Residents of California and Oregon may want to begin donning their tin-foil hats as the states consider ways to boost their revenue. As hybrid vehicles become more popular, these west coast states (and I suppose every other state) will lose a percentage of the income they are currently getting from gasoline taxes; as vehicles become more fuel efficient, drivers spend less on gasoline, which in turn yields less profit for the state. The proposed solution: taxing residents based on how much they drive. But the real kicker is how they plan on tracking mileage; equipping all new vehicles in the state with GPS devices to track just how far they drive, then tax them accordingly. Of course this raises privacy concerns, as the vehicles can suddenly be used for motorist surveillance. The proposal could also cut into sales of fuel efficient and hybrid vehicles, as it a Toyota Prius driver would be taxed the same as a Hummer owner for driving the same distance.