The upshot is that in NSW you'll see the trucks drop back, time their run and come flying through into the double lanes or they won't make it. I'll disagree about being state specific - NSW is worst by far for this.
Come over the border into QLD and clowns (not van drivers either) just sit in the right hand lane and clog it up - they might even slow down a bit.....
We could learn a lot from NZ. They have awesome traffic signs like "A few vehicles behind you? Pull over and let them pass", simple effective messages that make roads efficient. Of course people would need to pull their heads out of their arses over here to read them.