Thank you for raising awareness about the problems with MPG. I wanted to let you know that we've created a web-based tool to help people convert MPG to "GPM". These calculators let people see the actual gas consumption (and savings) of different cars. One calculator can be used for a choice of MPG, distance, and gas price. Two other calculators allow consumers to examine new 2009 cars and evaluate them based on GPM (using MPG data from the EPA).
These calculations are critical to helping people see their true gas consumption (and carbon emissions) and not be tricked by MPG. I hope they'd be of interest to readers or could be posted with guides to car buying. I'm eager to see either the EPA or Consumer Reports adopt GPM, and am trying to provide the necessary tools in the meantime.
A few other links that might be of interest:
I'm maintaining a webpage here that explains the problems with MPG and argues for GPM.
And "gallons per mile" was featured in the New York Times Magazine's Year in Ideas.
Thanks again for your interest earlier in the year.
Professors at Duke University sent a kind thank you note to the Sierra Club for stories earlier this year in the Compass and Green Life on why gallons per mile is better than miles per gallon. Here's the note: