Transportation policy and systems in the United States have developed along modal lines with different patterns of ownership. For example, public agencies plan and maintain the highway infrastructure, and private firms build, operate, and maintain rail lines. While there have been some variations on this pattern with the construction of private toll roads and the investment of public funds in rail planning and rehabilitation, public planning and investment decisions are usually made independently by mode. Modal-oriented planning and investment have been shown to be economically inefficient and to generate fewer social benefits than might be achieved under a multimodal approach. For example, research has indicated that abandoning rail lines with the subsequent diversion of traffic from rail to truck can significantly increase highway infrastructure maintenance costs. Thus, the investment of public funds in rail branch lines not only generates shipper benefits but also reduces future highway and bridge costs. There is widespread interest in tools to conduct benefit-cost analysis and economic assessments of alternative transportation improvements since ISTEA. NCHRP Project 20-29, "Development of a Multimodal Framework for Freight Transportation Investments: Consideration of Rail and Highway Trade-Offs," completed research that (1) synthesized good economic principles and practices into a framework for multimodal transportation investment, (2) evaluated various examples of transportation investment trade-offs (focusing on rail-highway trade-offs), and (3) developed a framework for better decision making for transportation investments. Further research is needed to (1) develop tools for the effective application of the framework in multimodal investment analysis, (2) demonstrate the viability and applicability of the framework, (3) identify obstacles to their implementation, and (4) develop strategies for implementing improved practices.
The objectives of this project were to (1) expand and adapt the framework developed in NCHRP Project 20-29 for multimodal, multicriteria transportation investment analysis for both freight and passenger transportation, (2) develop a generic software package to facilitate such analysis, and (3) prepare user-oriented materials to facilitate the use of the methodology.
To accomplish the objectives, the following tasks were accomplished: (1) Review the literature and recent research for new procedures and data applicable to analyzing multimodal transportation investments. (2) Assess the data required to support an expanded version of the transportation investment analysis framework. Document the sources of data, the degree of applicability, any limitations of the data, and other relevant factors. Outline procedures for updating previously compiled support data to the current analysis year, and propose default values where appropriate. (3) Develop an initial version of a convenient, easily distributed software tool with broad applicability in transportation investment analysis in accordance with the plan outlined in Task 2. Prepare documentation for this software that includes data structures, application procedures, process flow diagrams, and output descriptions sufficient to permit outside review of the software. (4) Prepare an interim report documenting the efforts for review and comment by the project panel. (5) Develop a revised version of the software based on the recommendations made by the panel at the interim meeting. Compile additional data as may be required to facilitate the use of the software or to support the incorporation of new capabilities. (6) Conduct appropriate validation and verification tests to ensure that the software performs calculations correctly, default data are adequate, and the results compare favorably with those generated by other means. Outline a plan for the implementation of this tool in transportation agencies. (7) Prepare a user's manual that includes a brief, applications-oriented primer on multimodal, multicriteria transportation investment analysis. (8) Prepare a final report that documents this research effort and includes the user's manual and documentation for the software.
: This project has been completed.
The contractor's draft final report is available through the NCHRP. The software (TransDec) and user's manual may be obtained from the McTrans Center for Microcomputers in Transportation. The results of this project and the capabilities of TransDec are summarized in NCHRP Research Results Digest 258