Well im usually the driver so that doesnt make me sick, but after ive been on a long bike ride i feel more in tune with my surroundings. In the car after a bike ride like that i feel every turn and acceleratiob. If i havent been biking sometimes i feel like im a couple steps behind the road in the car. So the driver in your case may be not as in tune feeling everything while you are. That could be part of it. Solution? You drive