Cars don’t burn fuel. Drivers do.
The main premise of the “Cars for Clunkers Program” is removing fuel inefficient “clunkers” in exchange for new fuel efficient cars. Does that mean drivers who switch to more fuel efficient cars consume less gas? No.
Just like regulation of guns and drugs, making cars fuel efficient doesn’t make their drivers fuel-efficient. I drive a 1993 Nissan Maxima (at 19 mpg combined, doesn’t qualify as a clunker), and unemployment has reduced my carbon footprint significantly. When I finally do work in NYC, I’m probably going to take the bus and subway there. So it doesn’t matter whether my next car is a G8 or a Prius, it is up to me how much gas I would like to consume, not my car.
Of course, Cash-for-Clunkers also help remove usable and cheap cars off the market (because manufacturing new vehicles is so environmentally friendly) , reward the fine and honest folks at the car dealership, create incentives for actions people will do anyway. Otherwise, you’ll feel good.
The only question is then, if new cars are so important, why not have a $4500 tax credit on other consumer goods?