I used to have really bad motion sickness before puberty, pretty much throwing up or feeling constantly nauseous on nearly every car trip. It's much better now but I still get it sometimes.
When I used to frequently take a two-hour bus trip in the last 20 years I always had to sit in the most forward seat, and then I would still sometimes feel nauseous. It was especially bad if we were going around a long winding turn, and I found that it helped to keep staring at the same point on the bus windshield, so my eyes were not following the turn but staying fixed. I also found some relief from applying pressure to the inside of my wrist. This is a specific technique:
https://www.mskcc.org/cancer-care/patie ... d-vomitingNot having recently eaten also helped. And getting air. Buses sometimes have an small fan you can turn on in the console above the seat, and in a car you can either open the window or blow stronger (cool) air from the vent.
I can't read at all when I am in a car or bus, not even glancing down for a moment or it makes me feel queasy almost right away.
Is this related to ASD?
The buses I've been on have more vibration in back due to their engines being in back & perhaps that could be a factor for some people. I usually don't sit in back of buses but I haven't noticed feeling worse when I do but some people don't handle vibration as well. My girlfriend who's very likely also on the spectrum has never handled vibration well maybe due to nerve issues but she's usually not prone to motion sickness. She took the train trip with me & also took Meclizine & she was a little bothered on the way there. We saw my uncle briefly while we were down there & my uncle took some train trips when he was younger & recommended sitting in the middle of the car when we can. We had sat in back or front of the car on our way there(I forget which) & we sat in the middle on our way back & the ride was smother & Cass was bothered at lot less.