I don't know what the rules are behind the official county made signs at every access that read "No Motorized Vehicles."
But I do know it is situational common sense.
The loop is a Pedestrian use path as well as a bicycle path.
No Motor driven vehicles covers internal combustion motors and electric motors. no matter if they are on a go cart or bicycle or scooter.
The policy conforms with the general rules of the road with pedestrians getting the ultimate right of way.
The Loop is not a transportation avenue it is a recreation feature, there are more people walking on it than riding. Its plain dangerous for even the packs of wannabe race boys that scoot around the path faster than 15mph. Blind curves, dogs, leashes, cell phones. Semi-pro bike pilots, recreational cyclists and people teetering around counting calories and groups of ladies dressed brightly walking fast and only paying attention to the point they are trying to make in the discussion.
It only makes sense to keep high speed vehicles out of this mix.