I. INTRODUCTION

This Final Economic Assessment analyses the National Highway Traffic Safety Administration’s new Federal Motor Vehicle Safety Standard (FMVSS) No. 138 that requires a tire pressure monitoring system (TPMS) on all passenger cars, light trucks (pickups, vans, and sport utility vehicles), and buses with a gross vehicle weight rating (GVWR) of 10,000 pounds or less (collectively this group is called "passenger vehicles" throughout this assessment). This is in accordance with the TREAD Act (H.R. 5164), Sec. 13. Tire Pressure Warning: "Not later than 1 year after the date of the enactment of this Act, the Secretary of Transportation shall complete a rulemaking for a regulation to require a warning system in new motor vehicles to indicate to the operator when a tire is significantly under-inflated. Such requirement shall become effective not later than 2 years after the date of the completion of such rulemaking." This means that the final rule must be effective on November 1, 2003. The agency issued the NPRM on July 26, 2001 (66FR 38982). The docket number is NHTSA-2000-8572. The NPRM is at docket no. 8572-28. The "Preliminary Economic Assessment, Tire Pressure Monitoring System, FMVSS No. 138" July 2001 is at docket no. 8572-57.

The Decision

During the phase-in period (November 1, 2003 to October 31, 2006), a manufacturer can comply with one of two compliance options. Under the first compliance option, a vehicle’s TPMS must warn the driver when the pressure in any single tire or in each tire in any combination of tires, up to a total of four tires, has fallen to 25 percent or more below the placard pressure, or a minimum level of pressure specified in the standard, whichever pressure is higher. Under the second compliance option, a vehicle’s TPMS must warn the driver when the pressure in any single tire has fallen to 30 percent or more below the placard pressure, or a minimum level of pressure specified in the standard, whichever pressure is higher.

To help provide additional data on the performance and effectiveness of TPMSs, NHTSA plans to conduct a study comparing the tire pressures of vehicles without a TPMS to the tire pressures of vehicles equipped with a TPMS that does not meet a four-tire, 25 percent compliance option. The agency will arrange for a peer review of the study methodology and of the study results, including the safety significance of any differences in tire pressure between the two groups of vehicles. If sufficient data are available, the agency also will assess the performance and effectiveness of TPMSs that do meet a four-tire, 25 percent option. The study will be completed by March 1, 2004. The agency also will leave the rulemaking docket open for the submission of new data and analyses concerning the performance of TPMSs.

The agency will issue the long-term (i.e., for the period beginning November 1, 2006), performance requirements by March 1, 2005.

Based on the record now before the agency, NHTSA tentatively believes that the four tire, 25 percent option would best meet the mandate in the TREAD Act. However, it is possible that the agency may obtain or receive new information that is sufficient to justify a continuation of the options established by this first part of this rule, or the adoption of some other alternative.