Another way Americans can cut oil demand is to buy conventional cars and trucks that get better mileage. Technologies to boost mileage on conventional cars exist, but they're not widely used, nor are they used in combination to further boost efficiency. Vehicles produced in the United States today get an average of about 20 miles to the gallon -- lower than in the 1980s -- but independent research shows that carmakers could use existing technology to raise average mileage for new vehicles to nearly 40 miles per gallon during the next decade.
Although 81 percent of Americans strongly support more fuel-efficient vehicles, according to an ABC/Washington Post poll, manufacturers are not meeting the challenge. Fuel-efficient technologies are often used in small and midsize cars, but not in SUVs, which along with pickup trucks accounted for more than half of the U.S. passenger vehicle market in 2006. Automakers have had little financial incentive to improve SUV efficiency because of a law that exempts many "light trucks" (a term intended to refer to work vehicles, not SUVs) from the more stringent fuel economy rules for passenger cars.
Today's Fuel Efficient Technologies
Off-the-shelf technologies that could get wider play include:
- Four-valve cylinders allow the engine to work more efficiently. They are standard in most cars and smaller SUVs, but not offered in most medium and large pickups and SUVs.
- Variable valve timing is an advance that increases torque, improves fuel efficiency and decreases pollution. Variable valve control is used in Honda's VTEC engine, which is found in 60 percent of Honda's U.S. cars; Honda's fleet is No. 1 overall in fuel efficiency. GM has designed an aluminum four-valve overhead cam engine that allows for variable valve timing. It became available with several 2002 models, including the Chevrolet Cavalier and the Oldsmobile Alero.
- Automatic shut-off and cylinder deactivation technologies can shut off the engine at stoplights (to restart instantly when needed) or shut down extra cylinders when the car is cruising.
- Five- and six-speed transmissions provide more gears for better performance and fuel economy. New continuously variable transmissions do away with gears entirely, saving gas with a continuous power band. This technology has been used for years in some Honda and Audi models; it can be employed in cars and smaller SUVs, and can be adapted for large trucks.
- In addition to the many improvements possible beneath the hood, better aerodynamic design and lighter-weight materials can reduce drag and save big on fuel. Aluminum or high-strength steel can reduce the weight of vehicles without sacrificing safety.