Aircraft have been running nitrogen in the tires for years due to the temperature / expansion thingy .......... teh suggestions for use on everyday passenger vehicles is a sound notion - although a little noisy - on the pocket book. Nitrogen isn't commonly available, and the cost of topping tires off with Nitrogen versus checking tire pressure every tank or even 2nd tank with plain old compressed air ...... well, won't take a genius to compute the savings there.

Sure, more evenly maintained tire pressure for slightly improved gas mileage, but the environmental impacts of processing air into Nitrogen outweigh any gas mileage savings.

Just another money grabbing gimmick.