Just a quick pointer, there is no way to avoid motion sickness for humanity as a whole. There’s just tips and tricks in relation to what is considered a comfortable experience and an uncomfortable. Not to say that uncomfortable experiences are to be avoided (however at the current stage of the vr game it’s best to avoid due to the small population) as they tend to be the most immersive if done correctly. Now driving is tricky because motion sickness and driving is a problem that exsists in the real world as well.
Anyways to help you out with your question the more you artificially manipulate the camera the more likely you are to trigger motion sickness with people who are sensitive to it. Since this can’t be avoided since it’s a vehicle that is generating the locomotion your safest bet is to eliminate the Y-Axis from your track/world. It’s a little less immersive driving on a flat plane but it’s overall the most comfortable experience one can get from digitally driving.