In each annual publication of "Highway Statistics", FHWA estimates overall travel by broad type of vehicle and type of highway, in the VM-1 table, based on estimates of travel provided by each of the states. These published vehicle miles of travel (VMT) estimates provide control totals for policy and research studies throughout U.S. Department of Transportation (DOT) and by outside the department. Several sources of systematic bias, which together create a tendency to overcount combination vehicles, have been reported and analyzed in a series of studies. In addition, FHWA's inclusion of vehicles towing light trailers along with other combination vehicles produces some misunderstanding and misapplication of data. If light vehicles were excluded from FHWA's combination truck VMT estimates, the published numbers would be closer to VMT estimates from other sources, notably those of the Truck Inventory and Use Survey (TIUS). If FHWA further compensated for the temporal distribution bias that appears to be prevalent in state classification studies, its published numbers would be very close to TIUS estimates of combination truck VMT. This paper presents several recommendations that FHWA may wish to consider in order to improve its estimates of truck VMT, especially for combination vehicles.


  • English

Media Info

  • Features: References; Tables;
  • Pagination: p. 42-46
  • Monograph Title: Issues in marine, intermodal, and motor carrier transportation
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00715633
  • Record Type: Publication
  • ISBN: 0309062047
  • Report/Paper Numbers: HS-042 023
  • Files: TRIS, TRB, ATRI
  • Created Date: Jan 23 1996 12:00AM