actually the NATIONAL speed limit is 110kph for all states - canberra is a tiny state populated by politicians - their standard is 100kph "just because".
if you drive from Perth up to Geraldton / Canarvon, it's hard to drop below 130kph. If you head out to Kalbarri or York, there are speed de-restriction zones (ie no speed limit) so you can barrel along as fast as you want.
between horrocks and kalbarri i was sitting on 180kph in my subaru forester - and it still felt like 70!
our problem is australia is that any dolt with a "license" (read can steer and brake without hitting power poles and bus stops) can jump into a hi-po car.
they do this, then end up killing themselves, everyone in the car, and some bystanders.
unfortunately, our "hoon legislation" allows our government to confiscate your car at an officer's discretion - or your neighbour's if they "dob you in". fascism or what, eh?
the general populace don't lay heli's or drift, so everything is targeted around speeding.