It is possible. And it won't require hydrogen fuel cells, second-generation hybrids, or other cutting-edge options that will take years to scale up. Auto makers have a bag of well-rehearsed tricks that can be easily integrated into today's designs. Put them together, and they have the potential to achieve a mileage revolution. "Few auto makers have bothered to combine these things yet," says David Friedman, research director at the Union of Concerned Scientists, a nonpartisan Washington advocacy organization.
The key is integrating a variety of off-the-shelf technologies to make lighter, more aerodynamic vehicles powered by smarter engines and transmissions -- without sacrificing speed, safety, or vehicle size. It may sound pie-in-the-sky, but mileage gains of up to 30% are possible at a reasonable cost, according to studies by UCS in 2003 and the National Academy of Sciences in 2002. Sport-utility vehicles and trucks would benefit most, but cars and minivans have room to improve, too.
Buyers are already beginning to vote with their pocketbooks. In August -- before Katrina and despite U.S. carmakers' summertime "employee discount" blitz -- the sales share of large SUVs and trucks fell by two percentage points, to 3.8%. "It's difficult to find such a rapid fall in such a short period," says Jesse Toprak, a senior analyst at Edmunds.com. Meanwhile, the share of compact cars sold rose to 17%, from 14.5%. "With a big consumer shift, auto makers will have to focus on matching existing technologies to optimize gas mileage," he adds.
Trends abroad are adding pressure. Regulators in China, Japan, and Europe have continued to raise mileage standards. Indeed, in a 2004 study by the Pew Center on Global Climate Change that normalized mileage rules in top auto markets, U.S. rules ranked dead last, and the gap will only widen as scheduled hikes overseas take effect. If carmakers don't meet those standards, it will crimp future sales. China, for example, is destined to be the world's largest car market, and Detroit wants a big piece of the action. Yet Beijing recently unveiled mileage goals that are 22% more demanding than today's U.S. levels, and should be 35% stricter still come 2008.
For carmakers eager to satisfy the wishes of economy-minded customers and regulators, there are plenty of options. The following technologies could boost mileage without sacrificing size or safety or breaking the bank.1 LIGHTER MATERIALS For every 10% drop in weight, mileage improves by around 5%. One way is by combining body and frame elements into a simplified "unibody." That can boost mileage by 8%. For bigger gains, some companies are substituting costlier aluminum or high-strength steel. These materials are now being used more to boost performance than efficiency. Ford Motor Co.'s Jaguar division trimmed over 400 pounds from the XJ sedan partly by using aluminum in the frame. This yields better mileage from a somewhat smaller engine that can still keep pace with competing sedans. Combining these two approaches, while not cheap, could theoretically boost mileage in SUVs by up to 30% for less than $1,000, estimates UCS.2 DRAG REDUCTION Friction is a mileage killer. First, there's rolling resistance from tires on the ground. Keeping tires properly inflated is one of the easiest ways to improve mileage today by up to 3%. Remote tire sensors -- mandated after the Ford-Firestone debacle -- will go part of the distance, as will improved tire designs that can run at higher pressures without sacrificing comfort.
Even minor reductions to aerodynamic resistance can bring benefits. Honda Motor Co.'s () Pilot SUV is nearly as slippery as a car, largely because Honda rearranged components to smooth out its underbelly. The change was cheap, since it involved no new material. Getting rid of side-view mirrors is a possibility, too, thanks to the imminent introduction of tiny low-cost video cameras and displays on the inside of the car. For $180, figures UCS, SUV drag could be cut enough to boost mileage by up to 6%.3 SMARTER ENGINES The motor remains the heart of the car -- and still the source of potentially big efficiency gains, even after a century of evolution. Today's engines are digitally controlled wonders, served by sensors and electronics dedicated to boosting performance. Japanese carmakers have led the high-tech push, with advanced valve-timing-control technologies that minutely vary the flow of oxygen and gas into the cylinder. In the latest tweak of its flagship engine, Honda's i-VTEC eked out 6% more efficiency.
U.S. auto makers are squeezing out savings from older "pushrod" engine designs. Both GM () and Chrysler Group () sell models that shut down unneeded cylinders at highway speeds, when less power is needed to keep cruising. For GM, the approach boosts fuel efficiency by about 5% at an estimated cost of $50 per vehicle.4 STARTER GENERATOR About 15% of gas is wasted when a car's engine idles during stops. By relying on superfast sensors and controllers, gas engines can be completely shut off at idle and switched on again faster than a driver can move from the brake to the gas pedal. The key is a "starter-generator" electric motor that spins the engine back to speed. GM put this technology on its GMC Sierra and Chevy Silverado hybrid pickups, contributing to mileage gains of about 10%.5 SIX-SPEEDS Each additional gear widens the range of speeds at which an engine achieves maximum efficiency. So while 4-speed transmissions are good, 5-speeds are better. Even 6-speed gearboxes are no longer exotic. More than six is unlikely in the mass market, says Edmunds.com's Toprak, but going from 4- to 6-speeds can yield mileage gains of up to 7%. As production volumes grow and costs fall, 6-speed transmissions will become the norm.
None of these options is a cure-all. Then again, the search for a single magic solution to fuel savings will only delay adoption of incremental innovations. If combinations of these techniques can deliver a 30% mileage improvement, SUVs that get 15 mpg now could soon get 19.5 mpg. With gas at $3 per gallon, that difference would cut fuel costs for a 15,000-mile year by $700. Consumers are calculating the value of such savings -- and showing a willingness to pay for them up front. By Adam Aston in New York