Washington ? The Bush administration announced new fuel economy standards Wednesday that, in a break with past practice, would cover the largest sport utility vehicles for the first time.

The new fuel standards would be phased in slowly through the 2011 model year. They would save 10.7 billion gallons of gasoline over the lifetime of the vehicles, Transportation Secretary Norm Mineta said in announcing the final rule in Baltimore.

“We took a good, close look at automakers’ plans, examined new technology that is in use or under development – like hybrids and the latest generation of diesel-burning engines – and decided that we could ask more of the manufacturers than we proposed last August,” Mineta said.

Under the reformed corporate average fuel economy, or CAFE, standards, vehicles sold in 2011 will average about 24 miles per gallon, up from the 22.2 mpg established for next year’s new models.

Higher fuel economy standards “will be a challenge, even with all the new fuel-efficient technologies on sale today,” said the Alliance of Automobile Manufacturers, an industry group for the automakers.

The top makers of light trucks in 2005 were General Motors Corp. with 26 percent of the market, followed by: DaimlerChrysler AG, 23 percent; Ford Motor Co., 19 percent; Toyota Motor Corp., 12 percent: Honda Motor Co. Ltd., 7 percent; Nissan Motors, 6 percent; and Hyundai Motor Co. Ltd., 4 percent.

Environmental groups were disappointed in the final rule.

“By failing to require Detroit to make significantly cleaner, more efficient vehicles to compete with Toyota, the Bush administration is giving the Big Three enough rope to hang themselves,” said Daniel Becker, director of the Sierra Club’s global-warming program.

“Fighting America’s oil addiction with these standards is like fighting lung cancer by smoking 49 cigarettes a day instead of 50,” said Don MacKenzie, a vehicles engineer with the Union of Concerned Scientists.

The final rule is a modification of a plan initially proposed by the National Highway Traffic Safety Administration in August.

The major difference in the final rule is that large SUVs – such as the Hummer, produced as a joint venture between GM and AM General – will be covered. The final rule also eliminates a proposal to create six categories of light trucks based on size that critics said would have led to automakers gaming the system.

Instead, the rule offers continuous fuel-economy standards based on the vehicle’s footprint.

The new CAFE standard leaves the marketplace free to decide what kinds of vehicles should be produced, rather than dictating a mix of vehicles to automakers, the government said in its final rule.

The government said the new rule also minimizes the adverse safety impact that resulted from loopholes in current rules, such as giving automakers incentives to design passenger cars to be classified as light trucks, which can increase rollover risks.

The final rule doesn’t increase the fuel economy standard beyond what was proposed in August, even though higher projected fuel costs would make tougher standards economical.

The Transportation Department estimated that the cost of complying with the rule would be $6.7 billion and the benefits would be $8.1 billion.

For the 2011 model year, it would take 4.4 years of typical driving for the increased purchase costs to be paid back by increased fuel economy, the government said, based on an average fuel cost of about $2.39 a gallon.

The impact on employment in the automotive industry is expected to be minimal, the government said, concluding that the new standards would cut sales of light trucks by about 11,000 units.