Developing a Method Selection Tool for Travel Forecasting (2017)

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Final Report Project No. 08-94 1 CHAPTER 1. BACKGROUND 1(A) LEGISLATIVE HISTORY Travel forecasting practitioners must now answer complex planning and policy questions using travel forecasting models originally developed with a narrower objective (McNally, 2000). Travel forecasting models were originally used to evaluate roadway facility expansion. These models are now used to evaluate pricing, environmental, economic, and growth policies as well as highway, transit, nonmotorized, and freight alternatives. Evaluations also include an expanding set of performance metrics to compare the benefits and costs of the alternatives. Examples of new performance metrics include the effects on the built environment, public health, and distribution of effects across different socioeconomic groups. Federal regulations and funding requirements are the primary drivers of travel forecasting model changes (Johnston, 2004). These regulations have led to travel model improvements in managing travel demand, connecting modes, reducing emissions, and evaluating equity. More recently, reductions in public funding have led to travel model improvements in evaluating economic development, pricing strategies, and comparing economic effects. Figure 1 identifies the travel forecasting model requirements derived from these federal regulations. Decision-makers for transportation planning organizations rely on both quantitative and qualitative evaluations of projects and programs to inform investment, operations, and management decisions. The federal regulations direct the necessary elements of this evaluation and provide funding for solutions. As early as 1964, equity analysis and integrated modeling were the preferred methods to address the regulatory requirements of the Civil Rights Act, but those early methods did not provide theoretically sound results. Travel forecasting practitioners now use multiple tools—with the advent of improved forecasting methods—in concert with increased regulation. These tools include more-focused, less-complex modeling systems that can address specific questions, and more-complex modeling systems that can address additional policy implications. Planning agencies also have local requirements that will affect the types of modeling systems for individual programs or plans. Information on tradeoffs for different methods and features—in terms of costs and benefits—will assist planning agencies in making strategic decisions when developing or updating their current methods and tools. The new surface transportation authorization act, titled Moving Ahead for Progress in the 21st Century (MAP-21, P.L. 112-141), establishes mandated performance-based measures for national goals for safety, infrastructure condition, congestion reduction, system reliability, freight mobility and economic vitality, environmental sustainability, and project-delay reduction. The last step in the performance-based planning process is establishing targets by which progress is measured. States will have one year to set a target for each of the national goals, and must coordinate with metropolitan planning organizations (MPOs) in doing so. States may set different targets for urban and rural areas.

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Final Report Project No. 08-94 3 1(B) TRANSPORTATION PLANNING PROCESS Transportation planning plays a significant role as state, regional, and local agencies develop visions for their futures. Transportation planning includes a comprehensive consideration of possible strategies, an evaluation process that often includes diverse opinions, collaborative participation by all relevant transportation-related agencies and organizations, and public outreach and involvement. Transportation planning uses a process to promote involvement by all users of the transportation system, including the business community, community groups, environmental organizations, freight operators, and travelers through a public participation process conducted by the MPO, state department of transportation (DOT), or transit operator. Transportation planning includes the following:  Describing existing conditions.  Forecasting future population and employment growth, including assessing projected land uses in the region and identifying major growth corridors.  Identifying current and projected future transportation problems and needs and analyzing, through detailed planning studies, various transportation improvement strategies to address those needs.  Developing long-range plans and short-range programs of alternative capital improvement and operational strategies for moving people and goods.  Estimating the effect of recommended future improvements to the transportation system on environmental features, including air quality.  Developing a financial plan for securing sufficient revenues to cover the costs of implementing strategies. Quantitative tools and methods are used by state DOTs, MPOs, and local agencies to support many different elements of the transportation planning process. Transportation planning can be further generalized to identify where forecasting and analysis is performed as part of the larger process to aid decision-makers and stakeholders in helping to achieve their stated goals and objectives. This research focuses on the quantitative tools and methods used to perform travel forecasting and analysis, which provides information for evaluation. 1(C) PROJECT OBJECTIVES This research developed guidance on the process to select methods for long-range planning travel forecasting tools. The guidance assists in identifying model improvements appropriate for the desired level of transportation analysis by weighing the costs and benefits to make informed choices with constrained resources. This guidance also assists transportation planners and modelers in communicating the strengths and limitations of the model improvements to decision- makers. This research addressed broad model updates required by a transportation plan or program and corridor- or area-specific model improvements required by a specific transportation project. As a result, the guidance helps transportation planners and modelers evaluate the requirements of a plan, program, or project and the desired performance metrics and cost and schedule constraints to support a transportation plan or program.

Final Report Project No. 08-94 4 The guidance focuses on the primary travel forecasting methods in use today. The travel forecasting methods included passenger travel forecasting, commercial vehicle and freight travel forecasting, and assignment and simulation methods. (Other methods are also included in the guidance that fall outside these three primary categories of travel forecasting methods.) The current version of the guidance does not include pre- and postprocessing methods used to develop inputs for travel forecasting methods and 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; project prioritization; and visualization methods. The guidance developed for this project was designed to allow expansion for new methods in future versions to include these—or other—future methods. The guidance was developed in two forms. First, there is a decision-support system implemented as an online software tool that produces recommendations for travel forecasting methods based on a series of user inputs. Second, there is a reference guide that can be accessed via the software tool, called Travel Forecasting Guide (“TFGuide”), or via its User Guide, NCHRP Research Report 852: Method Selection for Travel Forecasting. The guidance recommends methods that are useful to address a planning program or project while providing information on the scope, schedule, and budget needed to implement these methods. These methods require additional resources in staff training, software, hardware, or data. These additional resources are reported in the guidance 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 guidance identifies resources or data items needed to support a new method, but users are responsible for researching the details needed to develop a scope, schedule, or budget to obtain these resources. As stated, the guidance and software developed here were designed to allow expansion for new methods, which could include methods for data collection, analysis, and use. This guidance 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 needs. This feature is optional—agencies can choose to identify current methods and resources, and these 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 feature can be left blank and the recommendations, cost, and schedule for the enhancements will include all recommendations. The decision-support system underlying this guidance does not include an evaluation of the quality or capabilities within an agency’s current methods. As a result, the guidance is not designed to assess readiness for an agency’s current methods to support the recommended enhancements. The focus of the guidance was on identifying and informing users on potential travel forecasting enhancements that an agency may not be aware of to support transportation planning analysis.

Final Report Project No. 08-94 5 1(D) AUDIENCE The three potential audiences for the products of this research are 1) travel forecasting practitioners; 2) transportation planners; and 3) transportation decision-makers. The goals of these three audiences align, but the language used to inform each audience varies. The guidance provides information accessible to each audience: technical information, for travel forecasters; information connecting the planning question to the methods, for planners; and information on how to communicate the costs and benefits of each method to decision-makers. The guidance relies on relationships between the capabilities of various methods with the requirements and constraints of a planning study. The guidance provides high-level technical details for each method and references for further details to inform travel forecasting practitioners, transportation planners, and transportation decision-makers. The guidance has not been designed to serve as a technical “how-to” guide for practitioners; instead, the guidance provides details on the scope, schedule, and budget required to implement each new method. Users are expected to be both technical and nontechnical staff at state, regional, transit, and toll agencies. It is expected that practitioners who are new to travel forecasting can learn from the guidance and that practitioners 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 TFGuide. 1(E) DELIVERABLES The research includes three primary products:  The first product is an online method selection software tool—TFGuide—that includes the ability to trade off costs and benefits for individual methods and features. This software is intended to be used by practitioners. TFGuide includes a built-in reference guide.  The second product is NCHRP Research Report 852: Method Selection for Travel Forecasting: User Guide with 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. The document is intended to be used by practitioners in conjunction with TFGuide.  The third product is this contractor’s final report for the research study, NCHRP Web- Only Document 234: Developing a Method Selection Tool for Travel Forecasting, 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 the expert panel and others interested in the background research. This research has identified potential methods to answer planning questions. These questions pertain to the environmental, transportation, quality-of-life, and equity considerations. Practitioners want to keep up with research on new methods and policy and planning questions that cannot be answered with current methods, but often do not have the time required to keep up with new research. A primary goal of this research is to provide a means for practitioners to identify new methods that directly apply to their challenges. Selecting a travel forecasting

Final Report Project No. 08-94 6 method can affect schedules, budgets, and the quality of information used in decision-making for transportation investments. This research will support travel forecasting practitioners in identifying the right-size tool. 1(F) CONTENT OF THIS REPORT In addition to the front matter and back matter, this Web-Only Document comprises four chapters:  Chapter 1 includes a discussion of the legislative history for travel forecasting model requirements, an overview of how travel forecasting fits within the transportation planning process, the project objectives, and the intended audience for the guidance and deliverables.  Chapter 2 provides the details of the research approach, including an overview of the state-of-the-practice review and the software design for the guidance. The software design includes the method selection components, the online software tool design, and the final user functionality for TFGuide.  Chapter 3 references the parallel report on the TFGuide software tool and includes additional information on the administrative functionality in TFGuide and documentation about the pilot tests conducted using the draft version of the software.  Chapter 4 includes a summary of the project and recommendations for further enhancements that were identified during the research process. As noted in the prior section on deliverables and in Chapter 3, NCHRP Research Report 852: Method Selection for Travel Forecasting: User Guide contains a user guide and reference guides (included as appendices) for TFGuide. This Web-Only Document focuses on the work conducted in the project, while the User Guide focuses on the use of the online tool.