Interesting article from MSNBC...
Gasoline's New Math: Miles Per Dollar
It's time to look at fuel consumption, and our national chug-a-lug gasoline habit, in a new way.
By Lawrence Ulrich
Toyota Prius (© Toyota Motor Sales USA) View pictures
One of the most fuel-efficient cars in America, the Toyota Prius will still only go about 15 miles on a dollar's worth of fuel.
For decades, miles per gallon — mpg in its familiar shorthand — has been the only way for consumers to understand how much gasoline is going into their tank, and what it really costs. But mpg isn't cutting it any more.
Like leagues, fathoms and pecks, mpg has become a relic, a unit of measure that has lost its meaning. It's a quaint reminder of the days when a gallon of high-test cost a buck or less, and Jimmy Carter donned his fuzzy cardigan and kindly asked everyone to crank down the thermostat and conserve energy.
It's time for new rules, and new math: Miles Per Dollar, or mpd.
The formula is simple. Take the old mpg, but divide it by the price of fuel. Unlike the vague mpg, mpd is a remorseless measuring stick, its pointy end aimed directly at your wallet. When gas was cheaper than the dirt it sprang from, 20 miles per gallon seemed pretty solid. Even when gas reached a dollar a gallon, you were still getting 20 mpd, traveling 20 miles on a buck.
The problem is that, as a whole, the nation's cars and trucks aren't getting any better fuel economy than they were 20 years ago. With the price of a gallon of gas soaring to $3 and beyond, think again about that 20 mile-per-gallon car. Its mpd rating has fallen to less than seven.....