@ai6yr I just got back from a trip to Australia and I was shocked at how much the speed limits are followed, including in moderately heavy traffic where people keep adequate following distance and no one is weaving in and out of traffic. It probably helps a lot that they have a lot of speed cameras (which almost always have signs for them), the files for speeding are steep, like $1000AUD and lose your license after 3 tickets, there is no or very little margin for going over the limit, and these policies are all well publicized - we saw signs like "106kph? OVER IS OVER" in a 100 zone.
Also most newer cars detect the speed limit signs and show the limit on the dashboard and automatically adjust the cruise control to match. Which is annoying when the exit ramp has a 50 limit and it detects that instead of the 80 on the highway.