An Assessment of the National Highway Traffic Safety Administration's Rating System for Rollover Resistance Special Report 265 (2002) / Chapter Skim
Currently Skimming:
Executive Summary
Executive Summary
Pages 1-8
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 1... ...
Public Law 106-346 required the U.S. Department of Transportation to fund a study "on whether the static stability factor is a scientifically valid measurement that presents practical, useful information to the public, including a comparison of the static stability factor test versus a test with rollover metrics based on dynamic driving conditions that may induce rollover events." Particular emphasis was to be placed on the potential role of consumer information on vehicle characteristics, in particular SSF, in achieving a reduction in the rollover crash rate and in related deaths and injuries.
|
From page 2... ...
The important question addressed by this report is the extent to which the vehicle -- and in particular its SSF value -- affects the risk of rollover for different drivers and driving environments. As noted, in accordance with the requirements of Public Law 106-346, this study focuses on the potential for reducing the rollover crash rate, as well as resulting deaths and injuries, by providing consumer information related to vehicle characteristics, specifically SSF.
|
From page 3... ...
The agency reviewed crash frequencies and rollover rates, and used data from six states, selected as representative of national trends, for regression analyses using an exponential statistical model.6 At the request of the committee, NHTSA conducted additional analyses of these crash data using a logit statistical model. The agency computed separate rollover curves and associated confidence bands for different crash scenarios.7 These curves indicate that an increase in SSF reduces the probability of rollover in the event of a single-vehicle crash, although this trend is less pronounced for lower-risk scenarios.
|
From page 4... ...
If the vehicle's SSF indicates that -- according to the average rollover curve -- it has a rollover probability of greater than 40 percent in the event of a single-vehicle crash, it is assigned a one-star rollover resistance rating. Rollover curves generated from crash data represent an average over many different vehicle makes and models.
|
From page 5... ...
SUMMARY FINDINGS The committee has synthesized its findings in the areas of vehicle dynamics, statistics and data analysis, and consumer information into two summary findings that respond to the congressional mandate for this study. Summary Finding 1 SSF captures important vehicle characteristics related to rollover propensity and is strongly correlated with the outcome of actual crashes (rollover versus no rollover)
|
From page 6... ...
Despite the absence of technical barriers to providing more comprehensive consumer information on rollover, the protracted history of NHTSA's rulemaking initiatives on rollover suggests that the agency may encounter difficulties in obtaining support for its actions from all the major stakeholders. Furthermore, vehicle manufacturers, consumer groups, and others involved in vehicle testing are likely to incur additional costs when NHTSA introduces dynamic testing related to rollover.
|
From page 7... ...
Recommendation 2 In the longer term, NHTSA should develop revised consumer information on rollover that incorporates the results of one or more dynamic tests on transient vehicle behavior to complement the information from static measures, such as SSF. Recommendation 3 NHTSA should investigate alternative options for communicating information to the public on SSF and its relationship to rollover.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.