The feds launched the "cash for clunkers" program recently that pays you to scrap your old polluting car if you buy a fuel-efficient one. This is a great idea that can be applied elsewhere to clean the environment and stimulate economic growth. But just how far could this idea go?

 Buried in Joseph White's interesting Wall Street Journal piece about the enormous power of incremental improvements in auto fuel economy (versus so-called moonshots) sits an interesting statistic:

"Mr. Fedewa estimates auto makers can deliver 10% or better fuel efficiency improvement for about $500 a vehicle." (That is Eric Fedewa, described as "a vice president with the automotive consulting firm CSM Worldwide.")

$500 for 10 percent improvement!

What if the government just paid the costs upfront as part of the stimulus package?  Could we invest in fuel economy standards as a sort of time-release piggy bank?