Despite growing awareness of its various problems, private automobile use is still seen as an inviolable individual freedom. We consider the ethical arguments for and against private automobile use with particular reference to John Stuart Mill's theory of freedom. There is much evidence to show that private automobile use is an other-regarding harmful activity that is, therefore, on Mill's terms, liable to public control. Although it cannot be an entirely self-regarding activity, we consider private automobile use in this category and argue that even on Mill's terms it can properly be subjected to extensive control. We also challenge Mill's theory and argue that private automobile use lacks adequate moral justification. We then consider the policy implications of this ethical argument and review some of the policy options available. We conclude that although an immediate total ban on private automobile use is justifiable, it is inadvisable at this time and that more limited, but effective control should be implemented in preparation for a total ban.