I've never been to Germany but apparently bicycles and bicycling are taken a little more seriously there than in the US. So much more in fact that the rules for vehicles on the road include bicycles. I personally don't see the point of a flashing headlight, ever, and headlights designed for the German rules don't flash. Some of the new German lights do have daytime running lights though- several LEDs which aren't meant to illuminate the road but which are bright enough for oncoming traffic to see. These running lights are off or less intense at night when the main beam is on....and they don't flash. The beams are also focused so they light the road instead of the trees! I would take that to mean the studies they have done don't indicate that a bright flashing headlight is more safe for any traffic participant. I almost always want to say something to somebody with an annoyingly bright, blinding headlight, whether it is flashing or not...and I ride a bike more than I drive a car. I try to behave as a traffic participant as much as possible and the aggressive gesture of a blinding, flashing light does not make me feel more comfortable. I'm not encouraged that the confrontational sentiments expressed in some of the comments will further the bicycle commuting cause. It's not us vs. them. Sometimes I drive a car and sometimes I'm on the bike.
Peter White is the guru of all things related to proper bicycle lighting IMO.