Ha ha ha...if you look back you'll find that all motor vehicles were driven from the "right" side. This seemed natural,as all horse driven vehicles had their drivers sitting on the right side of the carriage. Even in your part of the world! Now,what happened to change that,I don't know;But,I bet it was political.
Oh,and Alice Springs-Tenant Creek...do you remember the Stuart Hwy. not sealed till the Eighties south of Alice! Bit different to the US I think,on the given pics.