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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 REPORT 716 Travel Demand Forecasting: Parameters and Techniques Cambridge Systematics, Inc. Cambridge, MA Vanasse Hangen Brustlin, Inc. Silver Spring, MD Gallop Corporation Rockville, MD Chandra R. Bhat Austin, TX Shapiro Transportation Consulting, LLC Silver Spring, MD Martin/Alexiou/Bryson, PLLC Raleigh, NC Subscriber Categories Highways â¢ Operations and Traffic Management â¢ Planning and Forecasting â¢ Safety and Human Factors TRANSPORTAT ION RESEARCH BOARD WASHINGTON, D.C. 2012 www.TRB.org 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 provides the most effective approach to the solution of 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 develops increasingly complex problems of wide interest to highway authorities. These problems are best studied through a coordinated program of cooperative research. In recognition of these needs, the highway administrators of the American Association of State Highway and Transportation Officials initiated in 1962 an objective national highway research program employing modern scientific techniques. This program is supported on a continuing basis by funds from participating member states of the Association and it receives the full cooperation and support of the Federal Highway Administration, United States Department of Transportation. The Transportation Research Board of the National Academies was requested by the Association to administer the research program because of the Boardâs recognized objectivity and understanding of modern research practices. The Board is uniquely suited for this purpose as it maintains an extensive committee structure from which authorities on any highway transportation subject may be drawn; it possesses avenues of communications and cooperation with federal, state and local governmental agencies, universities, and industry; its relationship to the National Research Council is an insurance of objectivity; it maintains a full-time research correlation staff of specialists in highway transportation matters to bring the findings of research directly to those who are in a position to use them. The program is developed on the basis of research needs identified by chief administrators of the highway and transportation departments and by committees of AASHTO. Each year, specific areas of research needs to be included in the program are proposed to the National Research Council and the Board by the American Association of State Highway and Transportation Officials. Research projects to fulfill these needs are defined by the Board, and qualified research agencies are selected from those that have submitted proposals. Administration and surveillance of research contracts are the responsibilities of the National Research Council and the Transportation Research Board. The needs for highway research are many, and the National Cooperative Highway Research Program can make significant contributions to the solution of 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 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 at: http://www.national-academies.org/trb/bookstore Printed in the United States of America NCHRP REPORT 716 Project 08-61 ISSN 0077-5614 ISBN 978-0-309-21400-1 Library of Congress Control Number 2012935156 Â© 2012 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, FTA, or Transit Development Corporation 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 project that is the subject of this report was a part of the National Cooperative Highway Research Program, conducted by the Transportation Research Board with the approval of the Governing Board of the National Research Council. The members of the technical panel selected to monitor this project and to review this report were chosen for their special competencies and with regard for appropriate balance. The 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 Governing Board of the National Research Council. 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 Research Council, or the program sponsors. The Transportation Research Board of the National Academies, the National Research Council, 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 is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. On the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Ralph J. Cicerone is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Charles M. Vest is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, on its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academyâs purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Ralph J. Cicerone and Dr. Charles M. Vest are chair and vice chair, respectively, of the National Research Council. The Transportation Research Board is one of six major divisions of the National Research Council. The mission of the Transporta- tion Research Board is to provide leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisciplinary, and multimodal. The Boardâs varied activities 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 individu- als interested in the development of transportation. www.TRB.org www.national-academies.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 project reported herein was performed under NCHRP Project 8-61 by Cambridge Systematics, Inc. in association with Dr. Chandra R. Bhat, Vanasse Hangen Brustlin, Inc., Martin/ Alexiou/Bryson, PLLC, Gallop Corporation, and Shapiro Transportation Consulting, LLC. Cambridge Systematics served as prime contractor. Thomas Rossi of Cambridge Systematics served as project director and principal investigator. Major roles in this project were also performed by David Kurth, John (Jay) Evans, Daniel Beagan, Bruce Spear, Robert Schiffer, and Ramesh Thammiraju of Cambridge Systematics; Dr. Chandra Bhat; Richard Roisman, formerly of Vanasse Hangen Brustlin; Philip Shapiro of Shapiro Transportation Consulting (formerly of Vanasse Hangen Brustlin); C.Y. Jeng of Gallop Corporation; William Martin of Martin/Alexiou/Bryson; and Amlan Banerjee and Yasasvi Popuri, formerly of Cambridge Systematics. A peer review panel provided valuable comments on the draft report. The research team wishes to thank the peer review panel members: Charles Baber of the Baltimore Metropolitan Council, Bart Benthul of the Bryan-College Station Metropolitan Planning Organization (MPO), Mike Conger of the Knoxville Regional Transportation Planning Organization, Ken Kaltenbach of the Corradino Group, Phil Matson of the Indian River MPO, Phil Mescher of the Iowa Department of Transportation, Jeremy Raw of the Federal Highway Administration, and David Schmitt of AECOM. The research team wishes to thank the following organizations and individuals for their assistance: Nancy McGuckin, Ron Milone of the Metropolitan Washington Council of Governments, and Jeffrey Agee-Aguayo of the Sheboygan MPO. CRP STAFF FOR NCHRP REPORT 716 Christopher W. Jenks, Director, Cooperative Research Programs Crawford F. Jencks, Deputy Director, Cooperative Research Programs Nanda Srinivasan, Senior Program Officer Charlotte Thomas, Senior Program Assistant Eileen P. Delaney, Director of Publications Natalie Barnes, Senior Editor NCHRP PROJECT 08-61 PANEL Field of Transportation PlanningâArea of Forecasting Thomas J. Kane, Thomas J. Kane Consulting, Urbandale, IA (Chair) Michael S. Bruff, North Carolina DOT, Raleigh, NC Ed J. Christopher, Berwyn, IL Nathan S. Erlbaum, New York State DOT, Albany, NY Jerry D. Everett, University of Tennessee, Knoxville, TN Bruce Griesenbeck, Sacramento Area Council of Governments, Sacramento, CA Herbert S. Levinson, Wallingford, CT Richard H. Pratt, Richard H. Pratt, Consultant, Inc., Garrett Park, MD Bijan Sartipi, California DOT, Oakland, CA Shuming Yan, Washington State DOT, Seattle, WA Ken Cervenka, FTA Liaison Kimberly Fisher, TRB Liaison
F O R E W O R D This report is an update to NCHRP Report 365: Travel Estimation Techniques for Urban Planning and provides guidelines on travel demand forecasting procedures and their application for solving common transportation problems. The report presents a range of approaches that allow users to determine the level of detail and sophistication in select- ing modeling and analysis techniques most appropriate to their situations and addresses straight-forward techniques, optional use of default parameters, and appropriate references to other more sophisticated techniques. In 1978, TRB published NCHRP Report 187: Quick-Response Urban Travel Estimation Techniques and Transferable Parameters. This report described default parameters, factors, and manual techniques for doing simple planning analysis. The report and its default data were used widely by the transportation planning profession for almost 20 years. In 1998, drawing on several newer data sources including the 1990 Census and National Personal Household Travel Survey, an update to NCHRP Report 187 was published as NCHRP Report 365: Travel Estimation Techniques for Urban Planning. Since NCHRP Report 365 was published, significant changes have occurred affecting the complexity, scope, and context of transportation planning. Planning concerns have grown beyond âurbanâ to include rural, statewide, and special-use lands. Transportation planning tools have evolved and proliferated, enabling improved and more flexible analyses to support decisions. The demands on transportation planning have expanded into special populations (e.g., tribal, immigrant, older, and young) and broader issues (e.g., safety, congestion, pricing, air quality, environment, and freight). In addition, the default data and parameters in NCHRP Report 365 needed to be updated to reflect the planning requirements of today and the next 10 years. Thus, the objective of this research was to revise and update NCHRP Report 365 to reflect current travel characteristics and to provide guidance on travel demand forecasting procedures and their application for solving common transportation problems. The research was performed by Cambridge Systematics, Inc. in association with Vanasse Hangen Brustlin, Inc., Gallop Corporation, Dr. Chandra R. Bhat, Shapiro Transportation Consulting, LLC, and Martin/Alexiou/Bryson, PLLC. Information was gathered via liter- ature review, interviews with practitioners, and a database of parameters collected from metropolitan planning organizations as well as from the 2009 National Household Travel Survey. Planners can make use of the information presented in this report in two primary ways: (1) to develop travel model components when local data suitable for model develop- ment are insufficient or unavailable and (2) to check the reasonableness of model outputs. By Nanda Srinivasan Staff Officer Transportation Research Board
C O N T E N T S 1 Chapter 1 Introduction 1 1.1 Background 2 1.2 Travel Demand Forecasting: Trends and Issues 3 1.3 Overview of the Four-Step Travel Modeling Process 5 1.4 Summary of Techniques and Parameters 5 1.5 Model Validation and Reasonableness Checking 5 1.6 Advanced Travel Analysis Procedures 5 1.7 Case Study Applications 5 1.8 Glossary of Terms Used in This Report 7 Chapter 2 Planning Applications Context 7 2.1 Types of Planning Analyses 10 2.2 Urban Area Characteristics Affecting Planning and Modeling 14 Chapter 3 Data Needed for Modeling 14 3.1 Introduction 14 3.2 Socioeconomic Data and Transportation Analysis Zones 18 3.3 Network Data 24 3.4 Validation Data 27 Chapter 4 Model Components 27 4.1 Introduction 31 4.2 The Logit Model 33 4.3 Vehicle Availability 37 4.4 Trip Generation 43 4.5 Trip Distribution 48 4.6 External Travel 53 4.7 Mode Choice 58 4.8 Automobile Occupancy 62 4.9 Time of Day 65 4.10 Freight/Truck Modeling 72 4.11 Highway Assignment 77 4.12 Transit Assignment 80 Chapter 5 Model Validation and Reasonableness Checking 80 5.1 Introduction 80 5.2 Model Validation Overview 81 5.3 Model Validation and Reasonableness Checking Procedures for Existing Models 86 5.4 Model Validation and Reasonableness Checking Procedures for Models or Model Components Developed from Information Contained in Chapter 4 88 5.5 Cautions Regarding Use of This Report for Validation
89 Chapter 6 Emerging Modeling Practices 90 6.1 The Activity-Based Approach 92 6.2 Activity-Based Travel Model Systems in Practice 96 6.3 Integration with Other Model Systems 99 6.4 Summary 100 Chapter 7 Case Studies 100 7.1 Introduction 100 7.2 Model Reasonableness Check 108 7.3 Model Development Case Study for a Smaller Area without Data for Model Estimation 114 References A-1 Appendix A Federal Planning and Modeling Requirements B-1 Appendix B Review of Literature on Transferability Studies C-1 Appendix C Transferable Parameters Note: Many of the photographs, figures, and tables in this report 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.