Mopeds used to be quite popular in Europe and still are among younger people,who need affordable transportation. With increasing prosperity people increasingly favored cars,although with the prevailing crowded road conditions, alternate modes of getting around often make more sense.The wet climate in Europe also was an important factor.In the fifties and sixties power assisted bicycles were quite popular,usually add-on friction drive designs,but the mopeds gradually took over,with increasing prosperity.From the eighties on a large section of the population could start affording cars and the number of two wheelers of all types dwindled,creating all sorts of traffic nightmares.The authorities are now atempting to lure people back on bicycles.In general distances in Europe are far shorter than in the US and the need to go faster (and use power assist) is less acute.So I'm not so sure that Europe is going to lead the way neccessarily.I do think that "greener" electric bikes are going to be popular there.All energy is expensive over there esp. hydrocarbons (10 $ per gallon for gas !)