Investigating impact of situation awareness-based displays of semi-autonomous driving in urgent situations

Semi-autonomous vehicles still require drivers to take over in an unexpected situation. In this situation, the increased cognitive load on the driver can lead to distraction, which in turn reduces situational awareness (SA) and prevents appropriate responses, increasing the risk of accidents. For this reason, providing interfaces that enhance SA is essential to ensuring safety and optimal performance. However, existing SA-based display research often overlooks the levels of SA and effectiveness of modalities, especially in urgent situations where a driver's SA might be compromised. The present study aims to design SA-based display that considers the urgency of the situation and the level of SA in line with a specific design framework and modality effectiveness. We conducted an experiment using simulated videos to evaluate the effectiveness of the SA-based display. This experiment assessed the effects of three urgent situations and three levels of situational awareness-based displays on drivers' SA, situational trust, mental workload, and perceived urgency. We employed a 3x4 mixed-factorial design for the experiment. The betweensubject factors were the SA levels (perception, comprehension, and projection) and a baseline. The within-subject factors were urgency scenarios (low, medium, and high). The results showed that as urgency increased, displays reflecting Level 3 SA, which requires prediction, significantly improved SA compared to other displays. We expect our findings to contribute to the practical design of automotive displays by providing useful considerations for SA-based display design.