Safe cars versus fuel efficiency? Not so fast.

As Congress eyes a boost to fuel-economy standards, auto industry hints that safety could be compromised. Some experts disagree.

In a high-stakes showdown over proposed fuel-efficiency standards, the auto industry is playing its ace: the "safety" card.

In radio ads and over the Internet, it's pushing a message that implies that tougher standards will force automakers to make smaller and lighter cars that are not as crashworthy as today's less efficient models.

That's a message that has worked before. But this time, as Congress is set to begin debate Wednesday over whether to boost Corporate Average Fuel Economy (CAFE) standards for new cars and light trucks, some experts are not sure the argument holds water. Recent research suggests that new technology can make small cars safer and guzzlers more efficient. Some fuel-efficient cars are already safer than bigger, less less-efficient counterparts, a new study finds.

"There's no reason that higher fuel-economy standards would force automakers to change the size of the vehicle, [its] structural integrity or crash-worthiness," says David Greene, an Oak Ridge National Laboratory researcher and co-author of the study released last Thursday by the International Council on Clean Transportation. "It's unfortunate that manufacturers are trying to cast the debate in that way."

Instead, technology can help make cars and trucks lighter and more efficient without compromising their safety, says the report, which reflects a number of peer-reviewed studies in the past four years.

EASY FIXES: CRUMPLE ZONES, AIR BAGS

Today's cars can be designed with crumple zones to absorb shock and to encompass occupants with high-strength steel or aluminum. Lowered bumper beams, window-curtain air bags and other features could boost safety with little impact on weight. At the same time, 6-speed automatic transmissions, lower-rolling resistance tires, and other measures can boost efficiency without affecting size or safety, it says.

"The public, automakers, and policymakers have long worried about trade-offs between increased fuel economy in motor vehicles and safety," says the report cowritten by Dr. Greene; Tom Wenzel, a Lawrence Berkeley National Laboratory expert; and other independent researchers. "The conclusion of a broad group of experts is that no trade-off is required."

Environmentalists are latching on the report to bolster their argument that CAFE standards should be raised.

Automakers "say the only way to improve fuel economy is to produce tiny little cars the size of thimbles," says Daniel Becker, director of the Sierra Club's Global Warming and Energy Program. "But there's so many things that can be done without even making a car smaller from better aerodynamics to engine technology to better transmissions."

The Senate is expected to begin debating Wednesday a bill that would require automakers to meet a fleet-wide average fuel economy of 35 miles per gallon by 2020 – a 10 m.p.g. jump from today's combined standard for cars and light trucks. Thereafter, the standard would rise 4 percent a year through 2030.

Many experts say that making a car lighter makes it less safe.

The report "implies that if size is not reduced, then the mass can be reduced with no consequences," writes Russ Rader, a spokesman for the Insurance Institute for Highway Safety in an e-mail. "This is a willful ignorance of physics. The fact is that if a vehicle carries less energy in a collision, then it must be prepared to absorb more of that energy."

Small cars haven't fared well in the past, many safety experts say. They point to a key finding of a 2002 National Academy of Sciences report, which found: "Downsizing that occurred in the late 1970s and early 1980s, some of which was due to CAFE standards, probably resulted in an additional 1,300 to 2,600 traffic fatalities in 1993."

Auto-industry officials say the Senate legislation is "extreme" and suggest that it will force manufacturers to produce smaller vehicles.

"Study after study has confirmed that when meeting sharply increased fuel-economy standards, manufacturers are forced to make smaller, lighter, and less powerful vehicles – so safety trade-offs can be a consideration," says Wade Newton, spokesman for the Alliance of Automobile Manufacturers, a Washington-based trade association that represents General Motors, Ford, Daimler-Chrysler, Toyota, and other automakers.

Mr. Newton says the alliance is highlighting other issues, not just safety. He also confirms that the alliance has greatly expanded the number of radio spots beyond its original target of 10 states with large numbers of SUV owners.

Indeed, the idea of being forced to drive a smaller car when so many large SUVs prowl the roads could provoke a visceral public response.

RADIO SPOTS FEATURE WORRIED MOMS

In one radio spot, voices depict two SUV-loving soccer moms. One worries that "Congress is about to pass a law that's going to make it harder and harder to find" and purchase bigger vehicles. Then she adds: "Automakers are going to be forced to build smaller and smaller cars."

"I'm all for better fuel economy," her friend responds. "But for me, safety is my top concern."

Such pitches have spilled onto the Internet, too.

"Rather than letting the experts at the National Highway Traffic Safety Administration decide what standard is technologically feasible, the legislation mandates a standard that could compromise safety," says a new website created by the alliance, which encourages motorists to e-mail Congress.

Not all automakers are sending up red flares, however. American Honda Motor Co., the US division of Japanese maker Honda, has done at least four recent studies on the size, weight, and safety of vehicles and concludes design and technology are the most critical issues.

"It is certainly possible to put out fuel-economy requirements so stringent that automakers would have no choice but to downsize vehicles," says John German, manager of Environmental and Energy analysis for Honda Motor. "But if you do the fuel-economy requirements in any reasonable kind of manner, there shouldn't be any safety impacts."