My MQ 3 refuses to work in the passenger seat in a moving car, it pops up a dialog box that says tracking has failed, maybe you can tell it to run without tracking but I never managed to hit the button. I saw a video where somebody has the same thing happen on the NY subway with an AVP.

For spatial computing to really work properly in a vehicle I think you need to keep track of both the world coordinate system and one that tracks the vehicle. In particular a lot of info from the IMU will have to be thrown out. It is probably useful to track small head motions but objects will drift eventually because of the vehicle as a whole accelerating and decelerating.