On-Road Motion Sickness Onset and Limited In-Vehicle Recovery Under Sustained Task Engagement

Automated vehicles may increase passenger engagement in visual tasks yet limited on-road data describe how quickly motion sickness develops or whether symptoms recover during travel. We analyzed motion sickness onset, accrual, and recovery in 109 adults seated as front passengers in an instrumented sedan during urban or highway routes. Participants completed no-task and handheld-device task sessions involving reading, visual search, and text entry. Motion sickness was reported at one-minute intervals using the 0–10 UMTRI Motion Sickness Scale. During task sessions, 58% of urban-route participants and 21% of highway-route participants reached a rating of 2 or higher, compared with 30% and 8% during no-task sessions. Ratings increased across drives, with limited sustained within-drive recovery; decreases of at least two points occurred in only 9% of urban and 4% of highway task sessions. These findings indicate that motion sickness is amplified by visually demanding device use and may persist once symptoms emerge.