Seeking a brief, warm-weather respite from the overheated yelping of politicians, we have become intrigued with the latest automotive commodity, guaranteed to, well, you decide…

No, it is not the formula for fueling your vehicle of choice with Red Bull or a derivative of dehydrated broccoli, although the latter would please us no end, if only to find a use for that stuff other than in restaurants where we are actually paying to eat.

It is not a “smart car,” which is neither smart nor a car by any recognized meaning of either word. That’s just something along the lines of a bubble-top, big-wheel go cart powered by a sewing machine engine with a road safety factor of minus 330. It might be suitable for Obama voters or certified green people if the added off-center weight of the requisite bumper stickers didn’t make the thing go only in leftward circles.

It is not the Hybrid Tahoe, which several conservative talk show hosts have been extravagantly praising, largely perhaps, based upon free rides, yet to be bestowed upon the lowly among us.

No, dear hearts, the big new thing, at least in certain markets, is tires filled with nitrogen.

Nitrogen is not new in race car, airplane or spaceship tires. It’s not even really new for everyday transportation, but got little traction with consumers when gas was cheap. Come the new reality – when corn is worth more for that ethanol con than for moonshine, mechanics are recycling oil stains from their work clothes and the science of siphoning is being taught at community colleges – then people will try almost anything.

The theory in support of nitrogen-filled tires is fairly straightforward. Tires filled only with compressed air leak consistently and considerably. In addition, variations in heat cause pressure to expand and contract so optimum pressure is not constant. Oxygen, about 21% of air, degrades tires. Compressed air adds moisture inside tires, which isn’t real good for longevity.

Under-inflated tires are bad, for wear, for safety, for mileage. Over-inflated tires are bad. Goldilocks tire pressure, as stated on that tire or car sticker, is just right, but that is difficult to keep. Gas station air compressor gauges are notoriously inaccurate, so even if you are diligent about tire pressure, that is no guarantee of the consistently optimum pressure required. Couple that with drivers who don’t have a clue what their tire air pressure is and the result is about 30 percent of U.S. cars have one or more tires under-inflated by at least 8 psi. That’s considerable when most tires are properly inflated in the 30 psi range.

Proper tire inflation improves mileage by about 3.3 percent. Underinflated tires reduce mileage by 0.4 for every one psi drop in pressure of all the tires on the vehicle. That translates into about 144 gallons wasted a year for someone who drives 12,000 miles. Overall, it is estimated that U.S. drivers waste more than a billion gallons of gas a year solely as a result of under-inflated tires.

Enter nitrogen. Correctly filling tires with pure nitrogen seems to retard, but does not stop, leakage. Nitrogen is dry and clean and safe (contrary to the occasional internet idiot or provocateur, it cannot explode). Nitrogen doesn’t expand or contract with heat fluctuations. It does not degrade tires.

Without debating the numerous whys and wherefores, there seems to be something of a consensus that nitrogen-filled tires can provide at least some improvements in mileage, safety and tire longevity. It cannot hurt. If you can get it free or at marginal cost with a new car or new tires, with readily available, cost-effective refills, it’s worth a try. It’s at least a free-market attempt to solving a problem with which we are individually and collectively struggling. The key, with either air or nitrogen, is proper inflation and regular tire rotation.

Be advised, however, that nitrogen-filled tires come with bright green valve-stem covers, about which we shall reserve comment.