A Commented Synopsis of the Report of the Committee for the National Tire Efficiency Study4
The Congress of the United States petitioned the Transportation Research Board of the National Academy of Sciences to study replacement passenger car tire rolling resistance in 2005 with funding from the National Highway Traffic Safety Administration. The study was initiated to assess the potential for reduction in replacement tire rolling resistance to yield fuel savings. The time required to realize these savings is less than the time required for automotive and light truck fleet replacement. Congress recognized that other factors besides fuel savings had to be considered if the committee’s advice was to be a reasonable guide for public policy. Therefore, the study simultaneously considered the effect of potential rolling resistance reductions in replacement tires on fuel consumption, wear life, scrap tire generation, traffic safety, and consumer spending for tires and fuel. This paper summarizes the committee’s report issued in 2006. The authors, who were members of the multidisciplinary committee, also provide comments regarding technical difficulties encountered in the committee’s work and ideas for alleviating these difficulties in further studies of this kind. The authors’ comments are clearly differentiated so that these comments will not be confused with findings, conclusions, and recommendations developed by the committee and contained in its final report.Abstract

CAFE history [5].

Fuel saved by a 5 mpg increase in average fuel economy plotted as a function of the initial fuel economy level.

Average distribution of energy for a four-cylinder sedan in both the urban and highway CAFE cycles [6].

Example rolling resistance coefficients for tires from data provided courtesy of the Rubber Manufacturers Association.

RRC to UTQG tread wear grade correlation for the 196 tires in the RMA data set. The Rubber Manufacturers Association provided this data set to the committee. The data are available through TRB.

RRC to UTQG tread wear grade correlation for 15 in. rim sized s and t speed rated tires in the RMA data set. The Rubber Manufacturers Association provided this data set to the committee. The data are available through TRB.

RRC versus UTQG wet traction grade, combined Ecos, and RMA data.