Tax evasion

In their neverending quest to cheat the states out of their well earned taxes, Americans have found a new way - fuel efficient cars. Since a large part of your fuel prices goes to your state you are robbing your fellow citizens of their needed highway funds by switching from that hummer to a hybrid! But don't worry, the solution is imminent. Tax them by the mile. Really easy math, if you'd driven your hummer at 10 miles to the gallon, and at 50 cents tax on fuel per gallon, that's $5 per 100 miles driven. A bit of big brother (can't have people cheating, we need real time milage collection via GPS), but that cannot be avoided (possibly due to the needs of the war on terror).
See, and you thought, if you'd get everyone to switch to that hybrid with 60 miles to the gallon, you could save that alaska preserve. Silly you.