The Australian Road Rules are model laws that have no legal effect. They form the basis of road rules of each Australian state and territory. For the most part, each state and territory has copied the Rules into their own laws, however, not every provision of the Rules has been copied exactly in each state and territory. Also, there are a number of provisions in the Rules that specifically leave certain matters to state and territory governments to determine.
Read the the Australian Road Rules (model law) on the Australian Parliamentary Counsel's Committee website