The EPA's new gas-mileage labels are good but not perfect

THE ENVIRONMENTAL Protection Agency is asking for comments on its proposed new gas mileage stickers for automobiles -- so here's ours. On the whole, both of the agency's two suggested alternative stickers represent much-needed improvement over current fuel-economy labeling. They more clearly and brightly inform consumers of exactly how much fuel the various models can be expected to consume, how much greenhouse gases they can be expected to emit and how they perform in comparison to similar models. We especially like the part where the EPA estimates how much gas money the labeled car would save the consumer over an average vehicle.

But we have reservations about the version that awards vehicles letter grades ranging from "A" to "D" based on their fuel economy and emissions. This seems to cross an important line between informing the public -- an appropriate role for government -- and salesmanship -- a dubious mission. A related problem is that the EPA's proposed letter grades apply to all vehicles regardless of their fuel source. Thus, they would compare apples (electric vehicles, plug-in electric hybrids) to oranges (gas-powered cars and trucks). Nissan's all-electric Leaf due out later this year, would earn an "A-plus" from the EPA, because it directly emits no carbon dioxide and consumes no gasoline. But the highest grade even the most fuel-efficient gas-powered car could earn is a "B." And the high grades for electrics may be misleading. Their power would ultimately derive from a utility somewhere, which might be low-carbon nuclear or high-carbon coal. In practice, it's very hard to sort out this complexity to everyone's satisfaction.

Better just to supply consumers with raw numbers and let them rank cars according to their own criteria, with no letter grades or other suggestive words, such as "best" and "worst," which the agency also proposes. Meanwhile, if the government really wants to steer people to buy fuel-efficient vehicles, and offer manufacturers incentives to build them, it will have to do more than just tweak the labels. Higher fuel taxes would help. Fuel-efficiency experts at the Massachusetts Institute of Technology have proposed a "feebate" system that would essentially reward consumers with cash for trading "up" to more fuel-efficient cars and penalize them for trading "down."

To the extent the program does not pay for itself, it could be funded by scrapping wasteful current policies, such as ethanol subsidies. When it comes to encouraging conservation, information is good -- and money is even better.