The milage tax will discourage use of hybrids,  going green, will just be some kind of fashion statement and nobody will want to mess around with the more expensive hybrids.

The left is on both sides of this issue, on one hand they want the enviromental friendly cars, but in reality they want the revenue that the bad gas milage SUVS and pickups, full size vans, muscle cars, ect...bring in.

4 problems. 1) Government is in charge, and the transponder idea is a major infringement of privacy and fifth amendment rights, among other things.  Imagine Big Brother tracking your every movement. 2) Government would have to build a huge bureaucracy to monitor 300,000,000 people, and then collect the taxes.  3) Taxes are almost always fungible - so when you collect a new tax, even if genuinely earmarked, it won't decrease other taxes and won't decrease spending, both of which will gradually creep back up to fill the tax well at a higher new level.  4) Michigan can't even allocate road money correctly based on demand - that is, disproportionate shares of road money are spent on underutilized northern roads because the formula is out of whack.  Whose to say that a federal system - if perfectly collected - is going to evenly fix roads when no state system has figured it out.  At least with state politics, we have a chance - and at least the dollars are going somewhere in the state.

I think the hybrid segment of the market, really demonstrates better than anything, how the market does work to fix its problems,

alot of these technologies are still in the development phase, and not even out on the market yet, the idea of the mileage tax for these cars is like doing an abortion on the new hybrid  segment of the automakers market.

The high performance sector of the automotive market was killed in about 1972 or 73 by Nader.
Do you remember 450 horsepower 455 Olds W30 engines, Plymouth Roadrunners, ect...
Government came in and said we don't want you building that stuff, then the next few years, they were forced to build stuff people did'nt really want.