"Tires that are underinflated by just six to seven pounds per square inch can reduce vehicle fuel economy by as much as 2 percent and tire tread wear can also be reduced by as much as 10 percent," says Mark Chung of Yokohama Tire Corporation, which manufactures tires for passenger cars, SUVs, buses, trucks and airplanes. "Correct tire inflation pressure also reduces tire fatigue which maximizes the tire's service life."

The National Highway Traffic Safety Administration (NHTSA) reports 66 million vehicles have underinflated tires, which literally means more rubber is hitting the road and, accordingly, miles per gallon is lessened. "With an average of 12,000 miles driven annually on tires that are underinflated by five to eight psi, and a vehicle average of 22 miles per gallon, tire experts speculate that about 726 million gallons of gas are wasted annually by U.S. drivers simply because they're driving on underinflated tires," says Chung.

At today's gas prices of as much as $3.65 per gallon (in California), 726 million gallons of gas translates to a staggering $2.6 billion lost by consumers for having underinflated tires.

"In addition, those 726 million wasted gallons result into 14,520,000,000 pounds of carbon dioxide released into the environment," Chung says. "We can all help prevent this by making sure our tires are properly inflated."

People can find the tire's proper inflation level on the vehicle placard located in the driver-side-door jamb, in the glove box or in the owner's manual. While there are about 3,500 sizes and types of tires on the market, Chung has some simple tips to aid proper tire wear:

* Once a month, when the tires are cold -- at least 3 to 4 hours after the vehicle has been driven -- check tire pressure with a reliable tire gauge. Normal driving causes tires to heat, which raises air pressure. Be sure that the valve stems have a plastic or metal cap to keep out dirt and seal against leakage.

* Tires should be rotated at least every 6,000 to 8,000 miles and vehicle alignment should be checked once a year. Misalignment can cause the tire tread to slip and abrade, which lowers fuel mileage and causes unnecessary tire wear.

* An overinflated tire changes and increases wear on the center of the tread, whereas an underinflated tire increases shoulder wear. A tire is designed to run with the vehicle's weight spread correctly in the road contact zone.

For more information, visit www.yokohamatire.com/csunderstand.asp for additional tire care and safety tips, the Rubber Manufacturers Association's Web site at www.rma.org and AAA Club at www.aaa.com.

"With escalating fuel prices, drivers are going to focus on simple things like proper tire pressure to maximize tire performance, increase fuel economy, help the environment and boost tread wear," says Chung. "Keep your tires properly inflated and you'll prevent your wallet from being deflated."