Development of eHMI Design Factors from the Perspective of Road Users: A Systematic Literature Review

Objective: The aim of this study is to present eHMI design factors for effective communication between autonomous vehicles and various road users.<br/>Background: With the advent of smart cities and the acceleration of research on selfdriving vehicles, eHMI also needs application standards for commercialization, and current studies have mixed results on effectiveness to consider in actual eHMI design, and there are no clear design standards as eHMI are newly emerging vehicle devices. <br/>Method: A systematic review method was applied to present integrated eHMI design standards, and 48 literatures related to eHMI research considering ergonomic aspects were selected and analyzed.<br/>Results: It presents eight design factors (Placement, Distance, Vehicle Scale, Message, Color, Modality, System Mode, Information Mode) that eHMI should consider and includes explicit guidance in each criterion.<br/>Conclusion: By presenting integrated ergonomic results beyond the technical point of view of a vehicle-to-person communication tool called eHMI, it is possible to present standards for eHMI design that consider the effectiveness of existing mechanical characteristics as well as the impact on road users.<br/>Application: This study established design factors based on the characteristics of eHMI and can be used as basic data for eHMI applicable to actual development.