In the UK, as in Europe and Australia I believe, Ebikes ("pedelecs") are legally limited to assistance only up to 15mph=25kph (it's possible to exceed this downhill, of course). As someone used to riding a regular pedal bike, I would say this is close to but not quite fast enough to feel comfortable among urban traffic. Yet raising the limit to say 20mph could feel arguably unsafely fast on a shared use path through a park. It's a dilemma.