I personally feel that the Movi is not really intended for these purposes but I have had many people ask me about this. I don't think it's really a safe idea unless I could set it up with some sort of vibration isolating device. Thoughts?
I've seen a few examples of vehicle mounts with photos in the forum. You should use some type of vibration dampening to mount the MoVI to otherwise bumps in the road could translate into the video.
We used some c stand arms, some furni pads, two beaver boards, and two cartalinis.. Check out my blog about the movi I have a pic there. http://www.t-rofilms.com/movi/