THEGREENGROK    Statistically Speaking

Statistically Speaking: Cash for Clunkers Wrap-Up

by Bill Chameides | August 21st, 2009
posted by Wendy Graber (Researcher)

Permalink | 10 comments


Is it better to junk or to pump?

Update – 9/11/2009: The federal government’s Cash for Clunkers program (officially called the Car Allowance Rebate System) traded a total of 690,114, just short of our estimate of 720,000.

The final mileage difference between the scrapped clunkers and the new cars was was 9.1 miles per gallon (0.5 mpg down from the initial estimate of 9.6 mpg) and the final price tag was $2.877 billion (about $123 million off the $3 billion estimate).

Adjusting for these differences, the actual gasoline and carbon savings were a bit smaller than our estimates below. However, due to rounding, only one stat changed: instead of our estimated 1.6 million metric tons saved, CO2 emissions savings were actually 1.5 million metric tons.

With the Cash for Clunkers program scheduled to end on Monday, here’s a sneak peek of its net impact on the nation’s fuel consumption and carbon dioxide emissions.

A couple of the key climate objectives of this program were to

  • Reduce our dependence on foreign oil, and
  • Lower U.S. emissions of pollutants, including carbon dioxide (CO2)

by getting gas guzzlers off the road and replacing them with more fuel efficient cars.  So how did the program fare? Was it worth it? Here are some preliminary numbers.

Cash for Clunkers: How Many Gallons of Gasoline? How Many Tons of CO2

Estimated number of gallons of gasoline saved as a result of the program:  0.2 billion gallons/year*

Estimated drop in U.S. CO2 emissions as a result of the program: 1.6 million metric tons CO2/year**

Direct cost to federal government of the Cash for Clunkers program:  $3 billion

Better Than Program to Get Tires Properly Inflated?

Estimated number of gallons of gasoline saved if all cars in US had their tires properly inflated [pdf]: 1.2 billion gallons/year

Estimated reduction in U.S. CO2 emissions if all cars in US had their tires properly inflated: 10.9 million metric tons CO2/year

Direct cost to federal government to properly inflate car tires: $0

* Assumes a projection of 720,000 cars sold based on CARS data released on August 20, 2009. Also uses the average fuel economy differential announced on August 3, 2009, (clunker with 15.8 mpg to new car with 25.4 mpg) and 13,000 miles driven annually.
** Total CO2 saved from using less gasoline accounting for CO2 embedded in new car.


This post has been revised to reflect the following correction:
Correction: September 11, 2009
As originally published, we mistakenly listed the estimated drop in U.S. CO2 emissions as a result of the program at 1 million metric tons CO2/year. This should have been 1.6 million metric tons CO2/year.

filed under: carbon dioxide emissions, faculty, Statistically Speaking, transportation
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  1. Robert
    Oct 13, 2009

    The CFC Program was a short-term economic stimulus program intended to kick-start consumer car sales. Qualifying criteria included the age of the vehicle, length of ownership and fuel economy.

  2. Drew Rak
    Aug 31, 2009

    Bill: The climate objectives that you cite in the introduction to your blog entry are not discussed in the White House link that you provided. Indeed, the term “climate” is not used in the President’s remarks at all; neither is the term “objective.” I think that you are trying to make the CfC program into something that it was not, so that you can make your point.

    • Bill Chameides
      Sep 2, 2009

      Drew – The White House clearly states one of the objectives is to “reduce dangerous carbon pollution.” Sounds like climate to me.

      • Drew Rak
        Sep 2, 2009

        Bill: While I agree that on the surface it may seem like the link is made in his remarks, do not read into what is not there. The administration (i.e., EPA) has not made a final endangerment determination under the CAA. Thus, they have not made a formal regulatory link between carbon and climate. The adminstration will not make that connection in White House remarks either –least he be viwed as pre-empting the EPA’s regulatory process. They have elcted to wait and see what the congress will elect to do.

        • Bill Chameides
          Sep 8, 2009

          Come on, Drew. You can split as many hairs as you want, but any program with the stated objective to lower carbon emissions is clearly intended to address climate change.

  3. Daniel
    Aug 27, 2009

    I agree with you overall point, but a .2 billion gallons a year savings seems really optimistic to me. I suspect the program will result in a net increase in fuel consumption. The older cars, while drivable, were closer to being taken out of circulation than their replacements. This means more total cars on the road for the next few years. And more cars means more infrastructure, which means more cars yet again. Better fuel efficiency can be offset by increased driving anyway, a difference that may be especially pronounced if gas prices go up again. So I think that’s a moot point. Most importantly, car subsidies keep people away from transit, walking, and biking – the direction we really ought to be going in.

    • paulm
      Aug 31, 2009

      I tend to agree with you here. Wouldn’t it be funny if most those new cars had to be recalled:)

  4. Michael
    Aug 25, 2009

    New cars often have a warning light that tell you if your tires are underinflated. Unfortunately, my new car (which I got through cash for clunkers) doesn’t have that feature.

  5. brian hare
    Aug 23, 2009

    It is not zero dollars to get folks to inflate their tires….you would have to impose regulations / incentives etc to actually change peoples behavior – that would cost money. The real comparison: the chance that .2 billion tons of C02 reduced by Cash for Clunkers = 100% chance inflating tire program will reduce C02 more = 0% Go Obama!

    • Bill Chameides
      Aug 24, 2009

      Brian: Pretty sad commentary. Are your tires properly inflated?

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