According to the MPG Illusion blog, the Cash for Clunkers Bill, as it is right now, does not go far enough to improve things. I noted the same thing, but my thoughts were rather vague on the subject. The Duke University researchers at MPG Illusion go much farther on illustrating and proving the point.
GPM - The MPG Illusion: Cash for Clunkers and the 1 GPM Principle
We argue for a 1 GPM principle: A new car needs to save 1 gallon of gas every 100 miles compared to the original car to be carbon neutral. The new car will then offset the CO2 emissions from its own production in 70,000 miles of driving, which would occur in 4 to 7 years for most drivers.
Hopefully, the bill will be either edited or the Senate will prevail using their version before it is passed.
Go read the whole article. Found via Green Car Reports