because of uncritically following the eHMI’s message.BackgroundHuman factors research indicates that automation misuse is a concern. However, there is no consensus regarding misuse of eHMIs.MethodsSixty participants each experienced 50 crossing trials in a Cave Automatic Virtual Environment (CAVE) simulator. The three independent variables were as follows: (1) behavior of the approaching AV (within-subject: yielding at 33 or 43 m distance, no yielding), (2) eHMI presence (within-subject: eHMI on upon yielding, off), and (3) eHMI onset timing (between-subjects: eHMI turned on 1 s before or 1 s after the vehicle started to decelerate). Two failure trials were included where the eHMI turned on, yet the AV did not yield. Dependent measures were the moment of entering the road and perceived risk, comprehension, and trust.ResultsTrust was higher with eHMI than without, and the −1 Group crossed earlier than the +1 Group. In the failure trials, perceived risk increased to high levels, whereas trust and comprehension decreased. Thirty-five percent of the participants in the −1 and +1 Groups walked onto the road when the eHMI failed for the first time, but there were no significant differences between the two groups.ConclusioneHMIs that provide anticipatory information stimulate early crossing. eHMIs may cause people to over-rely on the eHMI and under-rely on the vehicle-intrinsic cues.ApplicationeHMI have adverse consequences, and education of eHMI capability is required.

Highlights

Pedestrian deaths constitute 16% of all traffic fatalities, and the vast majority of these crashes are due to human error (National Highway Traffic Safety Administration [NHTSA], 2019)
The results from this study clearly show that pedestrians are prone to misusing an external human–machine interface (eHMI) after repeated exposure to that eHMI
There is a risk that pedestrians will “blindly” follow-up the eHMI’s message and ignore the implicit communication of the automated vehicle (AV)

Summary

Introduction

Pedestrian deaths constitute 16% of all traffic fatalities, and the vast majority of these crashes are due to human error (National Highway Traffic Safety Administration [NHTSA], 2019). Automated vehicles (AVs) have the potential to improve road safety by excluding the human driver from the control loop (Fagnant & Kockelman, 2015). In current traffic, when pedestrians decide to cross the road in front of an approaching vehicle, they rely on both implicit and explicit cues. Implicit cues are regular vehicle behaviors, such as speed and deceleration. On the other hand, are not part of vehicle behavior, and include amongst others, eye contact, posture, and hand gestures of the driver (Sucha et al, 2017). One of the challenges in future AVs will be that the driver may be inattentive or even absent, which implies that explicit communication will become cumbersome or impossible. Human factors research indicates that automation misuse is a concern.

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