This report is an analysis of the data collected through the Tire Pressure Monitoring System-Special Study as it pertains to the effectiveness of TPMS in promoting proper tire inflation. The study was conducted in 2011, using anationally representative sampling structure, based on the primary sampling units (PSUs) of the National Automotive Sampling System. NASS personnel collected 6,103 complete vehicle observations including tire pressure of all four tires. This survey found that 23.1 percent of the MY 2004-2007 vehicles without TPMS had at least one severely underinflated tire as defined by FMVSS No. 138 (25% or more below the vehicle manufacturer’s recommended cold tire pressure), but only 11.8 percent of the MY 2004-2007 vehicles equipped with TPMS had a severely underinflated tire. Based on these results, the presence of TPMS on a vehicle of model years 2004 to 2007 is estimated to result in a 55.6-percent reduction in the likelihood that the vehicle will have one or more severely underinflated tires as defined by FMVSS No. 138. It is also estimated to result in a 30.7-percent reduction in the likelihood that the vehicle will have one or more tires that are overinflated by 25 percent or more above the manufacturer'srecommended cold tire pressure. During the first eight years of operation TPMS is estimated to save a typical passenger car 9.32 gallons of fuel and a typical LTV 27.89 gallons of fuel. During 2011 TPMS is estimated to have saved $511 million across the vehicle fleet through reduced fuel consumption. NHTSA plans to conduct further research to determine the effect of TPMS on the incidence of tire?related crashes and injuries. (Author/publisher)
Samenvatting