Just to clarify, by Aus are you referring to Austria and not Australia? In Australia the road culture is so bad that they make dramatic TV shows about it and relative Youtube channels sharing dash cam footage of bad drivers are actually source of entertainment to many.

But Aussies don't speed as much as those in the US from my experience!

That’s only because we regularly get very steep fines and penalties for exceeding the limit. Even by as little as one kph.

Or their idea thereof... when I use my GPS it surprises me how low my car actually reports my speed compared to reality. It probably explains all the slow drivers in the right lane over here.

Go on the M4 though and 10 over is too slow for many!

How are you checking the real speed? Most GPS receivers display more accurate speeds than car speedometers do.

I'm assuming the GPS is accurate. I've driven through speed traps with it just on or over the limit and been fine. My car on the other hand is reporting around 5 kmh higher, depending what angle I'm holding my head at.