Though this was the second movie in the Mad Max series, The Road Warrior's post-apocalyptic setting is the one you probably think about when you consider the films. Road Warrior introduced the dystopic battle for oil, warring tribes, and mohawked-players, with Mel Gibson's renegade doing battle with them (his trusty dingo in tow) on the desert flats of Australia. (Believe it or not, the first film took place in the present day, with no WWIII in sight.) The Road Warrior is lots more fun than the original, in my opinion, delightful in its inconsistencies (if they don't have any gas, why does everyone waste so much of it by riding around in circles all the time) and in its over-the-top acting, set design, and kooky plot.
Aka Mad Max 2: The Road Warrior.