Connected and Autonomous Vehicle Technology: Determining the Impact on State DOT Maintenance Programs (2024)

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2024 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 1084 Connected and Autonomous Vehicle Technology DETERMINING THE IMPACT ON STATE DOT MAINTENANCE PROGRAMS Shauna Hallmark Omar Smadi Institute for Transportation Iowa State University Ames, IA Jon Markt Eric Plapper HDR Omaha, NE Paul Carlson Automated Roads Greensboro, NC Katie Zimmerman Greg Duncan Applied Pavement Technology, Inc. Urbana, IL Subscriber Categories Maintenance and Preservation • Operations and Trafc Management • Vehicles and Equipment Research sponsored by the American Association of State Highway and Transportation Ofcials 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 (FHWA), United States Department of Transportation, under Agree- ment No. 693JJ31950003. 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 iden- tified by chief administrators and other staff of the highway and transportation departments, by committees of AASHTO, and by the FHWA. 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 https://www.mytrb.org/MyTRB/Store/default.aspx Printed in the United States of America NCHRP RESEARCH REPORT 1084 Project 14-42 ISSN 2572-3766 (Print) ISSN 2572-3774 (Online) ISBN 978-0-309-70943-9 Library of Congress Control Number 2024930791 © 2024 by the National Academy of Sciences. National Academies of Sciences, Engineering, and Medicine and the graphical logo are trade- marks of the 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, APTA, FAA, FHWA, FTA, GHSA, or NHTSA 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; the FHWA; or the program sponsors. The Transportation Research Board does not develop, issue, or publish standards or spec- ifications. The Transportation Research Board manages applied research projects which provide the scientific foundation that may be used by Transportation Research Board sponsors, industry associations, or other organizations as the basis for revised practices, procedures, or specifications. 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. 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e 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. e 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. e 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. e 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. e 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.nationalacademies.org. e Transportation Research Board is one of seven major program divisions of the National Academies of Sciences, Engineering, and Medicine. e mission of the Transportation Research Board is to mobilize expertise, experience, and knowledge to anticipate and solve complex transportation-related challenges. e Board’s varied activities annually engage about 8,500 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. e 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 National Cooperative Highway Research Program (NCHRP) Project 14-42 by the Institute for Transportation (InTrans) at Iowa State University (ISU). ISU was the contractor for this study, with HDR, Automated Roads, and Applied Pavement Technology, Inc. serving as subcontractors. The authors would like to acknowledge the many individuals and organizations that made this research project possible. In particular, the panel would like to thank the various departments of transportation who participated in the survey and targeted interviews. CRP STAFF FOR NCHRP RESEARCH REPORT 1084 Waseem Dekelbab, Deputy Director, Cooperative Research Programs, and Manager, National Cooperative Highway Research Program Camille Crichton-Sumners, Senior Program Officer Mazen Alsharif, Senior Program Assistant Natalie Barnes, Director of Publications Heather DiAngelis, Associate Director of Publications Alison Shapiro, Editor NCHRP PROJECT 14-42 PANEL Field of Maintenance—Area of Maintenance of Way and Structures Mylinh Lidder, Nevada DOT (retired), Reno, NV (Chair) David L. Bergner, Monte Vista Associates, LLC, Mesa, AZ Matthew J. A. Buckley, Whitman, Requardt and Associates, LLP, Wilmington, DE Luke A. Lorrimer, Maine Department of Transportation, Augusta, ME Nadereh Moini, New Jersey Sports & Exposition Authority, Lyndhurst, NJ Kuilin Zhang, Michigan Technological University, Houghton, MI Morgan Kessler, FHWA Liaison

NCHRP Research Report 1084 provides an overview into how the implementation of connected and autonomous vehicle (CAV) technology will likely impact the state of prac- tice for maintenance programs within state departments of transportation (DOTs). The report will be of interest to those responsible for intelligent transportation systems (ITS), trans portation systems management and operations (TSMO) programs, maintenance of transportation assets, and practitioners interested in the deployment of CAV technologies within state DOT rights-of-way. The transportation industry is examining how roadway appurtenances such as traffic control devices, markings, signals, guardrail, computing systems, communications infrastruc- ture, and other permanent and temporary devices can be used to facilitate the operation of CAVs. The diffusion of CAV technologies impacts state transportation agencies, which often have constrained budgets and workforces. The quick pace of CAV technology obsolescence creates additional challenges as DOTs consider the implications of CAV implementation. In anticipation of CAVs, state DOTs need to identify gaps in knowledge and skills and prepare for the challenges of CAV implementation while maintaining the existing roadway system at an acceptable level of service. Under NCHRP Project 14-42, Iowa State University was asked to estimate the impact of dynamic CAV technologies on roadway and TSMO asset maintenance programs. Among the findings, state DOTs are in the early stages of CAV technology implementation and lack significant experience with CAV asset maintenance. Additionally, many technologies have not been available for a sufficient amount of time, and as a result, the maintenance needs in many cases are unknown. Training and maintaining a skilled workforce is also challenging. Conse- quently, in many cases, state DOTs are temporarily contracting related work to third parties and piloting emerging technologies through public-private partnerships (PPP). CAVs will potentially lead to greater interconnectivity between systems, requiring additional skills and maintenance. In particular, significant changes are likely for pavement markings, roadside units, and vehicle-based on-board units as well as ITS and TSMO programs. A systems engineering approach will be beneficial for state DOTs as they consider resource allocation, system interoperability, and the potential for high-risk sudden failure of CAV technology once implemented. Additional research is needed to develop guidance on proposed standards associated with roadway and TSMO asset maintenance for preventive, reactive, and emerging maintenance needs. NCHRP Research Report 1084 provides a preliminary look at the state of practice related to CAV implementation and influencing factors for state DOT consideration. Additional deliverables, derived from NCHRP 14-42, are anticipated in the first quarter of 2024. F O R E W O R D By Camille Crichton-Sumners Staff Officer Transportation Research Board 16818-00b_FM-3rdPgs.indd 5 2/26/24 11:13 AM

1 Summary 3 Chapter 1 Introduction 3 1.1 Background 3 1.2 Project Objectives 4 1.3 CAV Technologies 5 1.4 Likely Scenarios and Expected Timeline for CAV Implementation 7 1.5 Summary of Findings 7 1.6 Overview of Report 8 Chapter 2 Information Gathering 8 2.1 Description of Literature Review 9 2.2 Description of Survey 9 2.3 Agency Interviews 10 2.4 Selection of Assets for Further Evaluation 11 2.5 Vendor Interviews 12 2.6 Summary of Information Gathering and General Insights 14 Chapter 3 Survey of Agencies 15 3.1 Most Current Changes to Physical Assets 18 3.2 Changes to Physical Infrastructure in the Next 3 Years 22 3.3 Changes in Asset Data Collection to Create Digital Infrastructure 24 3.4 Changes in Existing Maintenance Practices to Accommodate CAVs 25 3.5 Examples of Successful Maintenance Practices to Support CAVs 25 3.6 Additional Lessons Learned About Asset Maintenance for CAVs 26 3.7 Impact of CAV Maintenance Activities on Workforce Needs 27 3.8 Impact of CAVs on Other Maintenance Needs 27 3.9 Concerns About Other Aspects of Maintenance Related to CAV Activities 27 3.10 General Concerns Regarding CAV Activities Related to Maintenance 28 3.11 Summary of Survey 29 Chapter 4 RSUs for CV Applications 29 4.1 Description of RSUs 30 4.2 Gathering Maintenance Information for RSUs 30 4.3 Examples of Applications for RSUs 36 4.4 RSU Maintenance Needs 41 4.5 Standards, Guidelines, or Best Practices for Maintenance of RSUs 42 4.6 Summary of Workforce Needs to Address RSU Maintenance 43 Chapter 5 OBUs for CV Applications 43 5.1 Description of OBUs 43 5.2 Gathering Maintenance Information for OBUs 43 5.3 Examples of Applications for OBUs C O N T E N T S

46 5.4 Maintenance Needs for OBUs 46 5.5 Standards, Guidelines, or Best Practices for Maintenance of OBUs 46 5.6 Workforce Needs to Address Maintenance of OBUs 47 5.7 Summary of Maintenance Needs for OBUs 48 Chapter 6 Pavement Markings for AV Applications 48 6.1 Overview of Pavement Markings for AV Applications 49 6.2 Pavement Marking Standards for AVs 51 6.3 Potential Impacts of Enhancements to Pavement Marking Standards 51 6.4 Examples of Agency Activities to Enhance Pavement Marking Practices 54 6.5 Increased Maintenance Needs for Pavement Markings to Accommodate AVs as Reported by State DOTs 56 6.6 Standards, Guidelines, or Best Practices for Maintenance of Pavement Markings for AV Applications 56 6.7 Workforce Needs for Maintenance of Pavement Markings for AVs 57 6.8 Summary of Maintenance Information for Pavement Markings for AVs 58 Chapter 7 Infrastructure-Based Cameras for CAV Applications 58 7.1 Description of Infrastructure-Based Cameras 58 7.2 Gathering Maintenance Information for Camera Uses Specific to CAVs 58 7.3 General Camera Applications for CAVs 59 7.4 Description of Camera-Based Pedestrian and Bicyclist Detection Systems 60 7.5 Examples of Application of Pedestrian and Bicyclist Detection Systems 62 7.6 Maintenance Needs for Cameras for Pedestrian and Bicyclist Detection Applications 63 7.7 Standards, Guidelines, or Best Practices for Maintenance of Cameras Used in Pedestrian and Bicyclist Systems 63 7.8 Workforce Needs to Address Camera Maintenance Specific to CAV Applications 63 7.9 Summary of Maintenance Needs for Video-Detection Cameras 64 Chapter 8 Sign Maintenance for AV Applications 64 8.1 Description of Signing 64 8.2 Gathering Maintenance Information for Signing for AV Applications 65 8.3 Examples of Signing Applications for AVs 65 8.4 Maintenance Needs for Signs Specific to AVs 65 8.5 Standards, Guidelines, or Best Practices for Use and Maintenance of Signs Specific to AVs 67 8.6 Workforce Needs for Maintenance of Signs Specific to AVs 68 8.7 Summary of Maintenance Needs for Signs Specific to AVs 69 Chapter 9 Traffic Signal Controllers for CAV Applications 69 9.1 Description of Traffic Signal Controllers 70 9.2 Gathering Maintenance Information for Traffic Signals for CAVs 70 9.3 Examples of Applications of Traffic Signals for CAVs 71 9.4 Maintenance Needs for Traffic Signals for CAVs 72 9.5 Standards, Guidelines, or Best Practices for Application and Maintenance of Traffic Signals for CAVs 73 9.6 Workforce Needs for Maintenance of Traffic Signals for CAVs 73 9.7 Summary of Maintenance Needs for Traffic Signals for CAVs

74 Chapter 10 RWISs for CV Applications 74 10.1 Description of RWISs for CV Applications 75 10.2 Gathering Maintenance Information for RWISs 75 10.3 Examples of CV Applications for RWISs 76 10.4 Maintenance Needs for RWISs 77 10.5 Standards, Guidelines, or Best Practices for Maintenance of RWISs for CVs 78 10.6 Workforce Needs for Maintenance of RWISs for CVs 78 10.7 Summary of Maintenance Needs for RWISs 79 Chapter 11 Additional Communication Capacity for CV Applications 79 11.1 Description of Additional Communication Capacity for CVs 79 11.2 Gathering Maintenance Information for Additional Communication Capacity Specific to CVs 79 11.3 Examples of Applications of Additional Communication Capacity for CVs 81 11.4 Maintenance Needs for Additional Communication Capacity Specific to CVs 81 11.5 Standards, Guidelines, or Best Practices for Maintenance of Communication Capacity for CVs 81 11.6 Workforce Needs for Maintenance of Communication Capacity for CVs 81 11.7 Summary of Maintenance Needs for Communication Capacity for CVs 82 Chapter 12 Machine-Readable Signs for AVs 82 12.1 Description of Machine-Readable Signs 82 12.2 Gathering Information for Maintenance of Machine-Readable Signs for AVs 82 12.3 Examples of Machine-Readable Signs for AV Applications 83 12.4 Maintenance and Workforce Needs for Maintenance of Machine-Readable Signs for AVs 83 12.5 Summary of Maintenance Needs for Machine-Readable Signs for AVs 84 Chapter 13 Data and Digital Infrastructure for CAV Applications 84 13.1 Description of Digital Infrastructure for CAV-Related Assets 84 13.2 Gathering Information for Digital Infrastructure for CAV-Related Assets 84 13.3 Examples of Applications of Digital Infrastructure for CAV-Related Assets 86 13.4 Summary of Maintenance and Workforce Needs for Digital Infrastructure for CAVs 87 Chapter 14 Resource Gaps 87 14.1 Background/Setting the Stage 90 14.2 CAV Resource Planning Process 93 14.3 Systems Engineering 95 14.4 Return on Investment 96 14.5 Procuring with Maintenance in Mind 96 14.6 Field Device Installation and Operations 97 14.7 Back-Office Operations 99 14.8 Fleet Operations 100 14.9 Maintenance 102 14.10 End of Life Cycle and Replacement 103 14.11 Summary of the Impact of CAVs on Resource Gaps

105 Chapter 15 CAV Workforce Implications 106 15.1 Review of CAV Workforce Literature 111 15.2 One-on-One Agency Interview Findings 113 15.3 Insights from Maintenance Contractor Interviews 113 15.4 Key Themes and Suggestions 115 Chapter 16 Summary and Implementation 115 16.1 Summary 116 16.2 Suggestions for Implementation 118 References 123 Abbreviations, Acronyms, and Initialisms A-1 Appendix Additional Comments from Survey 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 nap.nationalacademies.org) retains the color versions.