Especially e-bikes are gaining a lot of momentum. They take away the sweat factor of regular bikes while still having massive health and congestion advantages over car commutes (and within the city are often faster than cars due to congested streets).

People hurt themselves on E-Bikes, I can see it being a fad when people realise it's a relatively dangerous way of travelling.

In the EU ebikes are quite limited. If you're going to hurt yourself at 17mph on an ebike a normal bike isn't going to safe either, as soon as you go down a hill. American ebikes seem to be crazy powerful.

People hurt the planet with cars, I can see it being a fad when people realize it's a relatively dangerous way of traveling.

People also hurt other people with cars. What was it again? You are more likely to die from a car accident than in an airliner?

I was in my local bike shop [1] yesterday and probably a quarter of their bikes on display were electric. They are mainstream now.

[1] http://www.bike-zone.co.uk/