To help understand GPM, Larrick has put up the MPG Illusion Calculator on his MPG Illusion website. The Calculator uses the mileage data from the EPA we're all familar with, but presents it in such a way that you get to see how many gallons it takes to drive a set distance. So, for example, I punched in a comparison of the Prius (46 mpg) and the Civic hybrid (42 mpg). If you drove each vehicle 1,000 miles, how much more gas would you use in the Civic? Go ahead and guess. The Calculator says it's just two gallons. You can also use the flash-based tool to compare all 2009 models sold in the US.
Larrich wrote to AutoblogGreen that, "These calculations are critical to helping people see their true gas consumption (and carbon emissions) and not be tricked by MPG. I'm eager to see either the EPA or Consumer Reports adopt GPM, and am trying to provide the necessary tools in the meantime." What's your GPM?
[Source: MPG Illusion]