The extent of biking in the Netherlands is phenomenal, both in the countryside and in the cities. I have visited in the Hague a few times and the vast majority of car drivers simply adapt their driving to all of the bicyclists - at some point they bike, too, so the awareness is astounding. You will see lots of granny-bikes, parents hauling 1, 2 or even three kids (two child seats behind on the back rack and one small toddler seat on the handlebars). Besides driver awareness, however, part of the safety of biking in the Netherlands is that the cyclists are also responsible. Peddling along at a comfortable, non-sweating pace to work also means that the cyclist doesn't make rash manoeuvers in traffic - with only 1 meter between the park cars on the side of the road and cars and streetcars, it requires that cyclists stay with the flow of bike traffic.
In the countryside it is fascinating to watch all of the kids biking into the villages for school - not on the roads, but on an extensive network of bike paths. On the weekends and in the evenings then the cycle clubs head out en masse. Pretty cool to see a bunch of old boys in club colors zipping along.