Back in September 2008 I suggested how gas mileage should be calculated for range-extended electric vehicles like the upcoming Chevrolet Volt: one set of numbers for electric use, and a second set for after the batteries have discharged. General Motors, of course, saw things differently. It wanted the highest possible numbers, both for CAFE and for advertising purposes. And it appears that GM has gotten its way, as the EPA city rating for the Volt will be 230 MPG.

How is this possible? Through a test that makes almost no use of the gasoline engine. Problem is, this figure doesn’t remotely represent the full cost of operating the vehicle.

In a way, though, such a high number will be less misleading. General Motors has so overshot the mark in lobbying for the highest possible number that even the most clueless person will know it’s BS. If they’d finagled a number in the 80 to 100 range then perhaps the average person might have been misled into thinking it was real. But not now.