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NATIONAL NCHRP REPORT 618 COOPERATIVE HIGHWAY RESEARCH PROGRAM Cost-Effective Performance Measures for Travel Time Delay, Variation, and Reliability

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TRANSPORTATION RESEARCH BOARD 2008 EXECUTIVE COMMITTEE* OFFICERS CHAIR: Debra L. Miller, Secretary, Kansas DOT, Topeka VICE CHAIR: Adib K. Kanafani, Cahill Professor of Civil Engineering, University of California, Berkeley EXECUTIVE DIRECTOR: Robert E. Skinner, Jr., Transportation Research Board MEMBERS J. Barry Barker, Executive Director, Transit Authority of River City, Louisville, KY Allen D. Biehler, Secretary, Pennsylvania DOT, Harrisburg John D. Bowe, President, Americas Region, APL Limited, Oakland, CA Larry L. Brown, Sr., Executive Director, Mississippi DOT, Jackson Deborah H. Butler, Executive Vice President, Planning, and CIO, Norfolk Southern Corporation, Norfolk, VA William A.V. Clark, Professor, Department of Geography, University of California, Los Angeles David S. Ekern, Commissioner, Virginia DOT, Richmond Nicholas J. Garber, Henry L. Kinnier Professor, Department of Civil Engineering, University of Virginia, Charlottesville Jeffrey W. Hamiel, Executive Director, Metropolitan Airports Commission, Minneapolis, MN Edward A. (Ned) Helme, President, Center for Clean Air Policy, Washington, DC Will Kempton, Director, California DOT, Sacramento Susan Martinovich, Director, Nevada DOT, Carson City Michael D. Meyer, Professor, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta Michael R. Morris, Director of Transportation, North Central Texas Council of Governments, Arlington Neil J. Pedersen, Administrator, Maryland State Highway Administration, Baltimore Pete K. Rahn, Director, Missouri DOT, Jefferson City Sandra Rosenbloom, Professor of Planning, University of Arizona, Tucson Tracy L. Rosser, Vice President, Corporate Traffic, Wal-Mart Stores, Inc., Bentonville, AR Rosa Clausell Rountree, Executive Director, Georgia State Road and Tollway Authority, Atlanta Henry G. (Gerry) Schwartz, Jr., Chairman (retired), Jacobs/Sverdrup Civil, Inc., St. Louis, MO C. Michael Walton, Ernest H. Cockrell Centennial Chair in Engineering, University of Texas, Austin Linda S. Watson, CEO, LYNXCentral Florida Regional Transportation Authority, Orlando Steve Williams, Chairman and CEO, Maverick Transportation, Inc., Little Rock, AR EX OFFICIO MEMBERS Thad Allen (Adm., U.S. Coast Guard), Commandant, U.S. Coast Guard, Washington, DC Joseph H. Boardman, Federal Railroad Administrator, U.S.DOT Rebecca M. Brewster, President and COO, American Transportation Research Institute, Smyrna, GA Paul R. Brubaker, Research and Innovative Technology Administrator, U.S.DOT George Bugliarello, Chancellor, Polytechnic University of New York, Brooklyn, and Foreign Secretary, National Academy of Engineering, Washington, DC Sean T. Connaughton, Maritime Administrator, U.S.DOT LeRoy Gishi, Chief, Division of Transportation, Bureau of Indian Affairs, U.S. Department of the Interior, Washington, DC Edward R. Hamberger, President and CEO, Association of American Railroads, Washington, DC John H. Hill, Federal Motor Carrier Safety Administrator, U.S.DOT John C. Horsley, Executive Director, American Association of State Highway and Transportation Officials, Washington, DC Carl T. Johnson, Pipeline and Hazardous Materials Safety Administrator, U.S.DOT J. Edward Johnson, Director, Applied Science Directorate, National Aeronautics and Space Administration, John C. Stennis Space Center, MS William W. Millar, President, American Public Transportation Association, Washington, DC Nicole R. Nason, National Highway Traffic Safety Administrator, U.S.DOT James Ray, Acting Administrator, Federal Highway Administration, U.S.DOT James S. Simpson, Federal Transit Administrator, U.S.DOT Robert A. Sturgell, Acting Administrator, Federal Aviation Administration, U.S.DOT Robert L. Van Antwerp (Lt. Gen., U.S. Army), Chief of Engineers and Commanding General, U.S. Army Corps of Engineers, Washington, DC *Membership as of May 2008.

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NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM NCHRP REPORT 618 Cost-Effective Performance Measures for Travel Time Delay, Variation, and Reliability Cambridge Systematics, Inc. Oakland, CA Dowling Associates, Inc. Oakland, CA System Metrics Group, Inc. San Francisco, CA Texas Transportation Institute College Station, TX Subject Areas Planning and Administration Research sponsored by the American Association of State Highway and Transportation Officials in cooperation with the Federal Highway Administration TRANSPORTATION RESEARCH BOARD WASHINGTON, D.C. 2008 www.TRB.org

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NATIONAL COOPERATIVE HIGHWAY NCHRP REPORT 618 RESEARCH PROGRAM Systematic, well-designed research provides the most effective Project 07-15 approach to the solution of many problems facing highway ISSN 0077-5614 administrators and engineers. Often, highway problems are of local ISBN: 978-0-309-11741-8 interest and can best be studied by highway departments individually Library of Congress Control Number 2008905516 or in cooperation with their state universities and others. However, the 2008 Transportation Research Board 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 COPYRIGHT PERMISSION cooperative research. Authors herein are responsible for the authenticity of their materials and for obtaining In recognition of these needs, the highway administrators of the written permissions from publishers or persons who own the copyright to any previously American Association of State Highway and Transportation Officials published or copyrighted material used herein. initiated in 1962 an objective national highway research program Cooperative Research Programs (CRP) grants permission to reproduce material in this employing modern scientific techniques. This program is supported on 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, a continuing basis by funds from participating member states of the FMCSA, FTA, or Transit Development Corporation endorsement of a particular product, Association and it receives the full cooperation and support of the method, or practice. It is expected that those reproducing the material in this document for Federal Highway Administration, United States Department of 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 Transportation. from CRP. The Transportation Research Board of the National Academies was requested by the Association to administer the research program because of the Board's recognized objectivity and understanding of NOTICE modern research practices. The Board is uniquely suited for this purpose as it maintains an extensive committee structure from which 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 authorities on any highway transportation subject may be drawn; it the Governing Board of the National Research Council. Such approval reflects the possesses avenues of communications and cooperation with federal, Governing Board's judgment that the program concerned is of national importance and state and local governmental agencies, universities, and industry; its appropriate with respect to both the purposes and resources of the National Research Council. relationship to the National Research Council is an insurance of The members of the technical committee selected to monitor this project and to review this objectivity; it maintains a full-time research correlation staff of report were chosen for recognized scholarly competence and with due consideration for the specialists in highway transportation matters to bring the findings of balance of disciplines appropriate to the project. The opinions and conclusions expressed research directly to those who are in a position to use them. or implied are those of the research agency that performed the research, and, while they have been accepted as appropriate by the technical committee, they are not necessarily those of The program is developed on the basis of research needs identified the Transportation Research Board, the National Research Council, the American by chief administrators of the highway and transportation departments Association of State Highway and Transportation Officials, or the Federal Highway and by committees of AASHTO. Each year, specific areas of research Administration, U.S. Department of Transportation. needs to be included in the program are proposed to the National Each report is reviewed and accepted for publication by the technical committee according Research Council and the Board by the American Association of State to procedures established and monitored by the Transportation Research Board Executive Committee and the Governing Board of the National Research Council. Highway and Transportation Officials. Research projects to fulfill these needs are defined by the Board, and qualified research agencies are The Transportation Research Board of the National Academies, the National Research Council, the Federal Highway Administration, the American Association of State Highway selected from those that have submitted proposals. Administration and and Transportation Officials, and the individual states participating in the National surveillance of research contracts are the responsibilities of the National Cooperative Highway Research Program do not endorse products or manufacturers. Trade Research Council and the Transportation Research Board. or manufacturers' names appear herein solely because they are considered essential to the object of this report. 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

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COOPERATIVE RESEARCH PROGRAMS CRP STAFF FOR NCHRP REPORT 618 Christopher W. Jenks, Director, Cooperative Research Programs Crawford F. Jencks, Deputy Director, Cooperative Research Programs Lori L. Sundstrom, Senior Program Officer Eileen P. Delaney, Director of Publications Margaret B. Hagood, Editor NCHRP PROJECT 07-15 PANEL Field of Traffic--Area of Traffic Planning Charles E. Howard, Jr., Puget Sound Regional Council, Seattle, WA (Chair) Scott R. Drumm, Port of Portland (OR), Portland, OR Patricia S. Hu, Oak Ridge National Laboratory, Knoxville, TN Mark C. Larson, Minnesota DOT, St. Paul, MN Hani S. Mahmassani, University of Maryland, College Park, MD Phillip J. Mescher, Iowa DOT, Ames, IA Helen J. Rainwater, California DOT, Sacramento, CA Steven A. Smith, San Bernardino Associated Governments, San Bernardino, CA Ralph A. Gillmann, FHWA Liaison Mark R. Norman, TRB Liaison

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FOREWORD By Lori L. Sundstrom Staff Officer Transportation Research Board State departments of transportation, metropolitan planning organizations, public tran- sit authorities, and other transportation stakeholders increasingly are turning to the use of transportation system performance measures to gain and sustain public and legislative support for investments in managing, maintaining, and constructing transportation infra- structure. Measures that express congestion and mobility in terms that system users can understand and use are needed for use in systems planning, corridor development, priority programming, and operations to inform investment decisions directed at improving system performance. This report presents a framework and cost-effective methods to predict, mea- sure, and report travel time, delay, and reliability from a customer-oriented perspective. The use of travel time, delay, and reliability as performance measures is hampered by complex data requirements, data accuracy issues, and inadequate procedures for incorpo- rating these measures into the transportation planning process. Few states have invested in comprehensive data collection programs because these measures can be expensive and difficult to generate. A relatively small number of public agencies have the data collection programs or analytical forecasting capabilities to generate reliable estimates of these mea- sures. States that do collect this data typically do so for select corridors, and their sample sizes are typically quite small. There is a need for structured, cost-effective measures of travel time, delay, and reliability that can be used by practitioners in predicting, measuring, mon- itoring, and reporting transportation performance in support of system investment and management decisions. The purpose of this guidebook is to provide transportation planners and project programmers with a framework to predict system performance using cost-effective data collection methods, analysis approaches, and applications that most effectively support transportation planning and decision making for capital and operational investments for quality-of-service monitoring and evaluation.

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CONTENTS 1 Summary 4 Chapter 1 Introduction 4 1.1 Why Measure Travel-Time Performance? 5 1.2 How to Use the Guidebook 6 1.3 Limitations of the Guidebook 6 1.4 Measuring Mobility and Reliability 10 Chapter 2 Selecting Appropriate Performance Measures 10 2.1 Introduction 10 2.2 Measure Selection 13 2.3 Performance Measure Summary 13 2.4 Individual Measures 17 2.5 Area Measures 18 2.6 Basic Data Elements 19 2.7 Definition and Discussion of Speed Terms 20 2.8 Other Data Elements 21 2.9 Time Periods for Analysis 22 2.10 The Right Measure for the Analysis Area 22 2.11 The Right Measure for the Type of Analysis 23 2.12 Index Measure Considerations 25 Chapter 3 Data Collection and Processing 25 3.1 Introduction 25 3.2 Data Collection Methods 25 3.3 Data Collection Sampling Plan 30 3.4 Collecting Data from TMCs 32 3.5 Processing/Quality Control 34 Chapter 4 Before/After Studies 34 4.1 Introduction 35 4.2 Common Pitfalls of Before/After Studies 35 4.3 Selection of Performance Measures for Before/After Studies 35 4.4 Determining if Conditions Are Significantly Better 36 4.5 What to Do If the Null Hypothesis Cannot Be Rejected 37 Chapter 5 Identification of Deficiencies 37 5.1 Introduction 37 5.2 Quantifying Agency Standards 37 5.3 Data Collection 37 5.4 Comparing Field Data to Performance Standards 39 5.5 Comparing Forecasted Performance to Performance Standards 39 5.6 Diagnosing the Causes

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41 Chapter 6 Forecast Future Performance 41 6.1 Introduction 41 6.2 Estimating/Forecasting Travel Time 48 6.3 Estimating Delay 48 6.4 Estimating Reliability 51 Chapter 7 Alternatives Analysis 51 7.1 Introduction 51 7.2 Defining the Problem 52 7.3 Generation of Project Alternatives for Analysis 53 7.4 Selection of Performance Measures 53 7.5 Evaluation of Alternatives 54 7.6 Develop Improvement Program 54 7.7 Evaluate Effectiveness of Implemented Solutions 55 Chapter 8 Using Travel Time Data in Planning and Decision Making 55 8.1 Introduction 55 8.2 Scope and Limitations 55 8.3 Organization 55 8.4 Creating a Performance-Based Decision-Making Environment 59 8.5 Using Travel Time, Delay, and Reliability in Planning Applications 59 8.6 Typical Planning Applications 69 References