Just wanted to continue the interesting discussion of legal definitions that came up elsewhere. This is purely a discussion about interesting legal matters, not at all a comment on anyone's rights or banning anyone from anywhere or allowing anyone anywhere or anything else. That's why it's down here in Off Topic, because it's just interesting stuff to some.
It had come up elsewhere, so here's more info on the legal definitions of motor vehicle as it applies to things like wheelchairs and mobility scooters.
Judging by these articles, a number from years ago, the definitions are often not clear. I'm still tracking down more recent findings.
For example, in these links there is discussion of whether to charge someone drunk in a motorized wheelchair or scooter with DUI...whether a license is needed for a scooter, and similar questions.
Pretty interesting, varying jurisdiction by jurisdiction, where I think many people assume it's universally defined.
Some stuff about Segways and 'electronic personal assistive mobility devices' here
Case about a heavily modified scooter here http://www.jud6.org/legalcommunity/legalpractice/opinions/appellatedivisionopinions/2005/03-5079AP-88B%20Cook.htm
DUI stuff here: http://hillsboroughdefense.com/wheelchair-dui/
More DUI: http://www.sptimes.com/2004/12/13/Hernando/Woman_s_DUI_case_ques.shtml
Note these are from Florida, as I was trying to locate the resolution of the earlier case I posted.