Germany and Switzerland are very strikt.
When the limit is 60 km/h, you better drive <= 63 km/h. Deadly accidents happend in this "60 km/h-construction-zones" on German Autobahn.
In Germany, stay right(!), even when you drive 180 km/h. May be a BMW, Benz or Porsche likes to pass you with 230+ km/h.
I had 2 US executives in my car, bringing them from Cebit Hannover Fair to Hamburg Airport. First they were exited at 200+ km/h, later they were falling asleep in the car ... fairs have long days and loooong nights..
Next, keep distance. On German Autobahn you will see boxes on bridges; they make a nice photo of you and your car and the license plate, when you are driving without distance.
Radar detectors are not allowed in Germany.