[Zak]

I've tested this. The fastest I could get a Voi scooter in Germany to go downhill was 27 km/h. They're limited to 20 km/h on level ground and gradually start braking if they exceed that speed downhill.

It might be possible to find a hill steep enough to overcome the braking force, or one that results in a strong enough braking force to make the scooter difficult to control, but it should be obvious to most people that attempting such a thing is dangerous.