* The Urban Institute was the original research agency under Project 8-31.

The objectives of this research are to evaluate the scope and severity of current and future capacity problems and constraints on transportation corridors and to recommend strategies to ensure the long-term availability of multimodal corridor capacity.

To meet the objectives, a two-phased project was conducted. The purposes and the tasks associated with each phase are described as follows:

Phase I had two purposes: First was to develop an analytical methodology, including a manual, for performing multimodal corridor capacity analysis. A second purpose was to evaluate completed and ongoing studies and data on current and future multimodal corridor capacity. Phase I required the following tasks: (1) Review the literature and identify and develop definitions of terms appropriate for the key issues in this study. The terms shall include but not be limited to multimodal corridor, capacity, congestion, and long term. (2) Identify, evaluate, and summarize completed and ongoing studies of corridor problems, capacity preservation and expansion strategies, methods of corridor administration, and shipper, carrier, and traveler responses to congestion. (3) Develop a multimodal corridor capacity analysis manual that will serve as the analytical framework for the corridor analyses to be conducted as part of this research project. Based on the findings of Tasks 1 and 2, develop a typology of transportation corridors including, but not limited to, severity of traffic problems, facility expansion constraints, and feasible multimodal transportation alternatives. Using the analytical framework of the corridor capacity analysis manual and the typology, develop a detailed work plan for the research to be conducted in Phase II. The plan should include a proposed methodology for quantifying congestion and total corridor capacity both for the present and for the long-term future. As a minimum, the plan should provide information to produce the following: (a) identification of the constraints on current and future expansion of transportation corridor capacity, (b) identification of various responses by transportation users and providers to corridor congestion, (c) quantification of the impact of those responses by transportation users and providers on corridor congestion, (d) characterization of the competition for corridor capacity between various users and providers, and (e) a summary of the potential contributions of nontraditional solutions to corridor congestion. (4) Prepare a Phase I interim report documenting the findings of Tasks 1 through 3 and providing a detailed work plan for Phase II. Meet with the NCHRP project panel to present the interim report. Research on the remaining tasks shall not be initiated until the interim report has been approved by the NCHRP project panel.

Phase II's purpose was to characterize the scope and severity of current and future capacity problems and the constraints on expansion in multimodal corridors and to recommend strategies for preserving long-term capacity. The following tasks were required: (5) Execute the approved work plan for Phase II. (6) Analyze the results to (a) develop the best possible estimate of the number and location of multimodal corridors nationwide where capacity problems exist or are expected soon and (b) formulate recommendations for strategies necessary to ensure the long-term availability of multimodal corridor capacity. (7) Prepare and submit a final report documenting the entire research effort.

Status: The project has been completed.

Report Availability: The final report has been published as NCHRP Report 399,"Mulitmodal Corridor Capacity Analysis Manual."