Posted by Matthew Yu on Fri, Nov 20, 2009 @ 12:32 PM
Most late model vehicles are equipped with Tire Pressure Monitor System (TPMS) on their tires to alert drivers whenever the tire pressure(s) drop below a certain percentage. However, due to weather and climate fluctuations, these TPMS lights frequently and may create unnecessary troubles for the vehicle owner. 
Fortunately, Nitrogen inflated tires will reduce this "false" alarm (at least its frequency).
Since under-inflated tires had been posing serious threat to the vehicle safety, the US National Highway Traffic Safety Administration (NHTSA) mandated all vehicles on or after MY2008 are required to be equipped with some sort of tire pressure monitor systems. While the TPMS definitely improves the safety of the vehicle by informing driver of potential loss of tire pressure, some TPMS systems may be so sensitive that they trigger the warning lights (typically 10% under-inflated levels) on the dashboard so easily. These TPMS triggers are usually caused by the temperature swing during the day. According to Get Nitrogen Institute, for approximately every 10 degree change in ambient temperature (+ or -), the pressure (in psi) will be affected about 2%. Simply speaking, if a tire is filled to 32 psi at 75 F and temperature drops 30 F (not uncommon in some areas), the tire pressure will drop to 30 psi, a difference of 2 psi. Since air is expected to leak out to atmosphere from the tire over time, it is not hard to imagine TPMS can present a problem for the driver.
Since Nitrogen migrates through a tire 3-4 times slower than regular air, TPMS alarms will not go off as often. Secondly, Nitrogen is a dry gas which does not contain moisture or dirt like air often does, so tire pressure remain relatively consistent. In addition, Nitrogen is less reactive than oxygen (in air) chemically. Removing oxygen prevents the oxidation (with the presence of moisture and dirt) which can attack expensive TPMS sensors. 
Coupled with other benefits like better tire pressure retention, improving fuel economy, enhanced safety, longer tire life, better vehicle handling and better environment, Nitrogen should be used for all vehicles equipped with TPMS.