We recently took a look at the new electric cars that are charging into the automotive market, despite the obstacles they still face in displacing the gasoline-powered vehicles that are still king of the road. One reader raised a simple, but excellent question, because it really is at the heart of why EVs are expected to be so slow to swipe market share from conventional oil-dependent cars.

“Electric cars don’t run on air,” the reader noted. “How much does it cost to travel a mile highway and city? I’ve never seen a figure to allow comparison with gas.”

Actually, the U.S. government has long had a great web site, http://www.fueleconomy.gov, that allows U.S. consumers to make just that sort