I really have no idea why some people get hooked on this
idea that a mileage tax, with some sort of costly technological implementation, is a good idea. Just increase the damn gas tax. It's already roughly a mileage tax, with the added benefit that it mildly encourages people to drive more fuel efficient cars, which is a good thing from every perspective other than the quantity of gas tax revenues. But if gas tax revenues aren't high enough, just raise the rate.
