Unless youre on toll roads, Adelaides roads are still good. Driven many a road in the back blocks of the western suburbs of Sydney, and they make our roads look like bloody highways (and THAT is saying something hahaha)
I will agree, that bit of road into Dingy isnt the best, id have a guess its a soil related problem (as theres a band of the Victor road in about the same alignment thats bad, Coach Road is not much better, as are those sections of South, Lonsdale Road and Majors Road back up Sheidow / Ohalloran Hill way (and if i scrape the back of my memory banks from Year 12 Geography from 2000, i think there are a few bands of Reactive Clay throughout the South)