NEW YORK (CNNMoney.com) -- Even if they aren't always terribly
accurate, EPA fuel economy estimates have at least made it easy
to compare the gas mileage of one car to another. But now that
plug-in cars are entering the market, things are about to get
much more complicated. How do you compare the fuel efficiency of
a car that runs on gasoline to one that plugs into an outlet?
Last week, Nissan and General Motors each released preliminary
EPA fuel economy labels for their plug-in models. The labels,
particularly for the Chevrolet Volt, which runs on both plug-in
electricity and gasoline, seem sure to provide at least as much
confusion as assistance to potential car buyers. We'll try to
sort out some of the trickier issues. Q: The EPA's label seems
to say that the Nissan Leaf, which uses no gas, gets 99 miles
per gallon. How is that possible? A: Actually, the Nissan Leaf
gets 99 miles per "gallon equivalent," or MPGe. That means the
amount of electricity the Leaf uses to drive 99 miles is
equivalent to the amou