Oregon did that a couple years ago. And the cries of outrage were enormous!Wouldn't it be nice if the tax were based on annual mileage and vehicle weight? The tax would be paid without worry about the mode of propulsion.
The state determined that cars were becoming too efficient. Or in the case of EV's, not paying their due road taxes. These taxes were paid when you bought fuel. Gas guzzler = lot's of funds for the roads. Efficient vehicles = lower contribution to the road fund. EV's = no paid road taxes, yet enjoying the fruit of those that paid for fuel.
So, Oregon went to an odometer model. Miles driven = taxes paid. Of course that pissed off those that paid a premium to have hybrids or EV's or newer efficient vehicles. If they are going to be taxed the same rate as a 1970's Cadillac that got 12mpg's, then why bother having a fuel efficient vehicle?
I got my surprise when I first registered my Volt here in Wisconsin. There is a $75 additional yearly fee for hybrids, and a $100 additional fee for EV's. So, I'm paying more to the state because I get better mileage, and they're not getting their dues in fuel taxes.
You can't win for helping yourself and the environment......