General Motors claims the Chevrolet Volt range-extended electric vehicle will get at least 230 mpg in the city when it hits the road late next year. That's more than four times higher than the Toyota Prius, the current EPA fuel-efficiency champ.
"From the data we've seen, many Chevy Volt drivers may be able to drive in pure electric mode on a daily basis without having to use any gas," Henderson said.
The 2010 Prius gets 51 mpg in the city while the Insight hybrid gets 40. Nissan, which recently unveiled the Leaf electric vehicle it plans to offer in the U.S., Europe and Japan next year, has said that vehicle will get the equivalent of more than 340 mpg.