Port Augusta is a town in Australia.
There is a main petrol station / truck stop in the entrance to town. It's a real trucks' hub giving you an excellent chance to catch very long rides. If you need to get long distance rides from anywhere within a 500km radius, trying to hitch to Port Augusta would probably be a good idea.
West towards Ceduna or South towards Port Lincoln
Unfortunately many truck drivers aren't allowed to take passengers, so try this spot instead!
Walk out of town (or get dropped off) where a big information wall is. There is plenty of space for cars to pull over and the road is very long so drivers can see you for a long while. Certainly every car which passes through there is not local traffic and will go further West or South.