The numbers have not been finalized but the Cash for Clunkers program resulted in some 700,000 old gas guzzlers being replaced by newer, more efficient vehicles.

While the program stimulated auto sales to an annualized rate of 14 million vehicles in August, it was also sold as a way to reduce both emissions and gasoline use.

I don't know about emissions, but as far as cutting gasoline use it was a success, albeit very modest based on back-of-the-envelope calculations.

I'm figuring conservatively that the average increase in fuel efficiency was about 5 miles per gallon, from 18 mpg to 23 mpg. Taking the standard number of miles driven per year at 12,000 - which I think is low - that equates to savings of 145 gallons of gas a year for each new vehicle.

Multiplying that by 700,000 new vehicles and we get overall savings of 101.5 million gallons of gas a year.

Better than a spank in the eye but frankly a pittance compared to the 378 million gallons of gas that the United States consumes every day, according to the Department of Energy's Energy Information Administration.

- Peter C.T. Elsworth