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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 Highwaysâ â¢â PlanningâandâForecastingâ â¢â PublicâTransportation Research sponsored by the American Association of State Highway and Transportation Officials in cooperation with the Federal Highway Administration
NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Systematic, well-designed research is the most effective way to solve many problems facing highway administrators and engineers. Often, highway problems are of local interest and can best be studied by highway departments individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation results in increasingly complex problems of wide inter- est to highway authorities. These problems are best studied through a coordinated program of cooperative research. Recognizing this need, the leadership of the American Association of State Highway and Transportation Officials (AASHTO) in 1962 ini- tiated an objective national highway research program using modern scientific techniquesâthe National Cooperative Highway Research Program (NCHRP). NCHRP is supported on a continuing basis by funds from participating member states of AASHTO and receives the full cooperation and support of the Federal Highway Administration, United States Department of Transportation. The Transportation Research Board (TRB) of the National Academies of Sciences, Engineering, and Medicine was requested by AASHTO to administer the research program because of TRBâs recognized objectivity and understanding of modern research practices. TRB is uniquely suited for this purpose for many reasons: TRB maintains an extensive com- mittee structure from which authorities on any highway transportation subject may be drawn; TRB possesses avenues of communications and cooperation with federal, state, and local governmental agencies, univer- sities, and industry; TRBâs relationship to the National Academies is an insurance of objectivity; and TRB maintains a full-time staff of special- ists in highway transportation matters to bring the findings of research directly to those in a position to use them. The program is developed on the basis of research needs identified by chief administrators and other staff of the highway and transporta- tion departments and by committees of AASHTO. Topics of the highest merit are selected by the AASHTO Standing Committee on Research (SCOR), and each year SCORâs recommendations are proposed to the AASHTO Board of Directors and the National Academies. Research projects to address these topics are defined by NCHRP, and qualified research agencies are selected from submitted proposals. Administra- tion and surveillance of research contracts are the responsibilities of the National Academies and TRB. The needs for highway research are many, and NCHRP can make significant contributions to solving highway transportation problems of mutual concern to many responsible groups. The program, however, is intended to complement, rather than to substitute for or duplicate, other highway research programs. Published research reports of the NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM are available from Transportation Research Board Business Office 500 Fifth Street, NW Washington, DC 20001 and can be ordered through the Internet by going to http://www.national-academies.org and then searching for TRB Printed in the United States of America NCHRP RESEARCH REPORT 852 Project 08-94 ISSN 2572-3766 (Print) ISSN 2572-3774 (Online) ISBN 978-0-309-44658-7 Library of Congress Control Number 2017953521 Â© 2017 National Academy of Sciences. All rights reserved. COPYRIGHT INFORMATION Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein. Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, FAA, FHWA, FMCSA, FRA, FTA, Office of the Assistant Secretary for Research and Technology, PHMSA, or TDC endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP. NOTICE The research report was reviewed by the technical panel and accepted for publication according to procedures established and overseen by the Transportation Research Board and approved by the National Academies of Sciences, Engineering, and Medicine. The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research and are not necessarily those of the Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; or the program sponsors. The Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; and the sponsors of the National Cooperative Highway Research Program do not endorse products or manufacturers. Trade or manufacturersâ names appear herein solely because they are considered essential to the object of the report.
The National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, non- governmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Marcia McNutt is president. The National Academy of Engineering was established in 1964 under the charter of the National Academy of Sciences to bring the practices of engineering to advising the nation. Members are elected by their peers for extraordinary contributions to engineering. Dr. C. D. Mote, Jr., is president. The National Academy of Medicine (formerly the Institute of Medicine) was established in 1970 under the charter of the National Academy of Sciences to advise the nation on medical and health issues. Members are elected by their peers for distinguished contributions to medicine and health. Dr. Victor J. Dzau is president. The three Academies work together as the National Academies of Sciences, Engineering, and Medicine to provide independent, objective analysis and advice to the nation and conduct other activities to solve complex problems and inform public policy decisions. The National Academies also encourage education and research, recognize outstanding contributions to knowledge, and increase public understanding in matters of science, engineering, and medicine. Learn more about the National Academies of Sciences, Engineering, and Medicine at www.national-academies.org. The Transportation Research Board is one of seven major programs of the National Academies of Sciences, Engineering, and Medicine. The mission of the Transportation Research Board is to increase the benefits that transportation contributes to society by providing leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisciplinary, and multimodal. The Boardâs varied committees, task forces, and panels annually engage about 7,000 engineers, scientists, and other transportation researchers and practitioners from the public and private sectors and academia, all of whom contribute their expertise in the public interest. The program is supported by state transportation departments, federal agencies including the component administrations of the U.S. Department of Transportation, and other organizations and individuals interested in the development of transportation. Learn more about the Transportation Research Board at www.TRB.org.
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 projectâs 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 PlanningâArea 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 âguidesâ 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 âNCHRP Web-Only Document 234â 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 ByâLawrenceâD.âGoldstein StaffâOfficer TransportationâResearchâBoard
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 agenciesâ 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 agencyâs 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: â¢ long-range planning â¢ performance-based planning â¢ safety â¢ project prioritization â¢ traffic impact study â¢ operational analyses â¢ pricing study â¢ air quality and climate change analyses â¢ transit analyses â¢ walk and bike activity forecasting â¢ freight planning â¢ environmental justice analyses â¢ economic impact analyses â¢ emergency management â¢ other planning issues that models are often asked to address Each of the planning and policy issues identified are coupled to a set of âinformation needs,â 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 1â Introduction 1 Project Objectives 2 Audience 2 Products 3 Report Contents 4 Chapter 2â GettingâStarted 4 Logging In 4 Home Page 5 General Settings 7 Chapter 3â BuildingâaâScenario 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 Agencyâs Current Methods in Use 13 Chapter 4â EvaluatingâResults 13 Interpreting the Recommendations 16 Managing Existing Scenarios 17 Using the Reference Guide 18 Chapter 5â ReviewingâaâCaseâStudy 18 Overview 18 Role of the Transportation Planner 22 Role of the Travel Forecaster 29 Role of the Decision Maker 29 Outcome 30â Abbreviations,âAcronyms,âandâInitialisms A-1 Appendix Aâ MethodsâReference B-1 Appendix Bâ ProgramsâReference C-1 Appendix Câ RequirementsâReference D-1 Appendix Dâ PerformanceâMetricsâReference E-1 Appendix Eâ ResourcesâReference C O N T E N T S