Fuel Inefficiency.

No one's losing sleep in Detroit about the Bush administration's decision to cut $39 million from a taxpayer-subsidized auto industry project designed to create an 80-miles-per-gallon "supercar."

Sure, a car with four times the average fuel efficiency of today's sport-utility would be a sensation, living up to its supercar label at a time when gasoline prices accelerate beyond $2 per gallon.

But the amount being cut represents a small fraction of the $794 million devoted to supercar research in the government's current fiscal budget.

And it probably wouldn't matter if the subsidy were canceled entirely. There isn't a chance, nor was there ever, that a research laboratory would suddenly invent a super high-mileage vehicle, no matter how much money any government -- or automaker, for that matter -- allots to the fantasy.

Automotive technology, like other technologies, evolves one breakthrough at a time, one fragment of knowledge paving the way for the next. It took time to progress from the invention of the heart-lung machine to heart-bypass surgery.

It also takes time and lots of incremental innovation -- such as the development of strong, light metals and plastics -- to push beyond the 27 miles per gallon that new cars now average and the 20 miles per gallon for some sport utilities, minivans and pickup trucks. The overwhelming challenge in fuel efficiency is weight: lighter vehicles go farther on a gallon of gas.

When the federal Partnership for a New Generation Vehicle was signed into law in 1993, automakers weren't suffering from any illusions. They felt threatened by the new Democratic administration then being lobbied by environmental groups like the Sierra Club, who were demanding tougher federal fuel efficiency standards.

"We were careful never to use the word 'supercar,"' said Jim Johnston of the American Enterprise Institute. "That would have raised expectations."

The word came into use, however, and its image has proved irresistible to politicians, journalists and even to some auto executives.

The auto industry took to the project as a compromise that in effect would freeze fuel efficiency standards. Otherwise, even tighter fuel standards that environmentalists were demanding would have dictated that U.S. car makers shrink vehicles - especially high profit sport utilities, minivans and pickups just when the industry was recovering from a financial decline.

Environmental groups mistrusted the project, saying that the only way to achieve better gas mileage would be to impose tough standards and to let the auto industry figure out how to meet them.

The official goal was to develop the prototype for a midsize family car by 2004 that would be the same size as a conventional model. It would have about the same price and performance, meet safety and environ mental rules -- but provide "three times" aver age fuel efficiency, thus giving birth to the 80-miles-per-gallon mantra.

The federal budget's $794 million allocation was relatively modest, even in 1993 terms: The government was funneling more than 95 percent of the money to federal laboratories, much of it for pure research that was also of interest to the aerospace industry.

Last spring, General Motors, Ford Motor Co. and DaimlerChrysler AG each displayed high-mileage prototypes in Washington that were able to achieve more than 60 miles per gallon. The high-concept vehicles were impressive showcases for advanced technology. Unfortunately, none met current safety or environmental standards. And they were too expensive to build.

In other words, they were fascinating exercises that had little to do with the real world.

The Toyota Prius and Honda Insight, which employ hybrid systems, already get better than 50 miles per gallon with normal driving. Both models are a lot smaller than the typical family car, though they have found a niche market in the United States.

Ford, GM, DaimlerChrysler and others promise to introduce new technologies in the coming decade that could improve current mileage up to 40 percent, approaching 35 miles per gallon. Key technologies include fuel cells and hybrids that join battery-powered electric motors with small internal combustion engines.

Doron Levin is a columnist for Bloomberg News.