Discover Australia reccommends at least 1 kilometer of clear road to pass one of these. I have passed a few and I would consider that to be a minimum guideline. Fortunately, in the outback where most of these work the road is often visible for great distances.
Common sense..These trucks are not even twice the length of the b doubles in Adelaide we now have road trains with 2 full size trailers coming to within 15km of the city They transfer their 3rd trailer to another truck a little further out.Just as a side note if you come across one of these on a dirt road you may find he moves to the wrong side of the road this is so you can overtake without having your vision blocked by his dust.
Clear roadway ahead for a considerable distance, confidence in manoeuvre & & one hell of a powerful car!
Usually, this guys' are in the 'outback', & flick on their right blinker when it's safe for you to pass them, as they are not only higher-up than you, but also can see a few miles ahead. When you go to pass, they move over ONLY enough to let you safely pass. Once you do, beep your car horn, in thanks!
As I haven't driven for many, many years, I have no idea what it would take to pass 1 of these road trains, but I did get a lift in 1, with my young daughter, a friend & her young son, from Oodnadatta to Adelaide, S.A. & that was fun, back in Sept 1999 or 2000
I wouldn't think of passing a road train, they are long, big heavy vehicles, and you don't know what state of mind the driver is in, they tend to do long hours, on our way to the northern territory there were plenty of them, we just used to take our time.