Yet countries with much higher speed limits and greater population density than ours have lower fatality rates.

And yes, the 80km thing is crazy. Not just on freeways (because at least with 3 lanes they have the option of the far left which is where people who drive under the limit slow should be) but on country highways too. One L plater or P plater can cause a back-up of traffic for miles which in turn makes people attempt stupid overtaking maneuvers.
Perhaps other countries have better driving education?