Research and/or engineering questions / objective AEBS (Advanced Emergency Braking System), which is increasingly being installed in vehicles, is expected to help reduce accidents. However, it cannot prevent collisions with vehicles merging from side roads, which are a common cause of accidents. Therefore, a method for addressing the limitations of AEBS is required. This study focused on preventing collisions between vehicles merging from side roads and those moving on highways. We designed an HMI (Human Machine Interface) that facilitates safe merging by informing both merging and highway vehicles and enabling message exchange between the two vehicles. Methodology We designed two types of HMI: HMIA, which uses road-to-vehicle communication, and HMIB, which uses vehicle-to-vehicle communication. HMIA notifies a highway vehicle of the presence of a merging vehicle ahead on the left and informs the merging vehicle of the best time to merge. HMIB enables message exchange between drivers to increase their sense of security. When a merging vehicle stops at a stop line, HMIB automatically sends a message from the merging vehicle to the highway vehicle requesting merging acceptance. The driver of the highway vehicle responds by pressing a button to confirm acceptance or rejection. After receiving the acceptance message, the merging vehicle merges. Information transmission tools are voice guidance and HUD. Further, we verified the optimal activation timing for HMIA. For HMIB, ease of merging and an increased sense of security were verified by comparing with HMIA. In total, 60 subjects participated in this experiment. Results The experimental results indicated that HMIA is effective in promoting safe merging for both highway and merging vehicles when activated at least 10 seconds before a highway vehicle reaches the merge point. Earlier HMIA activation made drivers nervous (pupil area data), reducing the number of merging vehicles that could merge. Further, results related to HMIB showed that vehicle-to-vehicle communication facilitated the sense of security of the drivers of highway vehicles. It was also shown that after merging, the speed of the highway vehicles could be quickly restored. Using HMIB instead of HMIA increased the number of merging vehicles that could merge, enabling easy vehicle merging. Subjective data (questionnaire) suggested similar results to experimental data for both HMIA and HMIB. Limitations of this study For HMIA, the maximum acceptable timing of HMIA activation is not yet established. Therefore, it must be clarified. HMIB did not significantly increase the sense of security of the drivers of merging vehicles, presumably owing to the difficulty in understanding the HUD of merging vehicles and the HMIB activation timing being a little too early. Therefore, it is necessary to improve them. What does the paper offer that is new in the field including in comparison to other work by the authors ? Because AEBS cannot respond to vehicles merging from side roads, most studies on collision avoidance in the event of vehicles merging from side roads analyzed the behavior of drivers with regard to finding factors necessary for drivers themselves to avoid accidents. However, there are limits to human capabilities. Therefore, in this study, we designed an HMI that enables merging and main road vehicles to confirm each other's presence and intentions to establish safe conditions with low collision risks. Conclusion To avoid collisions between vehicles merging from side roads and highway vehicles, we designed an HMIA that alerts both vehicles to each other's presence and an HMIB that enables both vehicles to interact with each other. Further, we verified the appropriate timing of HMIA activation and the effectiveness of HMIB in increasing a sense of security among drivers. The results showed that HMIA is effective when activated at least 10 seconds before oncoming highway vehicles reach merging points. HMIB could increase the sense of security of highway drivers and make merging of vehicles easier.

Mr. Hikaru Kawada, Postgraduate student, Shibaura Institute of Technology