For a few years now I really struggle in cars. From mild discomfort, to feeling really queasy, getting the sweats, have to focus on my breathing, open the windows and a couple of times I actually threw up. Either in the car or as soon as I got out.
I never had this issue as a child, even when all bundled up in the back like sardines, no seatbelts etc. In fact , in my late teens/20s one of my biggest pleasures was going on a long drive (as a passenger). I have no idea what changed. Some cars seem worse than others , for examples it’s more likely to happen in an uber than in our car , but it still happens. Coaches are hit and miss as well.
I’m still ok on aeroplanes and boats.