Improving Takeover Requests in Automated Vehicles: The Role of Dynamic Alerts and Cognitive State

Effective driver re-engagement is essential for the safe operation of automated driving systems (ADS), especially during takeover requests. This study examines the effects of alert intensity and driver engagement in non-driving related tasks on takeover performance in automated vehicles. Forty-one participants navigated simulated driving scenarios with various hazards and alert conditions, allowing analysis of response times, physiological responses, and subjective perceptions. The findings showed that higher-intensity alerts significantly reduced reaction times, leading to quicker driver takeovers. Interestingly, engagement in certain secondary tasks sometimes improved driver responsiveness, suggesting that moderate cognitive engagement may enhance alertness. Response times varied across different driving scenarios, indicating the influence of situational context on driver behavior. Physiological measures, including eye-tracking and heart rate monitoring, showed increased cognitive and physiological arousal during takeover events, particularly in response to stronger alerts. Participants reported higher confidence and satisfaction with high-intensity alerts, without reporting increased annoyance, indicating a preference for more assertive alert mechanisms. These outcomes highlight the critical role of adaptive alert mechanisms in ADS design, promoting for context-aware signaling and real-time driver state monitoring to improve takeover performance and ensure vehicular safety. The study suggests that future ADS should integrate dynamic alert systems capable of adjusting intensity based on situational urgency and driver engagement, thereby enhancing overall system reliability and user acceptance.