Its only a matter of time until goverments have to figure out some way of charging that does not involve a pay at the pump model.
If alternative fuels like CNG or electricity ever take hold you are not going to be able to tax them at the pump, but you still have to pay for roads.
Personally, I would prefer to see some kind of toll based on who actually uses the roads.
CNG could be taxed just like gas at the pump is. All the gas company needs to do is put meters on the furnace and water heater to measure what you use for heat and what your use for automotive fuel.
Same with electricity, cars are equipted with a rfd tag that is read by the plug in, electricty used for the car gets a tax at certain rate, depending upon what they figure average KW needed to drive X number of miles.
Or just have higher vehicle registration rates (and federal registration) for non gas/diesel powered vehicles to make up for the tax not collected at a pump.
