A review of applications of steam in evaluating transportation alternatives

A review of applications of steam in evaluating transportation alternatives

DeCorla-Souza, Patrick

By Patrick DeCorla-Souza, Community Planner, Federal Highway Administration (FHWA)

U.S. federal legislation emphasizes assessment of multimodal alternatives and demand-management strategies. This emphasis has increased the need for planners to provide good comparative information to decision makers. To assist in providing such comparative information, FHWA developed the Surface Transportation Efficiency Analysis Model (STEAM). The software was released in January 1998 and is being used in various metropolitan planning applications in the United States and abroad.

STEAM accepts input directly from the four-step, traveldemand modeling process or from off-model software such as FHWA’s travel demand management (TDM) software. It postprocesses traffic-assignment outputs from conventional fourstep planning models to get more accurate highway travel speeds, especially under congested conditions. It performs risk analysis to clearly describe the level of uncertainty in the results of the analysis. The software allows development of monetized impact estimates for a wide range of transportation investments and policies, including major capital projects, pricing and TDM. Impact measures are monetized to the extent feasible, but quantitative estimates of natural resource usage (i.e., energy consumption) and environmental impact (e.g., emissions) also are provided. Net monetary benefits (or costs) of alternatives are output. STEAM is highly flexible in terms of the transportation modes, trip purposes and time periods analyzed. STEAM is used in system planning and in corridor planning studies by state departments of transportation, metropolitan planning organizations, transit agencies and/or their consultants.

Contact Patrick DeCorla-Souza, FHWA, HEP-20, 400 Seventh St., S.W, Washington, D.C. 20590 USA; 202/366-4076; fax: 202/366-3713; partick.decorla-souza@fhwa.dot.gov.

Copyright Institute of Transportation Engineers Feb 1999

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