Beautiful route! It must be so much fun to pedal past all of the folks stuck in their cars! One thing I did notice though is it seems all of the other riders were riding without a helmet or wearing an ordinary hat.
yes, Europe is general is not so helmet-conscious like the US. most of the Mountain Bikers wear helmets and on the trail almost everyone has a helmet, but maybe half of the road racers were helmets (they usually were the cycling caps or a bandana) and almost none of the recreational riders were helmets: riding through the park or to the beer garden to a short distance to work...
and it's not just with cyclibg: i also wear a helmet for snowboarding, downhill skiing and inline skating and in Europe you see very few - from my experience in the US ski areas you now see almost 50% with helmets and Europe is more like 5%...