The problem with cash for clunkers programs is that they ignore the environmental impact of making the vehicles. Compare changing cars every 3 years, each time getting a progressively more fuel efficient car, with keeping the same inefficient clunker for 12 years. The carbon footprint of extracting the materials that went into making the car, especially a hybrid, cancels out any gains you might have made from fuel economy. Then, too, are we recycling the clunkers, or are we dumping them?