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Subject:  Re: cahs for clunkers - disaster of a program Date:  1/11/2013  8:53 AM
Author:  markbrynn Number:  47268 of 92777

telegraph wrote:
At 20 mpg for a car and 10,000 miles a year, a driver would use 500 gallons of fuel a year. with a newer car that gets 24 mpg, he'd save all of less than 100 gallons. your payback in energy costs would be over 18 years!


I'm not arguing whether the program was a success or not, I just don't like faulty math, or worst case assumptions that are then used 10 posts later like they are facts.

If you trust that 1850 gallons are used to make an average new car (I have no idea). And use the stated mpg gains in the report (from 15.8 to 25) and not the minimal required gains in the law (4 mpg better than the old car), which is a massive difference by the way. Then you end up with the following (quick google search showed average mileage is anywhere from 10k to 15k per year, and 20k was mentioned in one article):
10,000 miles driven per year --> 8 year break even point
15,000 miles driven per year --> 5.3 year break even point
20,000 miles driven per year --> 4 year break even point

This is a far cry from what telegraph calculated and then used as if it were a fact in later posts. There may be some wrong assumptions in both sets of calculations, I'm just using what was already quoted.

If my version of the calculations are correct, then it at least makes this part of the argument against the program a lot less convincing.

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