Planning, evaluating, selecting, and financing highway investments require an understanding of the fundamental empirical relationships between the physical and service characteristics of roadways and associated user costs. Integral to estimating highway needs are accurate measures of the economic costs associated with vehicle operation, accidents, emissions, and travel time--each expressed as a function of highway conditions. NCHRP Project 2-17(1) concluded that very few transportation agencies use user-cost or benefit-cost analysis in the appraisal of capital projects. Policy makers and planners need innovative methods to facilitate decision making, including methods that provide a means of understanding the quantitative significance of uncertainty and risk. NCHRP Project 2-18 systematically analyzed the factors involved in user cost analyses, formulated models to relate these cost components to highway and traffic conditions, identified the key data associated with each, and pioneered in the use of uncertainty or risk analysis in conjunction with user cost estimation. The need exists to document the data and models developed in the project and to translate the methodology into a tool which can be used to address questions related to the strategic selection of projects.
The objectives of this research were to develop an innovative highway user-cost estimation methodology based upon uncertainty analysis and to prepare materials to facilitate the use of this methodology.
These efforts were intended to facilitate highway user cost estimation, lay the groundwork for the development and buy-in of more sophisticated models, and provide a benchmark for future research efforts. To accomplish this objective, the following tasks were accomplished: (1) Formalize a design concept for a strategic user-cost estimation model which would embody the components for relating user costs and benefits in the previous research, use a modular design to allow future integration of revised or additional components, and support agency-wide strategic planning and policy purposes. A simplified form of the model should be available for hand-calculation. (2) Develop an outline for a highway user-cost estimating manual that will describe the application of the new user-cost estimation methodology and the available data. The applications section should describe information needs and methodologies for various types of analyses. The data outline should be structured to indicate acceptable ranges of values and provide guidance to the user on selecting appropriate values. (3) The conceptual design of the methodology and outline of the manual should be described in an interim report. (4) Solicit feedback on a revised version of the outline and conceptual design from potential users of this tool. (5) Develop the highway user-cost estimating manual, including any revisions requested by the panel. (6) Upon approval by the project panel, proceed with the development of the methodology, associated computer models, and documentation. Conduct and document the verification and validation tests of the software to ensure its functionality. (7) Develop a plan for field testing the method and evaluating its usefulness by undertaking case studies in at least three jurisdictions. (8) Prepare a final report which includes the manual, documentation for the software, and provides recommendations for future research.
: Evaluation of the StratBENCOST software and documentation is complete. It was judged to be a potentially useful tool for transportation investment analysis. A decision has been made not to publish the project reports, but to update and enhance them in the continuation effort, Project 2-18(4).
The contractor's final report and the software are available from the NCHRP. The results of this project and of NCHRP Project 2-18(4) will be published in NCHRP Research Results Digest 252,
"Development and Demonstration of StratBENCOST Procedure."