Gas tax becomes Mile tax?

The CA government wants to tax driver according to how many miles they drove each year, instead of the amount of gas they use. Their "logic" is, as car get more efficient, they get more miles per gallon, and hence less tax for the government to fix the road. So they wanted to equip each car with a GPS to track the miles.

Hmmm, in order words, if we drove the same number of miles per year, a big heavy gas-guzzler SUV will pay the same amount of tax as a smaller and way more efficieny Prius, while causing 3 times more damages to the road, emitting 10 times more pollutents and wasting 3 times more of natural resources? (Oh, I forgot, Mr. Bush just took over Iraq. Sorry, I forgot we have cheap oil. Wait a minute..., I am still paying US$2 per gallon!)

After all those years trying to clean up CA air by encouraging people to use less gas (hence less pollutents), now they tell us it is ok to drive big heavy SUVs which cause more damage to the road and air? Only Arnie, with his HUMMER could come up with such a brilliant idea.