ISSUES IN TRUCK SIZES AND WEIGHTS--TRUCKING/RAIL TRAFFIC DIVERSION MODELS: THE STATE OF THE ART

An important issue to be examined by policymakers in the near future is whether the legal use of larger capacity trucks will cause any significant reallocation of traffic among competing modes. Very often a lower cost per unit of freight carried can be realized by the use of larger freight carrying vehicles. In the case of truck versus rail competition, some have argued that lower truck rates relative to rail will follow resulting in less rail traffic. This study examines the truck/rail diversion issue by identifying and analyzing numerous mode choice models which have been developed over the past few years. The intention of such models is to determine how freight is likely to be shared by these two modes of transport. The quantitative methods in these mode choice models are criticized for having limited application. Essentially, these apparently sophisticated approaches all suffer the following problems: Problems of determination and inclusion of all relevant variables especially behavioral variables. Lack of necessary input data. Applicable only to the shortrun, due to the model's inherent assumption that technology remains constant. Focus on mode split instead of mode choice, i.e. the freight is allocated as if only two modal choices existed. In sum, these models are underspecified, or applicable to only a few commodities, or both. Furthermore, it seems unlikely that in the near future more complete and accurate models can be expected. The necessary data bases either do not now exist or they are incomplete. In conclusion, the present theoretical mode split models cannot be expected to accurately assess potential diversion. Other approaches are needed. At least in the near term, a less sophisticated, common-sense approach appears more useful. Furthermore, a pragmatic approach could incorporate knowledge of the important operations aspects of both motor and rail transport. (Author)

• Corporate Authors:

  American Trucking Associations

  Research and Economics Division, 1616 P Street, NW
  Washington, DC  United States  20036
• Authors:
  • Serafin, B L
• Publication Date: 1981

Media Info

• Pagination: 44 p.

Subject/Index Terms

• TRT Terms: Accuracy; Highway departments; Laws; Modal diversion; Railroad transportation; Size; Size and weight regulations; State of the art studies; Traffic simulation; Trucks; Trucks by weight; Weight
• Uncontrolled Terms: Increase
• Old TRIS Terms: Traffic departments
• Subject Areas: Highways; Law; Motor Carriers; Planning and Forecasting; Railroads; I10: Economics and Administration;

Filing Info

• Accession Number: 00335412
• Record Type: Publication
• Report/Paper Numbers: TSW-81-11 Tech Rpt.
• Files: TRIS
• Created Date: Jan 29 1982 12:00AM