You can use anything you want...
Just remember that it's likely narrower than a car's interrior....
Measure the hell out of it then travel with tame peasure and see what's out there for you.
Keep track of the measurements and car's they fit and type of seats ETC... and post a nice Tech Article about it

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My fellow Americans, I have not been entirely truthful with you. I did gagoogity that girl. I gashmoigitied her gaflavity with my googis. And I am sorry.