摘要: |
Public Law 106-346 (Department of Transportation and Related Agencies Appropriations Act, 2001) requires the U.S. Department of Transportation to fund a study by the National Academy of Sciences on "whether the static stability factor [SSF] is a scientifically valid measurement that presents practical, useful information to the public, including a comparison of the [SSF] test versus a test with rollover metrics based on dynamic driving conditions that may induce rollover events." To respond to the congressional study request contained in Public Law 106-346, which came through the National Highway Traffic Safety Administration (NHTSA), the Transportation Research Board of the National Research Council formed the Committee for the Study of a Motor Vehicle Rollover Rating System. The committee undertook three main tasks: (1) a comparison of the information provided by the SSF static metric with that obtained from tests of dynamic vehicle performance; (2) an assessment of whether SSF is a valid measure of vehicle rollover propensity, as indicated by the involvement of vehicles with a range of SSF values in actual rollover crashes; and (3) an assessment of whether vehicle test results, both static and dynamic, can be interpreted and used by consumers in making informed decisions about vehicle purchases. The committee's findings are presented in this special report. Chapter 1 provides an introduction. The vehicle dynamics of rollover is described in Chapter 2, which also includes discussion of static measures and dynamic vehicle testing. The chapter also includes comments on the relevance of electronic stability control systems to rollover, in response to a request from NHTSA. Chapter 3 presents the committee's review of the statistical analyses used by NHTSA as the foundation for its five-star rating system for rollover resistance. Statistical analyses of rollover crash data have been conducted by Exponent Failure Analysis Associates, Inc. at the request of the Alliance of Automobile Manufacturers. The committee has considered these studies within the broad context of its assessment, but a detailed commentary was judged to be beyond the scope of the present study. The committee's assessment of NHTSA's consumer information on rollover is presented in Chapter 4. In the absence of empirical data on consumers' use of this information, the committee assessed the practicality and usefulness of the rollover resistance ratings by extrapolating from research on a range of consumer products, using its judgment, and evaluating the process used by NHTSA to develop the ratings. The committee's assessment also draws on the findings and recommendations of the Committee for the Study of Consumer Automotive Safety'600 |