Method Selection for Travel Forecasting (2017)

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2017 N A T I O N A L C O O P E R A T I V E H I G H W A Y R E S E A R C H P R O G R A M NCHRP RESEARCH REPORT 852 Method Selection for Travel Forecasting User Guide Maren Outwater Kevin Hathaway RSG White River Junction, VT i n p a r t n e r s h i p w i t h Kittelson & Associates, Inc. Oakland, CA Oregon Systems Analytics LLC Salem, OR Keith Lawton Consulting, Inc. Portland, OR Subscriber Categories Highways  •  Planning and Forecasting  •  Public Transportation Research sponsored by the American Association of State Highway and Transportation Officials in cooperation with the Federal Highway Administration

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C O O P E R A T I V E R E S E A R C H P R O G R A M S AUTHOR ACKNOWLEDGMENTS The research report herein was performed under NCHRP Project 08-94 by RSG, in partnership with Kittelson & Associates, Inc., Oregon Systems Analytics LLC, and Keith Lawton Consulting, Inc. Maren Outwater, PE, from RSG was the project’s principal investigator. John Lawlor and Jeff Doyle from RSG were the principal software engineers who developed the software tool (TFGuide) for this project. Kevin Hathaway was responsible for the software design, graphical user interface, and this user guide. Throughout the project, Richard Dowling, PhD, TE, PE, and David Reinke, from Kittelson & Asso- ciates, Inc., and Vince Bernardin, PhD, and Joel Freedman, from RSG, provided expert technical advice on travel-forecasting methods and the relationships between these methods. Keith Lawton and Brian Gregor, from Oregon Systems Analytics LLC, provided useful reviews of the conceptual design and initial draft of TFGuide. Kaveh Shabani, from RSG, and Brian Grady (now with Picaboo Corporation) conducted the state-of-the-practice review. The authors are grateful to the pilot test agencies that provided useful feedback on the draft software tool: Gina Schmidt and Sanghyeon Ko, PhD, from the Association of Monterey Bay Area Governments (AMBAG); Xuan Wang, PhD, PE, from the Regional Transportation Commission (RTC); Peng Xiao, PE, PTOE, PMP, and Terrell Hughes, PE, from the Virginia Department of Transportation (VDOT); and Julie Dunbar from Dunbar Transportation Consulting (DTC). CRP STAFF FOR NCHRP RESEARCH REPORT 852 Christopher J. Hedges, Director, Cooperative Research Programs Lori L. Sundstrom, Deputy Director, Cooperative Research Programs Lawrence D. Goldstein, Senior Program Officer Anthony P. Avery, Senior Program Assistant Eileen P. Delaney, Director of Publications Natalie Barnes, Senior Editor NCHRP PROJECT 08-94 PANEL Field of Transportation Planning—Area of Forecasting Keith L. Killough, Arizona DOT, Phoenix, AZ (Chair) Todd A. Brauer, Whitehouse Group Inc., Ft. Lauderdale, FL Suzanne Childress, Puget Sound Regional Council, Seattle, WA Greg Giaimo, Ohio DOT, Columbus, OH Konstadinos Goulias, University of California, Santa Barbara, CA Kenneth D. Kaltenbach, The Corradino Group, Inc., Louisville, KY Becky A. Knudson, Oregon DOT, Salem, OR John S. Thomson, Kentucky Transportation Cabinet, Frankfort, KY Ken Cervenka, FTA Liaison Jeremy Raw, FHWA Liaison Jennifer L. Weeks, TRB Liaison

NCHRP Research Report 852: Method Selection for Travel Forecasting presents guidelines for travel-forecasting practitioners to (1) assess the suitability and limitations of their travel- forecasting methods and techniques to address specific policy and planning questions; (2) scope model development or improvements so as to attain the desired policy sensitivity within constraints such as institutional, budget, model development time, and resources; and (3) communicate limitations and any improvements to decision makers. The guide- lines include a software tool, TFGuide, which illustratively and systematically “guides” the practitioner through the selection of methods and techniques based on application needs, resource constraints, available data, and existing model structure. NCHRP Research Report 852 is designed for practitioners at state transportation agencies; metro politan planning organizations (MPOs); transit agencies; and consultants who scope, develop, and apply travel-forecasting models. It is coupled with and supports the method selection software tool, TFGuide. To access the software, use the following URL, username, and password: URL: https://rguide.rsginc.com Username: TFGuide Password: r3c0mm3nd2t10n In addition, NCHRP Web-Only Document 234: Developing a Method Selection Tool for Travel Forecasting, which is available by searching for “NCHRP Web-Only Document 234” on the Transportation Research Board website (www.trb.org), documents the research behind the development of the method selection process and resulting software tool. Travel demand modelers are increasingly being asked to address new and more com- plex policy and planning questions, especially as new and more extensive sources of data have emerged. Although many advances and innovations in travel-forecasting tech- niques have been developed in recent years, selecting and applying these techniques appropriately remains challenging. Recognizing these changes, this research responds to a growing need for developing resources aimed at practitioners at state transportation agencies and metropolitan planning organizations (MPOs) to help them evaluate the capa- bilities and limitations of their existing methods and techniques with respect to specific policy and planning questions and, further, to assist them in scoping model development and improvements. This research builds on and supplements existing literature from the Federal Highway Administration, Federal Transit Administration, and Transportation Research Board and other documentation of available travel-forecasting methods and techniques. F O R E W O R D By Lawrence D. Goldstein Staff Officer Transportation Research Board

Past guidance on methods has historically been relatively narrow and did not effectively connect travel-forecasting techniques to increasingly complex planning activities. In response, this research identifies applicable methods by evaluating agencies’ planning programs, desired performance metrics, requirements, and constraints. Methods are ranked by costs and benefits so users can review the determinants of each method and weight the requirements so that selected methods reflect an agency’s specific priorities. The guide, which recommends application of various travel-forecasting methods individually or as a package (i.e., a model- ing system) to meet agency planning needs, is implemented using the interactive decision- support software, TFGuide. An important attribute of TFGuide is that it permits changes to the underlying requirements to produce an individualized set of methods for consideration. Planning and policy questions addressed by the research cover a broad range of issues: • long-range planning • performance-based planning • safety • project prioritization • traffic impact study • operational analyses • pricing study • air quality and climate change analyses • transit analyses • walk and bike activity forecasting • freight planning • environmental justice analyses • economic impact analyses • emergency management • other planning issues that models are often asked to address Each of the planning and policy issues identified are coupled to a set of “information needs,” such as (a) level of temporal and spatial flows by market segment, (b) volume and speed outputs, (c) mode of travel, (d) travel cost, (e) travel delay, and (f) other relevant performance metrics.

Note: Photographs, figures, and tables in this report may have been converted from color to grayscale for printing. The electronic version of the report (posted on the web at www.trb.org) retains the color versions. 1 Chapter 1  Introduction 1 Project Objectives 2 Audience 2 Products 3 Report Contents 4 Chapter 2  Getting Started 4 Logging In 4 Home Page 5 General Settings 7 Chapter 3  Building a Scenario 7 Step 1: Selecting a Program or Plan 8 Step 2: Specifying Plan or Program Requirements 9 Step 3: Specifying the Performance Metrics 10 Step 4: Specifying Constraints 10 Step 5: Specifying the Agency’s Current Methods in Use 13 Chapter 4  Evaluating Results 13 Interpreting the Recommendations 16 Managing Existing Scenarios 17 Using the Reference Guide 18 Chapter 5  Reviewing a Case Study 18 Overview 18 Role of the Transportation Planner 22 Role of the Travel Forecaster 29 Role of the Decision Maker 29 Outcome 30  Abbreviations, Acronyms, and Initialisms A-1 Appendix A  Methods Reference B-1 Appendix B  Programs Reference C-1 Appendix C  Requirements Reference D-1 Appendix D  Performance Metrics Reference E-1 Appendix E  Resources Reference C O N T E N T S