In 2000, Congress passed the Transportation Recall Enhancement, Accountability, and Documentation (TREAD) Act. Section 13 of this act directed the U.S. Department of Transportation to complete a rulemaking within one year. This rulemaking requires implementation of a warning system in new motor vehicles (to be phased-in beginning with model year 2003) to indicate to the operator when a tire is significantly underinflated.

In support of rulemaking activities mandated by Section 13 of the TREAD Act, the National Center for Statistics and Analysis of the National Highway Traffic Safety Administration has completed an intensive data collection effort on the state of America’s tires. The Tire Pressure Special Study (TPSS) was designed to assess to what extent passenger vehicle operators are aware of the recommended tire pressures for their vehicles, the frequency and the means they use to measure their tire pressure, and how significantly the actual measured tire pressure differed from the manufacturer’s recommended tire pressure. Measurements were taken and interviews were conducted to compile a rich database of over 11,000 passenger vehicles (44,000 tires).

This paper will discuss the methodology of the TPSS as well as the extent of under-inflation found in the field and the attitudes and maintenance habits of drivers.