[OtterCoder]

Can I just mention how mind-bogglingly stupid a milage tax on car registration would be? No matter how efficient your new car is, it's less polluting to repair the old one and keep it on the road, than to manufacture a new car.

[cptskippy]

I think you're missing the point. The tax goes towards infrastructure maintenance. All vehicles damage infrastructure and the amount of damage a single car imposes is a function of their weight and miles driven.

From an environmental view, the tax would be for cleaning storm water run off which contains contamination from the vehicle itself (e.g. oil, brake dust). From that perspective an older car is more likely to polute storm water than a new car.