https://www.swan.wa.gov.au/News-Media/2016/Focus-stories/Gran-Fondo-road-closures-announced-for-September-4
September 4 is the Gran Fondo cycle race and it takes in roads for the quarries and climbing in and around the Darlington/Hardey Rd area. The link above takes you to the website with all the info, including a map with times of closures and traffic management. Might want to check it out and save yourself some Sunday morning aggro.