Feb 22 2002
National Academy of Sciences Confirms Sen. Shelby's Concerns with Rating System
WASHINGTON, DC - The National Academy of Sciences has today released their study of the system used by the National Highway Traffic Safety Administration (NHTSA) to assess and rate a vehicle's likelihood to roll over. The study, "An Assessment of the National Highway Traffic Safety Administration's Rating System of Rollover Resistance," confirms many of the concerns raised by Senator Shelby when the system was proposed by NHTSA and considered by Congress.
The study was authorized by Senator Shelby in the Transportation Appropriations bill for Fiscal Year 2001. Senator Shelby requested the study to analyze NHTSA's proposed "five star rating system" based on the static measurements of vehicle track width and center of gravity, or "static stability factor(SSF). Senator Shelby, along with several consumer advocacy organizations voiced concern that the SSF was not as reliable as a crash test, would provide insufficient consumer information, and did not include factors such as driver behavior and environmental conditions.
The National Academy of Sciences today announced the SSF-based system does not take into account driver behavior and environmental conditions nor crash-avoidance technologies within vehicles that offset the propensity for rollover. The study also agreed with Senator Shelby's concern that NHTSA's star ratings are likely to be of limited use in presenting practical information to the public, because of shortcomings in the statistical methodology, the "coarse" rating categories of the system, the insufficient information for useful comparison, and the procedures used to develop and evaluate the star rating system.
The National Academy of Sciences recommended that NHTSA "vigorously pursue" a dynamic rollover testing regime and revise their information to modify SSF with dynamic testing results.
"The National Academy validates what I suspected about the Static Stability Factor calculation -- that it was at best incomplete and at worst a disservice to consumers," said Senator Shelby. I hope the NHTSA will immediately address these deficiencies and pursue actual rollover testing consistent with the National Academy recommendations.
"Consumers deserve accurate, comprehensive and scientifically sound information," added Shelby.
Information regarding the study can be found at: www.nap.edu.