Western Australia is the singular state in Australia I've not driven in, but even then, the driving standards have to be better than the "found in a Weetbix box at age 16" licensing they have here in Texas. The two worst examples I've seen are:
Some guy driving on a freeway, doing 35mph in a 70mph zone, weaving all over the road. The drivers here are impatient at a level that Aussies have zero understanding of. The traffic only has to look like it's slowing down before they all start changing lanes, driving across nature separators between the freeways and parallel service roads all to escape what turns out to be a ten second slowdown.
Anyway, so cars are weaving dangerously everywhere like a swarm of angry bees around this car. Eventually I get up beside him, and he's holding a phone to his head on a phone-call. Yeah, yeah you think. That's not that unusual. Thing is, he's also holding another phone in his other hand watching a movie on his phone, basically steering with his knees, and not even looking at the road.
The other incident was peak rush hour. Cars are on their horns, which is actually a rare thing in Texas, because everyone assumes that everyone else has a gun and will shoot them if you annoy them enough. The problem? This lady was reversing down some 300 meters distance from a freeway merge overpass into the traffic taking the overpass, on a road way that's barely wide enough to fit 2 cars side-by-side. She'd taken the wrong turn off, and rather than doing what most would do, go down to the next side-road bridge over the freeway to turn around to the correct direction, this lady had decided that reversing into 70mph traffic on a narrow bridge 50' above the freeway during rush hour was the better option.
Then there's the moving express lane barricade that gets moved over one lane every single day to make the rush-hour extra lanes. You can drive along that barrier in the morning and see when some 20-40 cars have impacted the barrier and knocked the concrete blocks out of alignment over a 10 mile distance, each and every single day.
So unless Western Australia drivers are doing worse than that, trust me, Texas has you guys beat for bad drivers.