Dead right, I've just thought about it for a second: cruiser at max load 3300kg, GS fully loaded 1550kg, hmmm the math is pretty straight forward. And its NEVER occurred to me to check interstate laws. I have to agree with KB's train of thought: there should be just one set of road rules/laws for Australia. It's not like we get stopped at a state border or anything. I really feel for transport drivers going interstate all the time. I think MarkGU does a bit of this sort of thing.
Funny you say that NBD....
Being a trucky and on the management team for transport law in our business can tell you that the powers that be are slowly aligning laws between states, you'll notice the law in Queensland has introduced 4x4 regulations more inline with NSW (tire size, lift height etc) Trucks will also follow one set of rules Nationwide eventually but like any qov dep this stuff take years if not decades to finalize, they are the red tape kings after all.
Unfortunately Queensland is the state still in the dark ages when it comes down to it, this state is the one that needs to catch up, however don't tell them that, they think the rest of the world follows their transport model - self proclaimed "Smart State" funniest thing since NSW said they would win origin this year.
As for speed limits, you can actually get fined for going too slow - it's more about driving etiquette than a set minimum speed, like whats being discussed in this thread previously, as long as you yield to traffic you can comfortably sit on 80 in a 100 zone, if however you constantly drive below this (example only) say 60-70 in a 100 zone expect to get a ticket.
Like running an amber light it's at the enforcement officers discretion if you are issued a fine or a warning
Bare in mind driving 30% below the speed limit is considered dangerous driving and accidents DO happen because of it, I've seen it all too many times.
My2c
