Nudgenomics: Why 'cash for clunkers' works

The U.S. government is committing $23.7 trillion to various rescue programs and it has raised the national debt to $11.3 trillion. Are any of these programs doing a shred of good? For the most part, it's hard to tell. Admittedly, unlike last fall, I don't spend every Sunday night writing about the latest multi-billion Wall Street collapse or bailout.

But that doesn't mean any of these programs are anything but a finger in the dike -- that is except for one: the "cash for clunkers" or Car Allowance Rebate System (CARS) program, which gives consumers up to $4,500 if they trade-in a less fuel efficient car for a more fuel-efficient one.