Highway Safety:

Reliability and Validity of DOT Crash Tests

PEMD-95-5: Published: May 8, 1995. Publicly Released: May 8, 1995.

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Pursuant to a congressional request, GAO reviewed the National Highway Traffic Safety Administration's (NHTSA) crash test programs, focusing on whether they provide valid and reliable indicators of occupant safety in real world crashes.

GAO found that: (1) the probability of sustaining a serious injury has declined since the inception of NHTSA test programs; (2) cars marketed in the United States have become more crashworthy; (3) the consistency of New Car Assessment Program (NCAP) test results is questionable and its unreliable data may lead to misinformed purchasing decisions; (4) NCAP ability to predict a vehicle occupant's protection in real world crashes is limited, since NCAP results can only be applied to frontal collisions; and (5) there is a statistically significant relationship between fatality rates and NCAP-predicted injuries, however, these high fatality rates are associated with the poorest NCAP performers.

Recommendations for Executive Action

  1. Status: Closed - Implemented

    Comments: NHTSA has reviewed and reported on the reliability of NCAP test results and concluded that it is acceptable. NHTSA has also adopted a simpler and clearer presentation of test results for the general public. However, this presentation does not clearly communicate the range of uncertainty that is associated with a score from a single test. GAO is unaware of any plans to update the 1984 repeatability study.

    Recommendation: The Administrator, NHTSA, should update information on NCAP reliability and make this information more available, in clear language, to the general public. Such an effort would require an update of the repeatability study that the agency conducted in 1984 and could result not only in a better understanding of the reliability of crash tests for predicting injury risk, but also in discovering ways in which NHTSA can limit the error that derives from sources under its control.

    Agency Affected: Department of Transportation: Federal Highway Traffic Safety Administration

  2. Status: Closed - Implemented

    Comments: The agency continues research activities to explore computer modeling to assess its potential for supplementing crash testing. The agency continues to solicit test results from manufacturers on all vehicles that are tested in NCAP. These activities will be conducted on a continuous basis.

    Recommendation: NHTSA should explore the feasibility of alternative means of testing the crashworthiness of new vehicles. Computer simulations may provide one such alternative. It may be possible to better assess the safety potential of a vehicle through computer-based modeling as this allows more trials, more quickly, and modeling is capable of simulating impacts at all points of a vehicle. In addition, this rapidly emerging technology has the added capability of providing immediate insights into redesigning vehicles in which the crashworthiness may not yet be optimal.

    Agency Affected: Department of Transportation: Federal Highway Traffic Safety Administration


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