Tax by the mile?

[Perry Winkle]

The point you all seem to be missing is that this policy would go a step further than encouraging fuel efficiency by discouraging driving in the first place. That would hopefully increase demand for public transportation enough to pull the majority of the USA out of the Stone Age in that regard.

That said, there will always be a spectrum of price sensitivity: some will drive a ton of miles in an inefficient car; some will drive as little as possible in an efficient car. Nothing you can do will change this until congestion and efficiency are non-issues.