[Brillig]

What you subsidize you will get more of.

We subsidize highway construction and maintenance from corporate and income taxes, less so from gas taxes (and other user fees - tolls etc.).

If roads were supported entirely from gas taxation, the price of gas would be more in line with European prices (double to triple what we pay) and reflect real costs of miles driven - and fuel economy would quickly mirror European numbers. Economics would compel it for the masses. The richer elements would still have the option of dissipating their wealth on conspicuous consumption (Giant daily use cars)

As it is we have a false economy which makes it artificially cheap to drive relatively less efficient cars - the Truck fleet is efficient, ton for ton, in comparison to the Hummer and SUV fleet - seems harsh to pick on the truckers, and subsidize the Hummers.

No way a 'federal mandate' will change laws of thermodynamics - and 8 or 10 mpg for a 40 ton vehicle beats the heck out of 20 mpg for a 2 ton one. Especially if the truck is bringing groceries to market, and the Hummer is the daily commuter, or shopping cart.

Tax subsidies create false economy and encourage waste.

And yes, I am prejudiced against the Hummer, and other tank like SUV's.