A few years ago, I drove the west autobahn in Austria. Inconveniently, there are no speed limits posted: The authorities just assume you know it's 130 Km/h unless posted otherwise. So didn't know and had speeds up to 160 or more Km/h (our rental car was substituted last-minute for my wife's cousin's 10 y.o. Audi 4 diesel with no a/c (hot hot April)). Seems the worst part for speed traps was near Linz (emission reasons). As far as we know, the cousin did not get any tickets. It's mostly photo radar there (the Austrians know where they are) with the very occasional manned radar trap.