Method Selection for Travel Forecasting (2017)

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1 Project Objectives This research project developed recommendations for selecting methods for long-range travel- forecasting tools while considering individual planning needs. The products developed assist in identifying model improvements appropriate for the desired level of transportation analysis by weighing costs and benefits in order to enable informed choices to be made with constrained resources. This research provides information to help forecasters, planners, and decision makers better understand the forecasting methods that may be useful for their transportation plan- ning needs. The research sought to address broad model updates required by a transportation plan or program and corridor- or area-specific model improvements required by a specific transporta- tion project. As a result, the project team developed a decision-support system to evaluate the requirements of a plan, program, or project; the desired performance metrics; and cost and schedule constraints to support a transportation plan or program. The research focused on the primary travel-forecasting methods in use at the time of this project: passenger travel forecasting, commercial vehicle and freight travel forecasting, and assignment and simulation methods. In addition, other methods that fall outside these three primary categories of travel-forecasting methods were included in the research. The current version of the decision-support system does not include pre- and postprocessing methods used to develop inputs for travel-forecasting methods and to develop metrics from travel model outputs, such as economic, land use, and demographic methods; person, household, and firm characteristics methods; impacts and performance metric methods; and project prioritization and visualization methods. The software and user guide developed for this project were designed to allow expansion so that future versions can include these—or other—future methods. The software and user guide recommend methods that are useful to address a planning pro- gram or project while also providing information on the scope, schedule, and budget needed to implement these methods. The additional resources in staff training, software, hardware, and data needed by these methods are reported in the user guide at a high level (as desired for implementing a method), but an assessment of the quantity and quality of these resources and data was outside the scope of this research. This user guide has been developed to identify resources or data items needed to support a new method, but the user is responsible for researching the details needed to develop a scope, schedule, or budget to obtain these resources. As stated previously, the software and user guide are designed to allow expansion for new methods, which could include methods for data collection, analysis, and use. This software was also designed to account for an agency’s existing methods and resources so that recommendations can focus on future enhancements to support transportation planning Introduction C H A P T E R 1

2 Method Selection for Travel Forecasting: User Guide needs. This feature is optional: Agencies can choose to identify current methods and resources, which will be excluded from recommendations for new methods and the cost and time to develop these methods. If agencies do not have any current methods or resources, or if agencies want to evaluate all recommendations (including current methods and resources), then this option can be left blank and the recommendations, cost, and schedule for the enhancements will include all recommendations. The decision-support system underlying the software does not include an evaluation of the quality or capabilities within an agency’s current methods. As a result, the software is not designed to assess readiness for an agency’s current methods to support the recommended enhancements. The software was also not designed to assess the calibration, validation, or quality of the outputs of any individual method. The software identifies, and informs users of, potential travel-forecasting enhancements—that an agency may not be aware of—to support transportation planning analysis. Audience The three potential audiences for the software and user guide are (1) travel-forecasting practi- tioners, (2) transportation planners, and (3) transportation decision makers. The goals of these three audiences align, but the language used to inform each audience is different. The software provides information accessible to each audience: (1) technical information for travel forecasters, (2) information connecting the planning question to the methods for planners, and (3) informa- tion on how to communicate the costs and benefits of the method to decision makers. The software relies on relationships between the capabilities of various methods with the require- ments and constraints of a planning study. It provides high-level technical details for each method and references for further details to inform travel-forecasting practitioners, transportation plan- ners, and transportation decision makers. The software is not designed to be a complete technical “how-to” guide for practitioners; instead, the software provides high-level details of the scope, schedule, and budget required to implement a new method. Users are expected to be both technical and nontechnical staff at state, regional, transit, and toll agencies. Practitioners who are new to travel forecasting can learn from the software, and prac- titioners who have a background in travel forecasting can advance their understanding of new methods. Users with an advanced travel-forecasting background may also discover new methods by using this tool. Products The research provided three primary products: • An online method selection software tool—TFGuide—that contains the information from the Reference Guide and can trade off costs and benefits for individual methods and features. This software is intended to be used by practitioners. • This user guide, which contains instructions on how to use the software tool and reference guides (included as appendices) for the methods, requirements, and performance metrics that are included in the travel-forecasting guidance. This user guide is intended to be used by practitioners in conjunction with the software, TFGuide. • NCHRP Web-Only Document 234: Developing a Method Selection Tool for Travel Forecasting, the contractor’s final report for the research project, which includes the background research for the guidance, the pilot tests conducted, the administrative functionality in the software tool, and potential future enhancements. This document is intended for use by those interested in the background research.

Introduction 3 This guidance identifies potential methods that are appropriate to answer planning questions pertaining to the economy, environment, transportation, safety and health, and equity. Practi- tioners are encouraged to keep up with new research, new methods, and policy and planning questions that cannot be answered with current methods; however, it is understood that time and budget constraints often preclude robust continuing education initiatives for agencies and their employees. Selecting a travel-forecasting method can affect schedules, budgets, and the quality of information used in decision making for transportation investments. This research supports travel-forecasting practitioners in identifying the right-size tool. Report Contents This research report contains five chapters and five appendices: • Chapter 1 introduces the objectives for the research and the audience and products resulting from the research. • Chapters 2 through 5 are the user guide. These chapters provide instructions on how to use the method selection software tool (TFGuide). This includes information on how to manage sce- narios and use the interactive reference guide included in the software. TFGuide is an online software tool where users can develop and maintain their own scenarios. • Appendices A through E are the reference guides. These appendices replicate the reference guide in the software for each data element in the software. These appendices provide a description of each data element and the relationships that each data element has with the programs, methods, requirements, and resources in the system.