Cycling boom in Berlin. Why?

Everwhere where politicians and planners start to take cycling seriously and listen to the concerns of cyclists relating to safety, and consequently start building separated infrastructure, the numbers of cyclists increase dramatically. What's more, you'll start seeing a different mix of cyclists: more seniors, more kids, more women. This is what's been happening in Berlin, where hundreds of miles of separated bike paths and lanes have been added to the cycling network in recent years, according to this article from BBC News Magazine. People feel perfectly safe on their bikes, and most don't wear helmets.