"Governments, (...to get us off our addiction to oil) starting at a state level, should use 'feebates' - that is a combination of a fee and a rebate - to broaden the price spread of models with different efficiencies at a given size. So you go to the dealer to buy a vehicle of the size you want and there are more or less efficient models of that size, and [for] the less efficient ones [you] pay a fee. The more efficient ones [offer] a rebate paid for by the fees on the inefficient ones. Fuel taxes are a much weaker way to affect how efficient a car you buy because they are diluted, roughly seven-to-one, by the other costs of owning and running the car, and then they are heavily discounted. So, for a typical buyer, looking at a year or two of fuel savings is about as unimportant as whether to buy floor mats. Fuel taxes encourage you to drive less, but they're a very weak signal to buy an efficient car in the first place."

- Rocky Mountain Institute founder Amory Lovings, interviewed in Newsweek, Aug 6, 07

So, uh, sportbikes would get efficiency-rebates from the taxes on touring bikes (etc...) ? - Mr. Subjective