Cognitive distraction effect from non-driving related task engagement on automated vehicle occupants' motion sickness levels.

The promise of vehicle automation technology should allow occupants to utilize their time inside vehicles without becoming motion sick. Investigating this topic requires a safe replicable induction method that aligns with real-world driving dynamics. How engagement in non-driving related tasks contribute towards occupants' motion sickness levels also needs to be studied. The current within-subjects study investigated fully automated unprovocative and provocative driving conditions with and without an NDRT using a motion-based driving simulator. Results showed provocative driving led to higher motion sickness, owing to larger lateral and longitudinal accelerations. NDRT engagement in unprovocative driving led to higher motion sickness due to the extent of sensory conflict experienced, whereas in provocative driving, cognitive distraction from the NDRT limited motion sickness. Based on the findings, the Cognitive Distraction Effect is proposed to explain how NDRT engagement and the associated cognitive distraction effects the extent of motion sickness experienced under different driving conditions.