>We’re talking about low speed, low risk, low property damage.

You realize that many of these are now being sold going 40-60mph ... that's not low speed, not low risk (many of them are built with wheels and brakes that are not safe for the speeds not to mention the cheap chinese batteries that catch on fire), nor low property damage when they hit things at top speed.

> exercise alone would have a positive impact in the U.S. that could very well offset the costs.

What exercise? The vast majority of these being sold aren't "pedal assisted" they are full electric sudo motorcycles.