Car sickness tends to happen when you're focusing on the interior of the car. That's what leads to the disconnect between your visual field and your mechanical sense of motion. I expect this is the main reason that drivers are rarely affected -- they're always looking out the window (more or less), so their visual sense of motion remains aligned with their other senses.
In my personal experience, car sickness is caused by high jerk (http://en.wikipedia.org/wiki/Jerk_%28physics%29), primarily during deceleration. (This is also commonly known as "bad driving".) I imagine this is something that self-driving cars won't have a problem with.
Seconded. I can take road trips like crazy, but hop in the Mountain View Caltrain shuttles with their crap drivers on a warm day, and I seriously feel like I could lose my lunch.
That doesn't necessarily account for people getting car sick on long, smooth, winding canyon roads driven at constant speed. The jerk induced by following the curves in the road should be lower than that caused by braking.
Honestly I think it is a combination of where your awareness is focused, and jerk. Long windy roads put varying lateral forces on passengers which probably become an issue if their focus is in the car.
Sometimes I get "carsick" while working with very small components (such as eyeglass-sized screws) that aren't behaving as they should, so I would have to attribute greater weight to the idea that carsickness is caused by a disagreement between the senses.
Well, at least in my case, it only happens as a passenger. I can sit there, and I'm fine, but the instant I try to read something, watch a video, or something like that, I start to feel bad.
Actually, even a glance at my GPS while driving wil occasionally cause a twinge.
I don't necessarily think that will be the case. As far as I knew (and from re-skimming the wiki article), car sickness (and any kind of motion sickness) is caused by the brain seeing different things than what it's processing from the inner ear. http://en.wikipedia.org/wiki/Motion_sickness
So it's more up to the individual in question, then the driver (considering a normal, average car ride, not anything in the extremes).
Maybe if you had some sort of AR setup that projected what you were interested in onto the environment. E.g., passengers would be able to read a book as if it was on a billboard floating on the horizon. Would that be enough to combat the effect?
In theory, yes. Motion sickness depends on the type of motion. A very bouncy or aggressive ride will result in more sickness, whereas a very smooth ride (such as a train) results in less. It's all about how much confusion there is between what you're seeing and your sense of balance.
As it happens, the same types of driving that are more fuel efficient cause less motion sickness. Still, driving anywhere with stop lights and other traffic probably necessitates enough stopping and starting that even maximally efficient driving software would cause motion sickness in many people.
I've always worn glasses but my vision has gotten progressively worse as I've aged - it's not bad, even now, I can legally drive without glasses - but it's enough to be noticeable.
I also was much less prone to motion sickness when I was younger - I would happily read full novels while riding along as a grade schooler.
My eyes have been awful since I was a kid, but just near-sighted. My daughter needed vision therapy as a young child, and when I went into the therapist's office, I got an exam for my glasses prescription.
Turned out that I had similar issues, just not noticeable. It had to do with my eyes not being able to properly maintain a focus at a specific distance over time, and their ability to track properly. I've always been a slow reader - this is at least partly why. I was told that it's also responsible for the fact that I get car sick within seconds of reading in the car, and that it goes away with therapy. Unfortunately, I never did go through with the therapy.
