How encounter timing affects the impact of eHMI on surrounding drivers during automated truck merging

Automated driving has emerged as a potential solution to address the shortage of drivers in the logistics industry. For its implementation, it is crucial to ensure the acceptance of drivers surrounding automated vehicles. This study focused on examining how the external Human Machine Interface (eHMI) of automated trucks, along with the timing of encounters at highway junctions, can influence the driving behavior and acceptance of surrounding drivers. A driving simulator scenario was used to investigate visual behaviors, subjective evaluations, and driving performance when drivers encountered an automated truck at a highway junction. The findings suggest that the eHMI can positively influence safety by reducing the visual reaction time of surrounding drivers. However, depending on the timing of the encounter with the automated truck, the eHMI may potentially complicate avoidance decisions for surrounding drivers. Therefore, it is essential to carefully utilize the eHMI, considering the truck’s location at a merging area or its interaction with infrastructure facilities, to facilitate better decision-making for surrounding drivers.