Naturalistic Driving Study: Descriptive Comparison of the Study Sample with National Data (2015)

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The Second S T R A T E G I C H I G H W A Y R E S E A R C H P R O G R A M TRANSPORTATION RESEARCH BOARD WASHINGTON, D.C. 2015 www.TRB.org REPORT S2-S31-RW-1 Naturalistic Driving Study: Descriptive Comparison of the Study Sample with National Data Jon Antin, Kelly Stulce, liSA eichelberger, And Jon hAnKey Virginia Tech Transportation Institute Blacksburg, Virginia

Subject Areas Data and Information Technology Highways Safety and Human Factors Vehicles and Equipment

The Second Strategic Highway Research Program America’s highway system is critical to meeting the mobility and economic needs of local communities, regions, and the nation. Developments in research and technology—such as advanced materials, communications technology, new data collection tech- nologies, and human factors science—offer a new opportunity to improve the safety and reliability of this important national resource. Breakthrough resolution of significant transportation problems, however, requires concentrated resources over a short time frame. Reflecting this need, the second Strategic Highway Research Program (SHRP 2) has an intense, large-scale focus, integrates multiple fields of research and technology, and is fundamentally different from the broad, mission-oriented, discipline-based research programs that have been the mainstay of the highway research industry for half a century. The need for SHRP 2 was identified in TRB Special Report 260: Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life, published in 2001 and based on a study sponsored by Congress through the Transportation Equity Act for the 21st Century (TEA-21). SHRP 2, modeled after the first Strategic Highway Research Program, is a focused, time- constrained, management-driven program designed to com- plement existing highway research programs. SHRP 2 focuses on applied research in four areas: Safety, to prevent or reduce the severity of highway crashes by understanding driver behavior; Renewal, to address the aging infrastructure through rapid design and construction methods that cause minimal disruptions and produce lasting facilities; Reliability, to reduce congestion through incident reduction, management, response, and mitigation; and Capacity, to integrate mobility, economic, environmental, and community needs in the planning and designing of new trans- portation capacity. SHRP 2 was authorized in August 2005 as part of the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU). The program is managed by the Transportation Research Board (TRB) on behalf of the National Research Council (NRC). SHRP 2 is conducted under a memo- randum of understanding among the American Association of State Highway and Transportation Officials (AASHTO), the Federal Highway Administration (FHWA), and the National Academy of Sciences, parent organization of TRB and NRC. The program provides for competitive, merit-based selection of research contractors; independent research project oversight; and dissemination of research results. SHRP 2 Reports Available by subscription and through the TRB online bookstore: www.mytrb.org/store Contact the TRB Business Office: 202-334-3213 More information about SHRP 2: www.TRB.org/SHRP2 SHRP 2 Report S2-S31-RW-1 ISBN: 978-0-309-31491-6 © 2015 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 copy- right to any previously published or copyrighted material used herein. The second Strategic Highway Research Program grants permission to repro- duce 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, or FHWA endorsement of a particular prod- uct, method, or practice. It is expected that those reproducing material in this document for educational and not-for-profit purposes will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from SHRP 2. Note: SHRP 2 report numbers convey the program, focus area, project number, and publication format. Report numbers ending in “w” are published as web documents only. Notice The project that is the subject of this report was a part of the second Strategic 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 committee 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 committee 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 second Strategic Highway Research Program do not endorse products or manufacturers. Trade or manufacturers’ 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 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 achieve- ments of engineers. Dr. C. D. (Dan) Mote, Jr., 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. Victor J. Dzau 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 Academy’s 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. C. D. (Dan) Mote, Jr., 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 Transportation Research Board is to provide leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisci- plinary, and multimodal. The Board’s 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 Transporta- tion, and other organizations and individuals interested in the development of transportation. www.TRB.org www.national-academies.org

ACKNOWLEDGMENTS This work was sponsored by the Federal Highway Administration in cooperation with the American Asso- ciation of State Highway and Transportation Officials. It was conducted in the second Strategic Highway Research Program (SHRP 2), which is administered by the Transportation Research Board of the National Academies. The project was managed by Kenneth L. Campbell, Chief Program Officer for SHRP 2 Safety. James H. Hedlund, SHRP 2 Consultant for Safety Coordination, also contributed to the project. The research reported in this document was performed by the Virginia Tech Transportation Institute (VTTI). The authors acknowledge the contributions of VTTI Director Thomas Dingus, who served as principal investigator, and Feng Guo and Jeremy Sudweeks of VTTI, who made valuable contributions to the early conceptualization and structuring of the analyses supporting this effort. SHRP 2 STAFF Ann M. Brach, Director Stephen J. Andrle, Deputy Director Cynthia Allen, Editor Kenneth Campbell, Chief Program Officer, Safety Jared Cazel, Editorial Assistant JoAnn Coleman, Senior Program Assistant, Capacity and Reliability Eduardo Cusicanqui, Financial Officer Richard Deering, Special Consultant, Safety Data Phase 1 Planning Shantia Douglas, Senior Financial Assistant Charles Fay, Senior Program Officer, Safety Carol Ford, Senior Program Assistant, Renewal and Safety James Hedlund, Special Consultant, Safety Coordination Alyssa Hernandez, Reports Coordinator Ralph Hessian, Special Consultant, Capacity and Reliability Andy Horosko, Special Consultant, Safety Field Data Collection William Hyman, Senior Program Officer, Reliability Linda Mason, Communications Officer David Plazak, Senior Program Officer, Capacity and Reliability Rachel Taylor, Senior Editorial Assistant Dean Trackman, Managing Editor Connie Woldu, Administrative Coordinator

This report provides a descriptive comparison of data from the SHRP 2 Naturalistic Driving Study (NDS) sample and national data. The primary objective of the SHRP 2 NDS is to sup- port analyses relating crash risk to driver, vehicle, roadway, and environmental characteristics. Since age is one of the most important driver characteristics, this objective is best supported by adequate sample sizes across all age groups. The national population of drivers has the greatest number of drivers in the middle age groups and progressively fewer in the younger and older ages. In contrast, the NDS oversampled younger and older drivers. In addition, the NDS oversampled newer-model-year vehicles because these vehicles provided useful data through their vehicle networks. It is important for users of the NDS data to have information on the relationship of the NDS sample to the national population. In general, many statistics taken directly from the NDS sample will not be nationally representative unless they are adjusted to account for relevant characteristics of the NDS sample. The SHRP 2 NDS is the first large-scale study focused on collision prevention (as opposed to injury prevention once a collision occurs) since the Indiana Tri-Level Study (Tri-Level Study of the Causes of Traffic Accidents: Final Report, Report DOT HS-805 085, U.S. Department of Transportation, May 1979). Vehicle use was recorded continuously in the SHRP 2 NDS. Infor- mation on vehicle travel, or exposure, can be extracted at the same level of detail as for safety- related events like crashes and near crashes. Hence, the SHRP 2 NDS is the first large-scale study to support detailed estimates of collision risk. Moreover, crashes are a leading cause of nonrecurring congestion. Collision prevention has added benefits in terms of reduced delay, fuel consumption, and emissions. The focus of the NDS is to provide objective information on the role of driver behavior and performance in traffic collisions and the interrelationship of the driver with vehicle, roadway, and environmental factors. The SHRP 2 Safety research program was carried out under the guidance of the Safety Tech- nical Coordinating Committee (TCC), which was composed of volunteer experts. The Safety TCC developed and approved all project descriptions and budgets and met semiannually to review progress and approve any program modifications. The Oversight Committee approved all budget allocations and contract awards. Assistance was provided by expert task groups, which developed requests for proposals, evaluated proposals and recommended contractors, and provided expert guidance on many issues, such as data access policies and procedures. The decisions and recommendations of the governing committees were implemented by SHRP 2 staff as they carried out day-to-day management of the research projects. F O R EWO R D Kenneth L. Campbell, SHRP 2 Chief Program Officer, Safety

C O N T E N T S 1 Executive Summary 2 CHAPTER 1 Introduction 2 Representativeness 3 Goal of This Report 3 Approach 4 CHAPTER 2 Data Collection Site Selection 4 Data Collection Site Comparisons 12 CHAPTER 3 Participant Sample Design and Operations 12 Participant Recruitment and Screening 16 CHAPTER 4 Data Comparisons 16 Participant Characteristics 16 Socioeconomic Factors 22 Vehicle Fleet Composition 24 Crash Rates 29 CHAPTER 5 Summary and Conclusion 29 How Do the Selected Sites in Aggregate Compare to the United States as a Whole? 29 How Do the Participants Sampled Compare to All Drivers in the United States? 29 How Do the Vehicles Sampled Compare to the Entire U.S. Fleet? 30 How Do Police-Reported Crash Rates Observed in the Study Compare to Crash Rates in the United States as a Whole? 30 Conclusion 31 References 33 Appendix A. Weighting Factors