Oil Consumption is Rising, Imports are Skyrocketing, and Our Vehicles Are to Blame

More Efficient Conventional Vehicles

American vehicles produced today get just 20.8 miles to the gallon, on average -- lower than in the 1980s. But studies by the National Academy of Sciences, the nonprofit American Council for an Energy Efficient Economy and other independent analysts show that automakers could use existing technology to raise average mileage for new vehicles to nearly 40 mpg over the next 10 to 15 years while maintaining or improving safety.

Car companies have developed a host of technologies that make vehicles vastly more efficient. Some examples:

• Engine improvements
  Four-valve cylinders - More valves allow the engine to work more efficiently. These engines are standard in most cars and smaller SUVs, but not offered in most medium and large pickups and SUVs.

  Variable valve timing - This advance increases torque, improves fuel efficiency, and decreases pollution.

• Better aerodynamics and lightweight materials
  Improved design can significantly reduce drag, saving fuel. Aluminum or high-strength steel can reduce the weight of vehicles, while maintaining their size and strength and maintaining or improving safety.

• Automatic shut-off and cylinder deactivation
  New technologies can shut off the engine at stoplights (restarting instantly), or shut down extra cylinders when the car is cruising.

  Auto-stop is available now on some GM pickups; cylinder deactivation (or "displacement on demand") is coming soon from GM and Honda.

• Enhanced transmissions
  Five- and six-speed transmissions - More gears equal better performance and better fuel economy.

  Continuously variable transmissions - Some new automatics do away with gears altogether, saving gas with a continuous power band. This technology exists for cars and smaller SUVs, and can be adapted for bigger trucks.

Who's making them?

Many automakers are employing some of these new technologies in some models. For example:

• Sixty percent of the cars and trucks Honda sells in the United States use its "VTEC" engine, which uses variable valve control. Honda leads all manufacturers in fleet-wide fuel economy.

• GM has designed an aluminum four-valve overhead cam engine, which became available with several 2002 models, including the Chevrolet Cavalier and Oldsmobile Alero. Its modular design allows for variable valve timing.

  GM is also moving forward with its "displacement on demand" or cylinder-cut-off engines, which turn 8-cylinder engines into 4-cylinders when the power's not needed.

• The Ford Explorer uses a five-speed automatic transmission.

• Continuously variable transmissions have been available for years in versions of the Honda Civic HX. Audi has also offered a CVT version of its A6 car since 1999.

So what's the problem?

In some cases, automakers are taking a toe-in-the-water approach, when Americans want them to jump in: according to an ABC/Washington Post poll, 81 percent of Americans strongly support more fuel-efficient vehicles.

And some technologies are commonly used in small and mid-size cars, but not in SUVs. Automakers have had no incentive to improve SUVs because of a loophole in the law that exempts many "light trucks" from the more stringent fuel efficiency rules that apply to passenger cars. (The loophole was written long before SUVs became common passenger vehicles and was intended to apply to work vehicles.)