Dealers say grades could hurt car sales

The fuel economy stickers, which have been required to be displayed on all new cars since 1977 and were only redesigned once, in 2007, would show a large letter grade from A+ to D based on the car’s carbon dioxide emissions and combined fuel economy. It’s similar to the rating system in the United Kingdom, where cars are taxed on their carbon dioxide emissions.

The rating system is designed to promote electric cars — those vehicles get an A+, while most average cars would get a B. About 1,980 models would rank in the B and C ranges, whereas only 14 current models would receive an A-.

The proposed ratings have rattled some dealers, many of whom are still recovering from one of the worst automotive sales years in nearly two decades.

“Anything that’s not an A is bad, right? It’s misleading to the consumer,’’ said Chris Lee, owner of Lee Volvo in Wellesley, who added that unlike the current city and highway numbers, a letter wouldn’t indicate how a car performs in different situations. “I could be selling a customer a D, but if you’re driving mostly on the highway, it could be an A.’’

Joe Lawlor, a sales manager at Westminster Dodge in Dorchester, agreed. He said he would prefer the government try to stimulate car sales rather than devising new labels. “I think it’s foolish and more government intervention where it doesn’t need to be,’’ he said. “People aren’t idiots.’’

Under the new design, the city and highway ratings would be eclipsed by a large, boldface letter set in a circle, colored to correspond with the grade (bright green for As, a darker orange for Ds). Two new ratings, the grams of carbon dioxide produced per mile and the number of gallons of gasoline consumed over 100 miles, are set below a fuel cost estimation and a barcode to relay the sticker’s info to a cellphone.

Another proposed version of the label drops the grades in favor of highlighting the car’s combined fuel economy rating (both city and highway). For electric cars such as the 2011 Nissan Leaf, the EPA says it may show a mile-per-gallon equivalent, though the testing procedures for all-electric and plug-in gas-electric hybrids have not been decided. The grades may also be curved based on current emission ratings decided by the California Air Resources Board. The agency is soliciting public comments for the next two months before the labels are approved for the 2012 model year.

Some local car owners yesterday afternoon seemed to welcome the idea of the sticker. Raj Dhanda, of Brookline, said the letter grades would “absolutely’’ affect his decision to buy a new car if he had a long commute. He’s awaiting delivery of a rare Mercedes SLS AMG, which has a 563-horsepower engine and a top speed of 197 miles per hour. That puts it close to a D+.

Dan Breslin of Canton, who was waiting in the service department of Expressway Toyota in Dorchester, said he likes the idea of adding more information on the label. “We kind of assume that the mileage and the impact on the environment is the same,’’ he said. “If they’re not, it’d be good to know.’’

Clifford Atiyeh can be reached at catiyeh@globe.com.