WASHINGTON – President Bush is showing new interest in automobile gas mileage, spurred on by public outrage over fuel prices. But don’t expect the administration to embrace significant increases in requiring how far cars go on a gallon of fuel.

The president wants Congress to let him rewrite mileage rules for new car fleets. Some critics suggest that request could instead spur automakers to produce more gas guzzlers.

The rules are known as Corporate Average Fuel Economy, or CAFE. Enacted in 1975, they were a response to the shocks of the Arab oil embargo. Automakers today must meet a fleet average of 27.5 miles per gallon for its cars, a standard unchanged in two decades.

Bush told reporters last week he wants Congress to “give me the capacity to raise CAFE standards on automobiles.”

The administration has opposed such increases for cars whenever the issue has come up in Congress. Last summer, the White House objected to a proposal requiring the president to find ways to cut U.S. oil consumption by one million barrels a day, about five percent, saying the plan was a “back door” to higher mileage requirements.

So, has the president changed his mind? Not quite.

Transportation Secretary Norman Y. Mineta told congressional leaders he wants the power to “reform” the mileage rules and that the administration would keep opposing tougher mileage requirements under the current system.

Bush’s chief economic adviser, Al Hubbard, acknowledged that the White House has no idea how much the changes, if allowed, would raise car mileage.

Said the Sierra Club’s Daniel Becker: “Given the administration’s track record, this is more evasion than an epiphany.”

The Transportation Department this year revamped its rules for pickups, sport utility vehicles and minivans, setting a sliding mileage scale that is based on a vehicle’s size. The overall standard was increased slightly; smaller vehicles now must meet higher mileage requirements than do larger ones. The biggest SUVs were exempted until 2011.

“It was accommodating to the industry,” said Gerald Meyers, a former auto executive who is a professor of management at the University of Michigan. He called it “probably the friendliest (proposal) that can be brought forward.”

When it comes to cars, automakers still must meet an overall average; there is no breakdown by size. The administration has indicated it would like to do to cars what it has done with small trucks.

The White House says it needs approval from Congress. Some lawmakers disagree.

“He has that authority already,” said Rep. Edward Markey, D-Mass. He views Bush’s request to Congress as “a backdoor attempt to stall on real increases in fuel economy standards.”

Rep. Sherwood Boehlert, R-N.Y., and Markey, repeatedly tried unsuccessfully over the past five years to get tougher mileage requirements into energy legislation. Boehlert said the administration “is finally getting the message.”

But Boehlert said Mineta’s request “is designed as much to limit progress as to foster it.”

“The secretary’s response is `just let us do it'” and head off any congressional mandates on automakers, Boehlert said.

The White House says the changes for small trucks and SUVs sets the “most ambitious fuel economy goals” in the program’s 27-year history. The administration claims the changes will save 10.7 billion gallons of fuel over the lifetime of new vehicles by boosting the requirement from 21.6 mpg to 24.1 mpg by 2011.

Yet David Friedman, director of the Clean Vehicles Program at the Union of Concerned Scientists, says the new rules will have little effect on gasoline consumption.

“It will save less than two weeks of gasoline a year and loopholes could actually undermine those savings,” Friedman said.

A similar system based on weight or size for cars “will encourage automakers to make bigger cars,” he predicted.

The debate over improving mileage mainly has involved concerns that higher requirements would force automakers to make smaller and lighter cars that opponents of the CAFE system contend are less safe.

Tougher requirements under the current system “would increase fatalities, raise health care costs and reduce employment,” Mineta wrote lawmakers.

Counters Friedman: “Those are the automaker arguments, not the arguments of the scientific community.”

Boehlert, chairman of the House Science Committee, said it bothers him that Mineta “trots out the same old misinformation linking CAFE standards to safety reductions.”

A report by the National Academy of Sciences in 2001 said highway fatalities rose when automakers rushed in the 1970s to meet the new requirements by reducing cars size and weight.

But the study also said future mileage improvements can be met with technology changes – new engines, transmissions and aerodynamics – to avoid such downsizing.