Measuring, Characterizing, and Reporting Pavement Roughness of Low-Speed and Urban Roads (2019)

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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 914 Measuring, Characterizing, and Reporting Pavement Roughness of Low-Speed and Urban Roads Steven M. Karamihas Mark E. Gilbert The UniversiTy of Michigan TransporTaTion research insTiTUTe Ann Arbor, MI Michelle A. Barnes gis Linking The Layers Ann Arbor, MI Rohan W. Perera sMe Plymouth, MI Subscriber Categories Materials • Pavements 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 techniques—the 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 TRB’s 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; TRB’s 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&I’s 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 914 Project 10-93 ISSN 2572-3766 (Print) ISSN 2572-3774 (Online) ISBN 978-0-309-48060-4 Library of Congress Control Number 2019945986 © 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. 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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 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 Board’s 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 reported herein was performed under NCHRP Project 10-93 by the University of Michigan Transportation Research Institute (UMTRI) with cooperation from SME. Steven M. Karamihas, Research Area Specialist at UMTRI, was the Project Director and Principal Investigator. Dr. Rohan W. Perera, a Senior Consultant at SME, assisted Steven Karamihas in the research. In addition to Dr. Perera, Dr. Abdalla Al-Rawashdeh from SME helped plan and execute the experimental work. Several members of the UMTRI staff contributed to the research. Michelle Barnes provided geographic information system expertise for the project and helped develop the research approach. Mark Gilbert, a lead electronics engineer, supervised the design, fabrication, and application of instrumentation for the research. Mich Rasulis, Scott Bogard, and Bob Goodsell developed data collection and data analysis soft- ware. Mike Campbell, Dan Huddleson, John Koch, and Ken Winzeler fabricated the instrumentation and assisted with its design. Rob Gessner, Mike Campbell, Dan Huddleson, Nick Kotsch, and Mich Rasulis helped execute the experiments. CRP STAFF FOR NCHRP RESEARCH REPORT 914 Christopher J. Hedges, Director, Cooperative Research Programs Lori L. Sundstrom, Deputy Director, Cooperative Research Programs Amir N. Hanna, Senior Program Officer Eileen P. Delaney, Director of Publications Natalie Barnes, Associate Director of Publications Heidi Willis, Editor NCHRP PROJECT 10-93 PANEL Field of Materials and Construction—Area of Specifications, Procedures, and Practices James C. Watkins, Forest Service, Jackson, MS (Chair) David L. Huft, South Dakota DOT, Pierre, SD Mike M. Ecmecian, Massachusetts DOT, Hopkinton, MA Affan Habib, Virginia DOT, Richmond, VA Kent R. Hansen, Gambrills, MD Qing Lu, University of South Florida, Tampa, FL Kevin W. McMullen, Wisconsin Concrete Pavement Association, Madison, WI Brian L. Schleppi, Ohio DOT, Columbus, OH Mark K. Wheeler, Idaho Transportation Department, Boise, ID Robert Orthmeyer, FHWA Liaison Nelson H. Gibson, TRB Liaison (continued on page vi)

F O R E W O R D By Amir N. Hanna Staff Officer Transportation Research Board This report reviews the practices for roughness measurement and the unique features of urban and low-speed roadways, and it evaluates the use of existing inertial profilers for such measurements. The report also proposes revisions to AASHTO standard specifica- tions and practices addressing inertial profiler certification and operations. The informa- tion contained in the report will be of immediate interest to state materials and pavement engineers and others involved in the different aspects of pavement condition monitoring and evaluation. Pavement smoothness (or roughness) is used by state highway agencies for monitoring network condition and other purposes such as assessing construction quality and optimiz- ing investments in preservation, rehabilitation, and reconstruction. States are also required to report the International Roughness Index (IRI) as an element of the federal Highway Performance Monitoring System (HPMS). Because IRI is not measured directly but is cal- culated as the mechanical response of a generic quarter-car, traveling at 50 mph, to the elevation profile of the roadway, there are concerns about using current practices for esti- mating roughness of low-speed and urban roads. Urban roadways contain unique features such as drainage provisions, sudden grade changes, and crowned intersecting streets. These features are included in the elevation profile and interpreted as roughness. Also, because IRI calculation is based on the speed- and profile-dependent mechanical response, the cal- culated IRI at a slower speed will vary depending on the nature of the roadway elevation profile and the chosen speed. In addition, changes in travel speed and stops or near-stops can further distort, or even invalidate, the measured elevation profile. Because of the unique features of low-speed and urban roads, research was needed to identify or, if necessary, develop means for appropriately measuring, characterizing and reporting pavement roughness of these roads. Such means will help highway agencies obtain reliable information for use in monitoring pavement performance, evaluating con- struction quality, planning and making investment decisions, and interpreting national data (especially the HPMS). Under NCHRP Project 10-93, “Measuring, Characterizing, and Reporting Pavement Roughness of Low-Speed and Urban Roads,” the research team led by the University of Michigan worked with the objective of identifying/developing a means for measuring, characterizing, and reporting pavement roughness on low-speed and urban roads. To accomplish this objective, the research team reviewed the practices for roughness mea- surement and the unique features of urban and low-speed roadways and conducted field experiments to evaluate the use of existing inertial profilers for such measurements. Based on the finding of this evaluation, the research team proposed revisions to AASHTO

Standard Specification for Inertial Profiler, AASHTO Standard Practice for Certification of Inertial Profiling Systems, and AASHTO Standard Practice for Operating Inertial Profilers and Evaluating Pavement Profiles. This report summarizes the work performed in the project and includes proposed revi- sions to AASHTO standard specifications and practices addressing inertial profiler certifica- tion and operation as well as several appendices that provide further details on the different aspects of the research. The authors would like to thank several other organizations that provided resources for the project. The Pennsylvania Department of Transportation (DOT) provided profile data and images for urban pave- ment collected as part of their network pavement condition survey. The New Jersey DOT provided profile data, images, and straight-line diagrams for quality assurance measurements on urban and low-speed roadways. The Minnesota DOT provided access to the MnROAD research facility for testing and assisted with reference measurements of one of the test sections. The Minnesota DOT, Surface Systems and Instru- ments, Inc. (SSI), Dynatest, Ames Engineering, the South Dakota DOT, and the Iowa DOT sent profilers to MnROAD to collect data for the experiments and provided operators to execute the testing. The West- ern Federal Lands Highway Division of the Federal Highway Administration permitted the use of profile measurement equipment fabricated for other research in this project. The Hyundai Motor Company provided a vehicle for testing. Several individuals at these organizations provided their time to the project. They were Colin McClenahen, John Van Sickle, and Ty Reed of the Pennsylvania DOT; Susan Gresavage of the New Jersey DOT; Gary Wallner, Tom Nordstrom, Ben Worel, and Jack Herndon of the Minnesota DOT; Chris Koos and Justin Cook of the South Dakota DOT; Jason Omundson and Ricardo Corona of the Iowa DOT; Nick Schaefer from SSI; Bob Briggs and Don Noah from Dynatest; and Dustin Reid from Ames Engineering. AUTHOR ACKNOWLEDGMENTS (Continued)

C O N T E N T S 1 Summary 1 Measurement 2 Characterization 2 Reporting 4 Chapter 1 Introduction and Research Approach 4 1.1 Problem Statement 4 1.2 Research Objective 4 1.3 Scope 5 1.3.1 Profiler Operating Speed 5 1.3.2 Profiler Operating Environment 5 1.3.3 Roughness Index 6 1.3.4 Built-In Roughness 6 1.4 Research Approach 6 1.4.1 Study Urban and Low-Speed Roadway Features 6 1.4.2 Validate Technology for Urban and Low-Speed Profile Measurement 7 1.4.3 Recommend a Method for Quantifying Roughness on Urban and Low-Speed Roadways 7 1.4.4 Develop a Framework for Reporting Roughness in Urban Areas 7 1.5 Organization of the Report 9 Chapter 2 Features on Urban and Low-Speed Roadways 10 2.1 Data Sources 10 2.2 Built-in Roughness 10 2.2.1 Roughness Profiles 11 2.2.2 Localized Roughness 12 2.2.3 Compound Events 14 2.2.4 Idealized Profiles 17 2.2.5 Distributed Roughness 18 2.3 Measurement Issues 18 2.3.1 Transverse Variations 19 2.3.2 High-Pass Filtering 20 2.3.3 Low-Pass Filtering 21 2.3.4 Spikes 22 2.3.5 Operational Difficulties 22 2.4 Feature Identification

26 Chapter 3 Evaluation of Existing Inertial Profilers for Use on Urban and Low-Speed Roadways 26 3.1 Background 28 3.2 Field Experiment 28 3.2.1 Test Sections 28 3.2.2 Profilers 29 3.2.3 Reference Measurements 29 3.2.4 Speed/Location Measurement 29 3.2.5 Test Conditions 30 3.3 Data Processing 30 3.3.1 GPS Data 30 3.3.2 Profile Data 30 3.4 Results 30 3.4.1 Transverse Profile Variations 32 3.4.2 Constant Speed Operation 34 3.4.3 Coasting 34 3.4.4 Braking 39 3.4.5 Throttling 40 3.4.6 Stop-and-Go Operation 45 3.4.7 Operation from a Dead Stop 46 3.4.8 Operation on a Curve 47 3.4.9 Longitudinal Distance Measurement 49 Chapter 4 Ride Experiment 49 4.1 Field Experiment 49 4.1.1 Test Sections 49 4.1.2 Test Vehicles 49 4.1.3 Instrumentation 51 4.1.4 Test Conditions 51 4.2 Data Processing 51 4.2.1 Ride Sensor Processing 53 4.2.2 Roughness Indices 55 4.3 Results, Overall Roughness 55 4.3.1 IRI 55 4.3.2 Mean Roughness Index (MRI) 55 4.3.3 Ride Number 57 4.3.4 Golden Car Indices 59 4.3.5 Discussion 61 4.4 Results, Localized Roughness 67 Chapter 5 Summary, Findings, and Recommendations for Future Research 67 5.1 Summary of the Research and Primary Findings 67 5.1.1 Measurement Accuracy 69 5.1.2 Characterization 70 5.1.3 Profile Features 70 5.2 Recommendations 70 5.2.1 Measurement 72 5.2.2 Characterization 72 5.2.3 Reporting 74 5.3 Suggestions for Future Research

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. 76 References 78 Acronyms 80 Attachment 1 Proposed Changes To AASHTO Specifications 80 AASHTO M 328 82 AASHTO R 56 83 AASHTO R 57 A-1 Appendix A Examples of Roughness at Built-In Road Features B-1 Appendix B Experimental Evaluation of Inertial Profilers for Use on Urban and Low-Speed Roadways B-1 B.1 Test Sections B-5 B.2 Profilers B-8 B.3 Reference Measurements B-8 B.4 Speed/Location Measurement B-9 B.5 Driver Instructions B-12 B.6 GPS Data Processing B-15 B.7 Cross Correlation of Constant-Speed Runs B-21 B.8 References C-1 Appendix C Ride Experiment C-1 C.1 Test Vehicles C-3 C.2 Instrumentation C-15 C.3 Test Procedure C-16 C.4 Test Sections C-19 C.5 References