Many moons ago NZ changed from Imperial to Metric speed limits and we had signs with both speeds written on them (30/50, 70/100,)for a while during the changeover and conversion stickers to put on your speedo. The switch all went really well because it was the seventies and everybody was driving low powered Austins and Datsuns.

The "Flush Median" or Middle lane. What happens when two cars travelling in opposite directions want to use it ? We're seeing these more and more in NZ. They just seem like a bad idea to me.

As for the give way rule at intersections, Australia got it right, and NZ got it wrong, and the NZ government will probably change it. I'm not looking forward to that, I think the Automobile repair industry WILL however.

Yes unfortunately in NZ we are having the odd incident of campervan head-ons. The only way to fix this is to abolish visitors driving licenses and have hired drivers ( like Asia ). I don't know how Avia and Hertz will feel about that though.