I would imagine any Judge interpeting a motor vehicle as: If it has a motor attached to it and it assist in the propulsion while on a road or highway....then it's a motorized vehicle.
On the question of a motorized cart with one or two wheels, I've seen drawings in old Mechanics Illustrated Magazines from the 1930's where a small one wheel motor assist trailer was attached to the upper rear forks of the rear tire. Today I see something similar for a child to ride with it's own pedals etc that attaches to the bike mom rides in the same way.
But again in the 1930's there were so fewer people, laws, and law enforcement agencies that kids could do things in a bigger way without restriction. They may have had greater access to open spaces to test
and work on their projects or enjoy them as well.
On the question of a motorized cart with one or two wheels, I've seen drawings in old Mechanics Illustrated Magazines from the 1930's where a small one wheel motor assist trailer was attached to the upper rear forks of the rear tire. Today I see something similar for a child to ride with it's own pedals etc that attaches to the bike mom rides in the same way.
But again in the 1930's there were so fewer people, laws, and law enforcement agencies that kids could do things in a bigger way without restriction. They may have had greater access to open spaces to test
and work on their projects or enjoy them as well.