It seems somewhat counter-intuitive to give tax breaks on the one hand to a technology, then turn around and apply extra taxes to it for the same reason (using less fuel). It's somewhat like subsidizing tobacco farms, then turning around and paying for anti-tobacco campaigns...

I say they should make the fuel tax then a percentage of the price, or perhaps, a flat portion + a smaller percentage of the price. If hybrid use becomes widespread enough to actually lead to lost revenue for fuel tax, then they should [referring to California] actually use all the fuel tax revenue for the roads instead of consuming most of that money for general government programs.

Diesel fuel already taxed much more heavily than gasoline.

The only other thing I've thought about for a hybrid tax is, how they could they differentiate between hybrid drivers who commute 100 miles a day and drive a lot, as opposed to ones who only make short trips? A flat tax would be horribly unfair, especially considering the whole point is to supposedly make the tax base more fairly represent who uses the roads the most. If hybrid drivers are supposed to pay 25% more tax on every gallon of gas... how would that be enforced? Gas stations would have to keep track of who the hybrid drivers are, and charge them (and nobody else unecessarily, of course) more? That woudl be especially hard if I pulled the "hybrid" badge off of my Civic...

Actually, the idea for California is that, instead of a fuel tax, there would be a "miles driven" tax, where CA cars would be required to have a state-owned GPS tracker and transponder on each car, which would charge per mile driven, multiplied by a vehicle weight factor. Extra taxes woudl be imposed during rush-hour. That idea is worse than even a direct hybrid tax, the state has no business tracking exactly when and where I do all my driving, regardless of what kind of car I drive.