Site-Based Video System Design and Development (2012)

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TRANSPORTATION RESEARCH BOARD WASHINGTON, D.C. 2012 www.TRB.org 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 REPORT S2-S09-RW-1 Site-Based Video System Design and Development TimoThy Gordon University of Michigan Zevi BarekeT, Lidia kosTyniuk, micheLLe Barnes, and michaeL haGan University of Michigan Transportation Research Institute Zu kim, deLphine cody, and aLexander skaBardonis California PATH aLan vayda Soar Technology

Subscriber Categories Design Highways Operations and Traffic Management Safety and Human Factors

SHRP 2 Reports Available by subscription and through the TRB online bookstore: www.TRB.org/bookstore Contact the TRB Business Office: 202-334-3213 More information about SHRP 2: www.TRB.org/SHRP2 SHRP 2 Report S2-S09-RW-1 ISBN: 978-0-309-12924-4 © 2012 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. Per- mission is given with the understanding that none of the material will be used to imply TRB, AASHTO, or FHWA endorsement of a particular product, 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 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 technologies, and human factors science—offer a new oppor- tunity to improve the safety and reliability of this important national resource. Breakthrough resolution of significant trans- portation 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 Stra- tegic Highway Research Program, is a focused, time-constrained, management-driven program designed to complement exist- ing 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 pro- duce 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 transportation 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 memorandum of understanding among the American Associa- tion 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.

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. Charles M. Vest 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. Harvey V. Fineberg 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. Charles M. Vest 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 Walter Diewald, Senior Program Officer for SHRP 2 Safety. The research reported on herein was performed by the University of Michigan Transportation Research Institute (UMTRI) in collaboration with California PATH and Soar Technology. Timothy Gordon was the project director and principal investigator. The authors acknowledge technical and logistical support from the Washtenaw County Road Commission, which owns and manages the intersection used in this study. The authors are grateful to the road commission for its help and support throughout this project. SHRP 2 STAFF Ann M. Brach, Director Stephen J. Andrle, Deputy Director Neil J. Pedersen, Deputy Director, Implementation and Communications Kizzy Anderson, Senior Program Assistant, Implementation James Bryant, Senior Program Officer, Renewal Kenneth Campbell, Chief Program Officer, Safety JoAnn Coleman, Senior Program Assistant, Capacity and Reliability Eduardo Cusicanqui, Finance Officer Walter Diewald, Senior Program Officer, Safety Jerry DiMaggio, Implementation Coordinator Charles Fay, Senior Program Officer, Safety Carol Ford, Senior Program Assistant, Renewal and Safety Elizabeth Forney, Assistant Editor Jo Allen Gause, Senior Program Officer, Capacity Abdelmename Hedhli, Visiting Professional 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 Michael Marazzi, Senior Editorial Assistant Linda Mason, Communications Officer Reena Mathews, Senior Program Officer, Capacity and Reliability Matthew Miller, Program Officer, Capacity and Reliability Michael Miller, Senior Program Assistant, Capacity and Reliability David Plazak, Senior Program Officer, Capacity Monica Starnes, Senior Program Officer, Renewal Charles Taylor, Special Consultant, Renewal Onno Tool, Visiting Professional Dean Trackman, Managing Editor Pat Williams, Administrative Assistant Connie Woldu, Administrative Coordinator Patrick Zelinski, Communications Specialist

The goal of the SHRP 2 Safety program is to prevent or reduce the severity of highway crashes through more accurate knowledge of driver behavior and other factors. The Safety program’s research is proceeding along two distinct but related tracks: (1) the in-vehicle, naturalistic driving study, which encompasses all types of driving, and (2) the site-based risk study, which focuses on vehicle trajectories at specific locations, such as intersections. This report describes the work that was done in the latter track to develop and test an on-site, video- based data collection system with the potential for widespread application by researchers and state and local authorities to examine intersection safety. This report documents the development of a prototype system capable of capturing vehicle movements through intersections by using a site-based video imaging system. By tracking individual vehicles through an intersection, the Site Observer provides a basis not only for viewing crashes and near crashes but also for developing objective measures of intersection conflicts and collecting before-and-after data when design or operational changes are made at intersections. It also yields detailed and searchable data on the normal driving population so that exposure measures can be determined. This research built on previous work on video-based systems to develop a system that is relatively inexpensive, portable, and flexible enough for installation at all types of inter- sections, as well as robust enough for use in locations with a wide range of environmental conditions. The system embraces modern machine vision cameras and draws from the large body of research on algorithms for extracting information from video streams, a key advan- tage where data must be collected continuously. It was tested at a location during fall and winter months and found to operate as designed. The Site Observer is a robust prototype system that is deployable as is but is also capable of further development and refinement for use in intersection safety assessment. F O R EWO R D Walter Diewald, PhD, SHRP 2 Senior Program Officer, Safety

C O N T E N T S 1 Executive Summary 5 CHAPTER 1 Introduction 8 CHAPTER 2 Safety Research Questions 8 Intersection Safety 9 Research Questions for Intersection Safety 11 Road Departure Safety 14 CHAPTER 3 Existing Video-Based Vehicle Monitoring Systems 14 Commercial Systems 16 Research-Based Systems 19 Object Tracking Research 21 CHAPTER 4 Performance Requirements 22 Trajectory Information 22 Vehicle Information 22 Data Availability 23 Error Checking and Estimation 23 Computational Aspects and Streaming Capability 24 User Interface 25 CHAPTER 5 Conflict Metrics and Crash Surrogates 25 Intersection-Related Conflict Metrics 29 Accuracy Requirements from Conflict Metric Analysis 36 CHAPTER 6 Site Observer Design 36 Design Concept 38 System Design 41 CHAPTER 7 System Hardware and Site Installation 41 Choice of Intersection 44 Hardware and Site Installation 50 CHAPTER 8 Image Processing and Feature Extraction 50 Background Subtraction 50 Clusters and Cluster Tracking 52 Feature Extraction and Data Representation 54 Effects of Environmental Conditions 56 CHAPTER 9 Vehicle Localization and Trajectory Estimation 56 Multicamera Cluster Tracks 64 CHAPTER 10 Trajectory Refinement and Estimation of Motion Variables 64 Multicluster Centroid Path 64 Motion Estimation: Kalman Filtering

68 CHAPTER 11 Performance Evaluation 69 Positioning Accuracy 72 Speed and Acceleration Evaluation 75 CHAPTER 12 Conflict Analysis 75 Left Turn Across Path 75 Right Turn into Path 79 CHAPTER 13 Conclusions 81 Future Research 82 References