LETTER REPORT - COMMITTEE TO REVIEW FEDERAL ESTIMATES OF THE RELATIONSHIP OF VEHICLE WEIGHT TO FATALITY AND INJURY RISK

At the request of the National Highway Traffic Safety Administration (NHTSA), the National Research Council, acting through the Transportation Research Board (TRB), convened a committee to review recent NHTSA staff estimates of the relationship of vehicle weight to highway fatality and injury risk. The review was requested because the statistical methods employed to estimate the effects are complex, and the results of the analyses have proved controversial. This letter report summarizes the committee's unanimous findings and conclusions. Concluding remarks of the letter report are as follows: "The committee applauds the efforts of the NHTSA researchers to tackle the complex and challenging issue of the relation between vehicle weight and safety. The data sets maintained by NHTSA are a crucial part of any such analyses. Nonetheless, the committee finds itself unable to endorse the quantitative conclusions in the reports about projected highway fatalities and injuries because of the large uncertainties associated with the results--uncertainties related both to the estimates and to the choice of the analytical model used to make the estimates. Plausible arguments exist that the total predicted fatalities and injuries could be substantially less, or possibly greater, than those predicted in the report. Moreover, possible model misspecification increases the range of uncertainty around the estimates. Although confidence intervals could be estimated and sensitivity analyses conducted to provide a better handle on the robustness of the results, the complexity of the procedures used in the analysis, the ad hoc adjustments to overcome data limitations, and model-related uncertainties are likely to preclude a precise quantitative assessment of the range of uncertainty. The committee believes that it is important, however, for the NHTSA analysts to provide a sense of the range of uncertainty, using qualitative judgments where necessary, so that policy makers and researchers can properly interpret the results."

  • Corporate Authors:

    Transportation Research Board

    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Authors:
    • North, D W
    • Humphrey, N
  • Publication Date: 1996-6-12

Language

  • English

Media Info

  • Features: Appendices; References; Tables;
  • Pagination: 37 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00723787
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jul 9 1996 12:00AM