Edmunds: "Start Over" on MPG Rating System

SANTA MONICA, California — The age of the alternative-energy vehicle has dawned, and Edmunds.com says fuel economy ratings deserve a fresh look. The consumer Web site, in an open letter to the U.S. Environmental Protection Agency and Department of Energy, says it's time to tear the outdated EPA mileage stickers off new vehicles and overhaul the way consumers are told about fuel economy.

Edmunds CEO Jeremy Anwyl says the effort to convert various types of energy — hybrids, electric vehicles, and traditional internal combustion — to a single MPG standard is "missing the point" and can even be misleading. If the reason for those window stickers is to let consumers get "a sense of the relative cost of operating a vehicle on a day-to-day basis," he writes, it would be better to give a cost to operate the vehicle during a typical month.

That's because a simple mpg or equivalent can look better on paper than it turns out to be on the road. The advantage of EVs over traditionally fueled vehicles, Edmunds says, is "nowhere near as great as the proposed EPA ratings would imply." For example, the 2009 Mini E, an all-electric vehicle, is rated by the EPA at 99 mpge (equivalent), and Edmunds estimates it costs $49.39 per month to operate. The Chevrolet Volt plug-in hybrid is rated at a much higher 230 mpg, but Edmunds estimates it will cost $53.55 per month to operate.

Edmunds suggests that the EPA define a real-world "driving circuit" that covers a typical month, including commuting, errands, outings and the like. Charging and "other energy-specific assumptions" will need to be factored in, as will costs of various sources of energy. In the letter, Edmunds also urges the EPA to create ways to measure other "energy/environmental usage data points" for carbon usage, recyclability, and use of renewable energy as new technologies continue to proliferate.

Inside Line says: An important idea, and if adopted, one that would help consumers compare apples to apples when deciding what kind of vehicle will work best for their needs. — Laura Sky Brown, Correspondent