Most people I see on their electric bikes aren't even pedaling. They're electric motorcycles, and they're a plague to everyone using pedestrian trails. Some of them are going nearly highway speeds, it's ridiculous.
There are 3 classes of e-bikes in the US, with class 3 topping out at 28mph—anything above that is illegal or in some weird legal grey area. You are thinking of e-motos which are an entirely different beast.
e-motos are a real problem; please don’t lump legitimate e-bikes in with those. It’s simply incorrect.
