WASHINGTON — Mixed in with the tourists on Capitol Hill recently were young people in green uniforms with the word "Drive" emblazoned on their chests, holding out a steering wheel in their best pretend-drive fashion.

If passers-by were curious enough to ask, the Drivers were ready with an answer: They represent owners of alternative-fuel vehicles.

The stunt was courtesy of the Alliance of Automobile Manufacturers, part of its "Discover Alternatives" advertising campaign that targets lawmakers and their staffs while promoting the industry's work on ethanol and other biofuels.

The ad campaign has helped power a bandwagon for ethanol in Washington that has steadily attracted supporters in recent weeks, fueled by concerns over high gasoline prices and increasing dependence on foreign oil. But the attention paid to ethanol has also shut down any debate over raising fuel economy standards, something environmentalists argue was by design.

Ethanol has "definitely been put out there as a head-to-head competitor and seen by some as a replacement for fuel economy," said Roland Hwang, the senior policy analyst at the Natural Resources Defense Council. "It's not the way our community sees it."

Don Mackenzie, vehicles engineer with the Union of Concerned Scientists, said it could take years to build up the ethanol industry enough to have a noticeable impact on oil demand.

"In the near term, we can do a lot more with fuel economy than we can with ethanol or any other biofuel," Mackenzie said. "There are limits to how quickly you can build up a new industry."

The vast majority of gas-ethanol mix sold in the country is 10 percent ethanol, which works in any vehicle. Ethanol proponents favor E85, a blend of 85 percent ethanol and 15 percent gasoline. So far, E85 is only available at fewer than 800 filling stations around the country.

But Detroit automakers have fully embraced E85 as a way to burnish their environmental image and to deflect questions about fuel economy amid near-record gas prices.

General Motors Corp., Ford Motor Co. and DaimlerChrysler AG have agreed to double their production of E85-capable vehicles to 2 million annually by 2010.

When asked two weeks ago about worries over fuel economy, Chrysler Group Chief Executive Tom Lasorda cited the company's new four-cylinder engines and its pledge to build 500,000 vehicles next year that can run on either E85 or regular gas.

"We're providing alternative fuel for oil independence for this country, as well as good fuel economy," Lasorda said.

The automobile manufacturers alliance, which includes GM, Ford, DaimlerChrysler, Toyota Motor Corp. and Nissan Motor Co., contends in its campaign that the industry has built 8 million vehicles with alternatives to traditional gasoline engines, including hybrids, diesels and engines that can burn E85.

"We felt we should talk about the number of alternative-fuel automobiles on the road, with the price of gas being a concern to consumers and the increased focus on energy security," said alliance spokesman Charles Territo.

"We wanted to let members of Congress know that these aren't just vehicles we talk about. These are vehicles that are on the road today."

The auto industry has a cadre of allies in its drive to boost ethanol. Corn growers have long advocated ethanol use, which boosts demand for their crops.

Rural lawmakers see jobs for communities that have lost employment to larger cities. And many lawmakers embrace the idea that ethanol can reduce U.S. energy dependence on unfriendly or unstable foreign regimes.

President Bush has mentioned ethanol several times in the last few months as part of his energy program, which includes pushing for more refinery capacity and research into plug-in gasoline-electric hybrid vehicles.

The bill containing his proposal has stalled in the House, and neither chamber of Congress is expected to address the issue before the November elections.