GM held a triumphant press conference this morning, announcing that, using newly devised EPA methodology, its 2011 Chevy Volt will get a whopping 230 miles per gallon in city driving, by far the highest fuel efficiency rating ever. No car has ever so much as sniffed 100mpg before; the Prius gets 51. But there’s ample cause for skepticism, Cars.com blogger David Thomas explains.
GM’s using a new EPA system for plug-ins, the details of which aren't yet known. The Volt can run for 40 miles on just electricity, and 300 thereafter, so if it had a 10 gallon tank, it would get 34mpg overall. But the new system assumes hybrids will travel more city miles on electricity alone. If the EPA assumes a low enough cycle between plug-ins—say 40 miles—it would lead to incredibly inflated results.