As I'm living and cyling here [0] most of the year, my impression is: It's a mix of things.

  * In Germany cyclists are not treated well on streets [1]

  * The nature is much more beautiful in NL/Belgium/Luxemburg [2]

  * It is population density and "hilliness", too. I.e. there are
    more people using a bike, when it's flatter, imho.

  * The infrastructure and law in Netherlands and Belgium are much
    much more cycling friendly.

  * The culture in Netherlands and Belgium is much more outdoor
    sports friendly, thus the average person and car driver
    treats you better. Guess where all the "classics" of road
    cycling are?

[0]: http://labs.strava.com/heatmap/#8/6.26125/52.11946/gray/both

[1]: Mainly due to the focus of the media (ARD, ZDF) on the doping problem, using road cycling as a scapegoat and the sacred car culture in Germany. Each time, I'm training on German roads, my life gets threatened at least once since 2006. Thus I train in Netherlands and Belgium for 99,9% of my time.

[2]: Especially in the link provided by mxfh in https://news.ycombinator.com/item?id=7688974

You mean competitive sports cycling. Everyday commute or leisure cycling is awesome in Germany. (Well, I often get aggressively almost run over by ruthless sports cyclists who treat every way as their highspeed training center every now and then...)

Good point. I know many fellows, who forget that they are moving way faster than expected and it's the competitive cyclist to blame. Oddly enough, I know a few groups who basically race in the traffic; However, the ones I know, reside in Netherlands. Most of the time, when I see conflicts between cyclists and cyclists or pedestrians it is due to bad design (of the pathways of each of one). In Germany often simply a few red stones in the sideway are defined as cycling path. Recently, cyclist traffic gets detached from the sideway and placed on the road. What is good and basically copied over from Netherlands and Belgium. A downer at this point is, that the state doesn't change the width of already existing roads, though it would be possible sometimes. Thus cars constantly are driving on this "cycling lane" or simply forget it is there.

Basically, I'm speaking of (road)cycling and cyclo-cross. Not necessarily competitive. Considering commuting it gets better, as nature and sustainability is more in political focus these days. However, it is _really_ far away from the infrastructure you see in Netherlands and Belgium.

But it is also depending upon what you compare here. So, considering a global view, I guess that Germany is way over the top. Considering good design, Netherlands and Belgium have my wholehearted appreciation. Netherlands even much more than Belgium.

On a side-note: I do not believe Strava neither has much commuter nor too much "leisure" data, imho, most of them are somewhat ambitious.

I was puzzled by that abrupt change at the border as well. It could be market penetration. Maybe bike infrastructure like the bike knooppuntnetwerk plays a role as well. http://www.nederlandfietsland.nl/knooppuntroutes/overzicht-k... Although dedicated bike lanes fall of much more gradually at the border f.i. https://www.google.de/maps/@51.6623341,6.998291,9z/data=!5m1... As a Dutchman I never realised how unique this dense network of dedicated bike lanes and route signs is. Until I met some Canadian bike head expats who couldn't stop raving about it. It seems that if you're into touring on bike and getting around by bike the Low Countries are without equal.