Assessing Cognitive Workload and Driver Performance: A Comparative Study of Pneumatic and Vibrotactile Haptic Alerts for Takeover Requests in Autonomous Vehicles

This study explores the effectiveness of pneumatic and vibrotactile haptic feedback modalities on a steering wheel in improving driver response times and accuracy during Take-Over Requests (TOR) in Level 3 autonomous vehicles. Dual-modal feedback, combined with audio cues, was tested across nine TOR tasks to assess its impact on driver performance. Results show that combining audio with either feedback type significantly improved TOR performance compared to audio alone. Pneumatic feedback, offering a gentler and more naturalistic alert, enabled smoother transitions and reduced stress, while vibrotactile feedback, being more mechanical, may be better suited for high-urgency scenarios. Cognitive workload, measured using NASA-TLX scores, revealed that pneumatic feedback reduced mental demand and frustration more effectively than vibrotactile feedback. These findings suggest pneumatic feedback may be more comfortable for prolonged alerts, while vibrotactile feedback may be preferable in urgent situations. Further research could optimize adaptive feedback systems based on driving conditions.