Motion sickness is mostly caused by your brain trying to resolve opposing signals between your eyes and your sense of motion. If you're looking at a non-moving scene like a screen in the car, but everything else in your body says you're moving at 60 MPH, you might get motion sickness.
A gimbal-mounted seat would change how often you bumped around, but your vestibular system would still sense things like going up/down a hill or making a turn.
Basically, a gimbal-mounted seat would be about as effective as a perfectly paved road.
Motion sickness is mostly caused by your brain trying to resolve opposing signals between your eyes and your sense of motion. If you're looking at a non-moving scene like a screen in the car, but everything else in your body says you're moving at 60 MPH, you might get motion sickness.
A gimbal-mounted seat would change how often you bumped around, but your vestibular system would still sense things like going up/down a hill or making a turn.
Basically, a gimbal-mounted seat would be about as effective as a perfectly paved road.