TWO cars in the garage: one, a Ford Explorer that climbs mountains like a billy goat but guzzles fuel; the other, a Subaru that is far less thirsty but more wimpy on the road. The driver pauses, then climbs into the huskier auto. It's more fun, even for a trip to the post office.
It's a choice made daily, not just in the mountainous West, but in cities and suburbs across the country.
Gasoline is plentiful and cheap. And Americans in droves - the ''oil shocks'' of the '70s a distant memory - are buying light trucks, minivans, and four-wheel-drive vehicles with an off-road image.
These now constitute more than 40 percent of all new vehicle purchases in the US. The trend is one reason progress on improving fuel-mileage figures has stalled, reviving the debate over whether the government should push car manufacturers for further improvements or back off.
More than 60 members of Congress are sponsoring legislation that would freeze Corporate Average Fuel Economy (CAFE) standards at current levels. CAFE standards for 1996 are 27.5 miles-per-gallon for autos and 20.7 m.p.g. for light trucks.
''Our bill ... means more choice, more jobs, more economic growth, and simply more common sense,'' says Rep. Fred Upton (R) of Michigan (who drives a late-1980s Pontiac Sunbird and has an even older Jeep back home). ''Who can really argue with that?''
Arguing with that are environmentalists, energy-policy reformers, and some federal officials who maintain that the 20-year-old CAFE program has meant fewer oil imports than would otherwise have been the case and cleaner air without sacrifices to auto performance or safety.
''There can be no doubt about the energy-conservation effects of improved fuel economy levels,'' Barry Felrice, associate administrator of the National Highway Traffic Safety Administration (NHTSA), told a congressional panel in July. ''If the average fuel economy of all passenger cars in today's fleet were the same as 1975's fleet, we would consume a billion more barrels of oil each year.''
And since each gallon of fuel creates 19 pounds of carbon dioxide (the major ''greenhouse'' gas tied to global warming), the reduced fuel use produces a lot less pollution as well.
Push for higher standards
In response to the sharp increase in less-efficient light trucks and similar vehicles, the Department of Transportation has said it will consider pushing fuel standards higher for such vehicles. While no specific numbers have been proposed, officials note a 1992 National Academy of Sciences report suggesting a ''technologically feasible'' level of 26 to 28 m.p.g. in 10 years.
In a recent letter, members of Congress (including House minority leader Richard Gephardt of Missouri) warned that that move ''would have a disastrous long-term effect on Chrysler, Ford, and General Motors.'' As the auto industry and its allies see it, the problems with CAFE are that it gives foreign imports a competitive advantage while failing to meet shifting consumer demand.
The Environmental Protection Agency (EPA) this week released fuel-economy ratings for 1996 model year cars and light trucks. In general, new cars have achieved twice the gas mileage since CAFE standards were imposed, and fuel economy for light trucks has gone up about 50 percent.
But if the coming year follows recent trends, top 10 fuel-efficient cars will account for less than 1 percent of those sold.
''Most consumers consider safety, utility, and durability more important than fuel economy,'' says Diane Steed, president of the Coalition for Vehicle Choice (an industry lobbying group) and former NHTSA administrator. ''According to consumer polling data, fuel economy ranks 15 among ... reasons for purchasing [a car or truck.] In 1980 fuel economy rated No. 2.''
Are smaller cars less safe?
According to the Insurance Institute for Highway Safety, large vehicles with more ''crush distance'' have fewer occupant deaths than smaller cars. ''Both weight and size are important, and those who claim that either one needn't be prominently considered when it comes to safety in the future are, in effect, claiming that the laws of physics can be repealed,'' says Brian O'Neill, the organization's president.
NHTSA official Mr. Felrice acknowledges this. But on balance, he adds, ''the safety advances of the last 20 years, including the installation of air bags and the increased usage of safety belts and child safety seats, have more than offset the negative effects of smaller size.
''The overall fatality rate is presently 1.7 per 100 million vehicle miles traveled, exactly one-half the rate in 1975, despite a passenger car fleet that is, on average, nearly a thousand pounds lighter than the 1975 fleet,'' he told lawmakers.
Automakers also argue that m.p.g. figures have been raised about as high as they can, given current technology - especially for the light trucks, minivans, and sport-utility vehicles consumers favor.
''Already, the truck fleet has sophisticated electronics, fuel injection, and lighter-weight materials,'' says Andrew Card, president of the American Automobile Manufacturers Association.
Others say applying existing technology to more cars - even bigger ones - could make a real difference in fuel economy.
The Center for Auto Safety and the Sierra Club contend that the best-selling car in America - the Ford Taurus - could dramatically boost its m.p.g. rating with several changes: shifting to a 1.8-liter, multivalve engine with variable-valve timing (which burns fuel more efficiently) and a five-speed automatic transmission; using better lubricants; and improving aerodynamics.
''If the Ford Taurus used the same technologies that the Honda Civic VX uses, it would go from 27.5 miles-per-gallon to 42.5,'' says Daniel Becker, director of the Sierra Club's global warming and energy program.
In their study of existing and emerging technologies, John DeCicco and Marc Ross of the American Council for an Energy-Efficient Economy concluded that fleet fuel economy in the year 2001 could be as high as 45 m.p.g. - a 60 percent increase over the 1990 base year figure of 28 m.p.g.
'Car talks' stall
While Congress wrestles over the future of the CAFE program, a special presidential panel has fractured over the subject of government-set fuel-economy standards.
A year ago, President Clinton named the Personal Motor Vehicle Greenhouse Gas Reductions Advisory Committee (dubbed ''Car Talks''). Its 30 members include automakers, oil producers, environmentalists, consumer advocates, and an assortment of state and local officials.
During the group's final meeting two weeks ago, auto industry representatives refused to consider any increase in CAFE standards, pushing instead for a $1.50-per-gallon gasoline tax to be phased in at five cents a year over the next 30 years.
Oil producers rankled at a steep gas tax, which presumably would have cut into their business. Environmentalists (who say the gas tax proposal is just a ploy) refused to consider any report to the president that did not include CAFE measures.
As a result, the environmentalists, consumer advocates, and public officials are scrambling to put together their own report before the committee is scheduled to expire in three weeks.