Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
2019 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 925 Estimating the Value of Truck Travel Time Reliability Sebastian E. Guerrero Ira Hirschman Joseph G. B. Bryan WSP Washington, DC Robert B. Noland RutgeRS univeRSity New Brunswick, NJ Stan Hsieh Abt ASSociAteS New York, NY David Schrank Shuang âBobieâ Guo texAS A&M tRAnSPoRtAtion inStitute College Station, TX Subscriber Categories Motor Carriers â¢ Economics â¢ Freight Transportation 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, and implementable research is the most effective way to solve many problems facing state departments of transportation (DOTs) administrators and engineers. Often, highway problems are of local or regional interest and can best be studied by state DOTs individually or in cooperation with their state universities and others. However, the accelerating growth of highway transporta- tion results in increasingly complex problems of wide interest to high- way 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 transportation departments, by committees of AASHTO, and by the Federal Highway Administration. Topics of the highest merit are selected by the AASHTO Special Committee on Research and Innovation (R&I), and each year R&Iâs recommendations are proposed to the AASHTO Board of Direc- tors and the National Academies. Research projects to address these topics are defined by NCHRP, and qualified research agencies are selected from submitted proposals. Administration 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 925 Project 07-24 ISSN 2572-3766 (Print) ISSN 2572-3774 (Online) ISBN 978-0-309-48088-8 Library of Congress Control Number 2019953010 Â© 2019 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. John L. Anderson 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 provide leadership in transportation improvements and innovation through trusted, timely, impartial, and evidence-based information exchange, research, and advice regarding all modes of transportation. The Boardâs varied activities annually engage about 8,000 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 CRP STAFF FOR NCHRP RESEARCH REPORT 925 Christopher J. Hedges, Director, Cooperative Research Programs Lori L. Sundstrom, Deputy Director, Cooperative Research Programs William C. Rogers, Senior Program Officer Jarrel McAfee, Senior Program Associate Eileen P. Delaney, Director of Publications Natalie Barnes, Associate Director of Publications Janet M. McNaughton, Senior Editor NCHRP PROJECT 07-24 PANEL Field of TrafficâArea of Traffic Planning Barry C. Padilla, Sacramento, CA (Chair) Sondra D. Johnson, Texas DOT, Austin, TX Charles H. W. Edwards, North Carolina DOT, Raleigh, NC Mihalis Golias, University of Memphis, Memphis, TN Jesse D. Gwilliams, Michigan DOT, Lansing, MI Subrat Mahapatra, Maryland State Highway Administration, Baltimore, MD Caroline A. Mays, Texas DOT, Austin, TX Thomas E. McQueen, Georgia DOT, Atlanta, GA Wenjuan Zhao, Washington State DOT, Olympia, WA Ali Zockaie, Michigan State University, East Lansing, MI Birat Pandey, FHWA Liaison Scott Babcock, TRB Liaison
NCHRP Research Report 925: Estimating the Value of Truck Travel Time Reliability pro- vides planners and analysts a Reliability Valuation Framework that is applicable to urban or intercity shipments around the United States across a range of truck freight users and commodity types. Reliability was measured and modeled as the 95th percentile delay, which was defined as the difference between the 95th percentile travel time and the expected travel time. This measure of reliability has various advantages over other measures: it is easy to communicate to shippers and motor carriers, has desirable modeling properties, and is compatible with the Travel Time Index, which is the measure of reliability most commonly used in the United States. Travel time reliability is frequently cited as an important metric for the trucking com- munity and users of truck freight services. While the travel time reliability for trucking is commonly measured, truck reliability is seldom considered in the benefitâcost evaluation of mobility projects, which underrepresents the benefits accrued to freight users of the roadway system. For NCHRP Project 07-24, WSP was asked to develop an improved framework for the valuation of truck freight reliability. The framework included the methodology, modeling assumptions, analytical techniques, and tools developed in NCHRP Report 824 to assist transportation professionals and decision-makers in the evaluation of proposed roadway infrastructure and operations investments. The Reliability Valuation Framework has the following components: â¢ Measurement. It provides guidance on how to distinguish between different types of variability in travel time data and isolates the variability that causes unreliability in ship- ment delivery schedules. Practical guidance is also provided on how to estimate route travel times from link data, so that reliability can be measured from the perspective of system users. â¢ Reliability modeling. It relies on previously estimated statistical relationships between average travel times and 95th percentile travel times in different roadway conditions. Guidance is also provided for analysts and planners to estimate their own statistical rela- tionships using local data. â¢ Valuation. It recommends how to use the value of reliability and the value of time in three common planning analyses: benefitâcost project evaluation, system-level performance measurement, and bottleneck identification. F O R E W O R D By William C. Rogers Staff Officer Transportation Research Board
1 Chapter 1 Introduction 1 1.1 Public Sector Challenge 2 1.2 Value of Reliability 2 1.3 Research Objective 3 1.4 Target Audience 3 1.5 Report Organization 4 Chapter 2 Background 4 2.1 Travel Time Unreliability 10 2.2 Estimating Freight VOR 16 Chapter 3 Stated-Preference Survey 16 3.1 Overview 18 3.2 Experimental Design 18 3.3 Survey Administration 20 3.4 Responses 22 Chapter 4 Modeling 22 4.1 Theory 26 4.2 Exploratory Statistical Models 32 4.3 Subgroup Models 36 4.4 VOT and VOR Estimates 39 Chapter 5 Reliability Valuation Framework 39 5.1 Introduction 42 5.2 Measurement 49 5.3 Reliability Modeling 54 5.4 Valuation 55 5.5 Planning Applications 60 Chapter 6 Case Study 60 6.1 Bottleneck Identification 63 6.2 Project Evaluation 68 Chapter 7 Conclusions 68 7.1 VOR Estimates 69 7.2 Freight Planning Applications 69 7.3 Lessons Learned in Surveying and Modeling C O N T E N T S
71 Abbreviations and Acronyms 72 References 75 Appendix A Stated-Preference Survey Design 90 Appendix B Survey Responses 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.