if the top speed was over 30mph it was no longer classified as a scooter or moped it was a motorcycle. Engine size was limited to 50cc as well. Most are actually smaller, even though they call them a 50.
Every scooter I ever had topped out at 28-29, and the mopeds usually topped out at about 25.
Guy I knew had a weird scooter that looked like a skateboard with handlebars that the engine sat on the back. He spent close to $400 on hop-up parts for it, and it would still only go around 30 mph.