Why under Inflated Tires are a Road Safety Hazard
Low tire pressure is dangerous at certain levels of under-inflation according to the National Highway Traffic Safety Administration. When tire pressure becomes deflated too much, it substantially effects vehicle maneuverability, tire capacity and tire stress. Moreover, under-inflated tires raise internal tire air temperature and increase rolling resistance. These effects in turn lead to a higher risk of vehicular accidents.
TheNHTSAtested the hypothesis under-inflated tires are a driving hazard using an experiment with varied levels of tire pressure under the same road test conditions. More specifically, tire pressures were reduced by more than 25 percent, 10-25 percent, and less than 10 percent to observe the effect on accidents. As might be expected, of the vehicles with tire pressures under-inflated by more than 25 percent of the recommended amount, a near 10 percent crash rate was recorded. This crash rate lowered to six and four percent with the reduced under-inflation.Low tire pressure also increase the chance of a tire blowout, which in turn increase the probability of an accident occurring. In a separateNHTSA report, it is stated this is because “When a tire is used while significantly under-inflated, its sidewalls flex more and the air temperature inside the tire increases, increasing stress and the risk of failure.” In other words, better inflated tires contribute to cooler air temperatures inside the tire and less pressure on the tire walls. This is corroborated by car experts published in theSt. Petersburg Times, and who state the increased wall pressure can cause the tread belt to tear off.Another reason lower tire pressure causes accidents is because rolling resistance is reduced in wet weather per the NHTSA. Moreover, this lowered rolling resistance leads to longer stopping times under rainy conditions which itself leads to accidents if drivers misjudge stopping time and space needed. In drier weather, lower-inflation leads to increased rolling resistance, which perAlternate Energy eMagzine, puts more pressure on the tire because it is more susceptible to deformation via driving. The NHTSA says, under-inflated tires also have less “tire load per area”, or lower weight capacity, which when combined with lower rolling resistance in wet weather causes accidents in some instances.Safety features such as tire pressure monitoring systems on newer vehicles, state safety inspections and individual monitoring of tire pressure help reduce the occurrence and extent of low tire pressure. Adjusting tire pressure according to individual manufacturer and vehicle guidelines is also prudent. When pounds of pressure per square inch or PSI numbers on the tire is different from the recommended PSI for the vehicle,Car Talksuggests not confusing the two, and sticking to the vehicle manufacturer value.
