Investigating the Interplay between eHMI and dHMI for Automated Buses: How Do Contradictory Signals Influence a Pedestrian's Willingness to Cross?

Lau, Merle; Jipp, Meike; Oehl, Michael

doi:10.1145/3473682.3480284

Cited by 8 publications

(8 citation statements)

References 14 publications

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“…In online video-based surveys, Refs. [101][102][103][104] used similar light-based eHMIs to investigate pedestrians' interactions with differently sized AVs. The eHMIs indicated differing combinations of the vehicle's automation status (VAS), the vehicle's intention, and the vehicle's perception (VAS + intention, VAS + perception, and VAS + intention + perception).…”

Section: Resultsmentioning

confidence: 99%

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External Human–Machine Interfaces for Automated Vehicles in Shared Spaces: A Review of the Human–Computer Interaction Literature

Brill

Payre

Debnath

et al. 2023

Sensors

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Given the rise of automated vehicles from an engineering and technical perspective, there has been increased research interest concerning the Human and Computer Interactions (HCI) between vulnerable road users (VRUs, such as cyclists and pedestrians) and automated vehicles. As with all HCI challenges, clear communication and a common understanding—in this application of shared road usage—is critical in order to reduce conflicts and crashes between the VRUs and automated vehicles. In an effort to solve this communication challenge, various external human–machine interface (eHMI) solutions have been developed and tested across the world. This paper presents a timely critical review of the literature on the communication between automated vehicles and VRUs in shared spaces. Recent developments will be explored and studies analyzing their effectiveness will be presented, including the innovative use of Virtual Reality (VR) for user assessments. This paper provides insight into several gaps in the eHMI literature and directions for future research, including the need to further research eHMI effects on cyclists, investigate the negative effects of eHMIs, and address the technical challenges of eHMI implementation. Furthermore, it has been underlined that there is a lack of research into the use of eHMIs in shared spaces, where the communication and interaction needs differ from conventional roads.

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Section: Resultsmentioning

confidence: 99%

“…While the majority of the reviewed papers utilized video-based surveys to evaluate their eHMI concepts, a few [101][102][103][104] utilized VR or field-based testing. As previously discussed, while questionnaires are a good first step in the evaluation, they often do not reflect real-world behavior due to the lack of ecological validity.…”

Section: Methodsmentioning

confidence: 99%

External Human–Machine Interfaces for Automated Vehicles in Shared Spaces: A Review of the Human–Computer Interaction Literature

Brill

Payre

Debnath

et al. 2023

Sensors

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show abstract

“…This study aims to investigate pedestrians' interaction with two differently sized AVs (smaller AV vs. larger AV) focusing on the interplay of eHMI status (no eHMI vs. static eHMI vs. dynamic eHMI) and vehicle kinematics (yielding vs. non-yielding) on a shared space. Very preliminary results of this study have been already published (Lau et al, 2021b).…”

Section: Research Aim and Hypothesesmentioning

confidence: 87%

Toward a Holistic Communication Approach to an Automated Vehicle's Communication With Pedestrians: Combining Vehicle Kinematics With External Human-Machine Interfaces for Differently Sized Automated Vehicles

2022

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Future automated vehicles (AVs) of different sizes will share the same space with other road users, e. g., pedestrians. For a safe interaction, successful communication needs to be ensured, in particular, with vulnerable road users, such as pedestrians. Two possible communication means exist for AVs: vehicle kinematics for implicit communication and external human-machine interfaces (eHMIs) for explicit communication. However, the exact interplay is not sufficiently studied yet for pedestrians' interactions with AVs. Additionally, very few other studies focused on the interplay of vehicle kinematics and eHMI for pedestrians' interaction with differently sized AVs, although the precise coordination is decisive to support the communication with pedestrians. Therefore, this study focused on how the interplay of vehicle kinematics and eHMI affects pedestrians' willingness to cross, trust and perceived safety for the interaction with two differently sized AVs (smaller AV vs. larger AV). In this experimental online study (N = 149), the participants interacted with the AVs in a shared space. Both AVs were equipped with a 360° LED light-band eHMI attached to the outer vehicle body. Three eHMI statuses (no eHMI, static eHMI, and dynamic eHMI) were displayed. The vehicle kinematics were varied at two levels (non-yielding vs. yielding). Moreover, “non-matching” conditions were included for both AVs in which the dynamic eHMI falsely communicated a yielding intent although the vehicle did not yield. Overall, results showed that pedestrians' willingness to cross was significantly higher for the smaller AV compared to the larger AV. Regarding the interplay of vehicle kinematics and eHMI, results indicated that a dynamic eHMI increased pedestrians' perceived safety when the vehicle yielded. When the vehicle did not yield, pedestrians' perceived safety still increased for the dynamic eHMI compared to the static eHMI and no eHMI. The findings of this study demonstrated possible negative effects of eHMIs when they did not match the vehicle kinematics. Further implications for a holistic communication strategy for differently sized AVs will be discussed.

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“…Additionally, vehicles can transmit information explicitly to surrounding road users via conventional light signals (e.g., turn indicators) and novel concepts (e.g., light emitting concepts like a 360 • LED light-band), which is often referred to as external humanmachine interface (eHMI) (Bazilinskyy et al, 2019;Rouchitsas and Alm, 2019;Schieben et al, 2019Schieben et al, , 2020Dey et al, 2020;Lau et al, 2021b;Wilbrink et al, 2021). In today's traffic, at least in Germany drivers can indicate their initiated stopping maneuver by actuating their turn indicator (Färber, 2016).…”

Section: Visual External Communication Of Havs With Other Tra C Parti...mentioning

confidence: 99%

Promoting trust in HAVs of following manual drivers through implicit and explicit communication during minimal risk maneuvers

Hess

Lau

Wilbrink

et al. 2023

Front. Comput. Sci.

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The successful integration of highly automated vehicles (HAV) in future mixed traffic environments will depend, among other things, on their seamless, safe, and accepted interaction with other road users. Therefore, appropriate combination of light signals, as external human-machine interface (eHMI), and driving behavior, as dynamic human-machine interface (dHMI), is required consistently in order to develop trust of following manual drivers in HAVs. Especially, in borderline traffic scenarios where HAVs are confronted with challenges, such as loss of connectivity, so-called minimal risk maneuvers (MRMs) are performed abruptly. Here, understanding communication via eHMI and dHMI is crucial for road safety, as drivers need to prepare for maneuvers themselves. Therefore, two consecutive, explorative online video studies were conducted. Firstly, the appropriate braking dynamics for an MRM were evaluated. Secondly, insights into the eHMI communication strategy of an HAV during an MRM were gained. The overall aim of this work is to present strategies for implicit and explicit communication channels of an HAV in order to promote learned trust during MRMs from the perspective of drivers who follow them. The results show that adding novel eHMI designs (e.g., warning sign, 360° LED light-band) to conventional light signals positively affects the user experience in a first contact interaction. The findings could have a positive impact on the development of trust in HAVs. In conclusion, specific eHMI communication strategies can be highly supportive for following manual drivers in MRM scenarios, which may lead to legislative considerations in the future.

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Investigating the Interplay between eHMI and dHMI for Automated Buses: How Do Contradictory Signals Influence a Pedestrian's Willingness to Cross?

Cited by 8 publications

References 14 publications

External Human–Machine Interfaces for Automated Vehicles in Shared Spaces: A Review of the Human–Computer Interaction Literature

External Human–Machine Interfaces for Automated Vehicles in Shared Spaces: A Review of the Human–Computer Interaction Literature

Toward a Holistic Communication Approach to an Automated Vehicle's Communication With Pedestrians: Combining Vehicle Kinematics With External Human-Machine Interfaces for Differently Sized Automated Vehicles

Promoting trust in HAVs of following manual drivers through implicit and explicit communication during minimal risk maneuvers

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