title: Undercounting of large trucks in federal and state crash databases: Extent of problem and how to improve accuracy of truck classifications.
abstract: OBJECTIVE
  Prior research suggested that single-unit trucks are undercounted when using vehicle body codes in the Fatality Analysis Reporting System (FARS). This study explored the extent of the misclassification and undercounting problem for crashes in FARS and state crash databases.
  
  
  METHODS
  Truck misclassifications for fatal crashes were explored by comparing the Trucks Involved in Fatal Accidents (TIFA) database with FARS. TIFA used vehicle identification numbers (VINs) and survey information to classify large trucks. This study used VINs to improve the accuracy of large truck classifications in state crash databases from 5 states (Delaware, Maryland, Minnesota, Nebraska, and Utah).
  
  
  RESULTS
  The vehicle body type codes resulted in a 19% undercount of single-unit trucks in FARS and a 23% undercount of single-unit trucks in state databases. Tractor-trailers were misclassified less often. Misclassifications occurred most frequently among single-unit trucks in the weight classes of 10,001-14,000 pounds.
  
  
  CONCLUSIONS
  The amount of misclassification of large trucks is large enough to potentially affect federal and state decisions on traffic safety. Using information from VINs results in more complete and accurate counts of large trucks involved in crashes. The National Transportation Safety Board recommended actions to improve federal and state crash data.
authors.affiliation: a National Transportation Safety Board , Washington, D.C.
authors.forename: Ivan
authors.initials: I
authors.lastname: Cheung
authors.affiliation: a National Transportation Safety Board , Washington, D.C.|b Department of Epidemiology and Public Health , University of Maryland School of Medicine , Baltimore , Maryland.
authors.forename: Elisa R
authors.initials: ER
authors.lastname: Braver
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D016208:Databases, Factual / Q000592:standards*; D006801:Humans; D018986:Motor Vehicles / Q000706:statistics & numerical data*; D014481:United States
keywords: database linkage; fatality; injury; large trucks; misclassification; motor vehicle crashes