And yes, lest there be any doubt, we are talking the same perfectly safe nitrogen that comprises 78 percent of the air we breathe.

Here’s how the savings kicks in: The U.S. Department of Energy estimates that Americans waste as much as 1.2 billion gallons of fuel each year due to underinflated tires.

But nitrogen diffuses through tire rubber about 40 percent more slowly than air, helping the tire maintain pressure longer. Proper pressure means reduced rolling resistance-which maximizes gas mileage.

What’s more, since a well-inflated tire is less susceptible to wear-which explains the race car angle-you can wind up saving even more money by not having to replace your tires as often.

So where can you fill up your tires with nitrogen? At many auto-care centers nationwide, according to Ashok Mathur of Air Products, a company that makes the Ultra- Fill High-Purity Nitrogen Tire Inflation System. “Nitrogen works with any grade of existing tire, as the air can be purged out and the tire reinflated with nitrogen,” he says.

Plus, Mathur says the high-purity nitrogen his system produces maximizes the advantages of nitrogen tire inflation even further.

“The gas provides for a safer, smoother ride because optimum tire pressure increases vehicle handling and control,” he says.

Two added benefits to nitrogen: fewer stops at the gas station to top off the air in tires; and if you ever have a flat tire, a spare filled with nitrogen is more likely to be ready to roll than one filled with air.

But Mathur says that for many people the decision to use nitrogen boils down to dollars and cents. “If your tire is underinflated by just 20 percent, you can lose up to three miles per gallon,” he says. “Those miles add up quickly. And that’s why nitrogen is becoming so popular.”

For more information, visit www.ultrafill.com.