If one factors in the tax on a car purchase, the income tax paid by everyone employed in the car industry and all business's dependant on vehicles, fuel duty and VED, and the fact that only a fraction of the VED alone is spent on roads every year then I'd suggest revenue collected as a consequence of the motor car must subsidise a lot of other things e.g. NHS, Asylum seekers, London etc etc.
I do use my vehicle for dozens of completely unnecessary trips but I've Just been to the Coop in the SUV for some
milk, jelly babies and Soreen - it is about 450 metres though so I could argue it was justified. Also every trip I take I always think the fuel duty I pay is helping to pay for a Romanian Asylum seekers lunch.