TRAFFIC ASSIGNMENT: BPR TO HCM (PART I)--DENVER'S APPLICATION

One requirement of the Clean Air Act Amendments (CAAA) is to estimate vehicular emissions. Forecasting vehicle emissions is based on projections from the travel demand forecasting model. Consequently, changes in the travel demand model would affect air pollution forecasting. In response to the CAAA, Denver is revising its transportation modeling process, especially in the traffic assignment procedure. Since volume-delay functions are the basis for the traffic assignment algorithm, Denver switched from the Bureau of Public Roads (BPR) volume-delay function to the Highway Capacity Manual's (HCM) volume-delay functions. As a result, a set of mathematical expressions based on the 1985 HCM was developed. Existing BPR-based assignments and the new HCM-based assignments were then evaluated according to three criteria: 1) assignment convergence and equilibrium status, 2) system performance, and 3) impacts on air quality modeling.

• Supplemental Notes:
  • Additional support was provided by the Puget Sound Regional Council and King County, Washington.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001

  Washington State Department of Transportation

  Transportation Building, 310 Maple Park Avenue SE, P.O. Box 47300
  Olympia, WA  United States  98504-7300
• Authors:
  • Feng, L-Y
  • Gion, L C
• Conference:
  • Fifth National Conference on Transportation Planning Methods Applications-Volume I. A Compendium of Papers Based on a Conference Held in Seattle, Washington in April 1995
  • Location: Seattle, Washington
  • Date: 1995-4-17 to 1995-4-21
• Publication Date: 1995-6

Language

• English

Media Info

• Features: Figures; Tables;
• Pagination: 10p

Subject/Index Terms

• TRT Terms: Air quality; Algorithms; Forecasting; Mathematical models; Pollutants; Standards; Traffic assignment; Travel demand; Volume changes
• Identifier Terms: Clean Air Act Amendments; Highway Capacity Manual; U.S. Bureau of Public Roads
• Uncontrolled Terms: Emission standards; Models
• Geographic Terms: Denver (Colorado)
• Subject Areas: Highways; Planning and Forecasting; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 00711577
• Record Type: Publication
• Files: TRIS, TRB, STATEDOT
• Created Date: Sep 24 1995 12:00AM