One of the most persistent questions around the Chevrolet Volt - aside from whether or not GM will be around long enough to build it - is the fuel economy rating. The problem arises from the unique combination of plug-in electric drive and internal combustion range extender. The current standard test cycles used by the EPA for purposes of calculating the mileage of internal combustion cars are only 11 miles long for the urban cycle and 10.3 miles for the highway. Both of those distances are well within the 40 mile battery range of the Volt. If the current test procedure was used the car would use no gas and this is clearly not a realistic evaluation.

According to the New York Times, the current plan is to run car through each of the test cycles until the battery reaches the "depletion" point. From this data an equivalent mpg figure will be determined. The Volt will then be run on each cycle in charge sustaining mode to calculate fuel consumption. Researchers from the Argonne National Lab are currently studying real world driving habits to determine a "utility factor" for blending the two figures. It is expected that this procedure will yield a final sticker value that tops 100 mpg. Of course, because all of these choices are somewhat arbitrary, the bickering will surely continue for the foreseeable future.