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BTSCRP Web-Only Document 1 Influence of Infrastructure Design on Distracted Driving Shauna Hallmark Nicole Oneyear John Shaw Institute for Transportation Iowa State University Ames, Iowa John Gaspar Cher Carney Chris Schwarz University of Iowa Iowa City, Iowa Conduct of Research Report for BTSCRP Project BTS-09 Submitted November 2021 ACKNOWLEDGMENT This work was sponsored by the Governors Highway Safety Association (GHSA) and funded by the National Highway Traffic Safety Administration (NHTSA). It was conducted through the Behavioral Traffic Safety Cooperative Research Program (BTSCRP), which is administered by the Transportation Research Board (TRB), part of the National Academies of Sciences, Engineering, and Medicine. 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, FTA, GHSA, NHTSA, 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. DISCLAIMER The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research. They are not necessarily those of the Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; or the program sponsors. The information contained in this document was taken directly from the submission of the author(s). This material has not been edited by TRB.
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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 BTSCRP WEB-ONLY DOCUMENT 1 Christopher J. Hedges, Director, Cooperative Research Programs Lori L. Sundstrom, Deputy Director, Cooperative Research Programs Richard Retting, Senior Program Officer Natalie Barnes, Director of Publications Heather DiAngelis, Associate Director of Publications Jennifer Correro, Assistant Editor BTSCRP PROJECT BTS-09 PANEL Ronald L. Johnston, J Lee Milligan, Amarillo, TX (Chair) Osama A. Abaza, University of Alaska, Anchorage, Anchorage, AK Noah Budnick, Zendrive Inc., San Francisco, CA Robert E. Dewar, Western Ergonomics, Inc., Calgary, AB Nick Ferenchak, University of New Mexico, Albuquerque, NM Robert Kearney, Massachusetts Department of Transportation, Boston, MA Maria E. Vegega, Road Safety Consulting, Alexandria, VA Jerry Wachtel, The Veridian Group, Inc., Berkeley, CA Jordan Blenner, National Highway Traffic Safety Administration (NHTSA) Liaison AUTHOR ACKNOWLEDGMENTS The research reported herein was performed under Behavioral Traffic Safety Cooperative Research Program (BTSCRP) Project BTS-09 by the Center for Transportation Research and Education (CTRE) at Iowa State University (ISU). ISU was the contractor for this study, with the University of Iowa (UI) serving as a subcontractor. The authors would like to acknowledge the many individuals and organizations that made this research project possible. In particular, thanks are due to William Rogers and Richard Retting, Senior Program Officers for the BTSCRP, for all of their assistance. The authors would also like to thank the BTS-09 panel for their insight and service.
F O R E W O R D By Richard Retting Staff Officer Transportation Research Board BTSCRP Web-Only Document 1: Influence of Infrastructure Design on Distracted Driving presents the results of a systematic review of information about the relationships between distraction and specific infrastructure elements. Researchers identified sources of existing public and private data that could be used to develop safety frameworks to evaluate the association between distracted driving and roadway or roadside infrastructure and developed a set of five conceptual safety frameworks. Distracted driving is a prevalent, complex, and growing traffic safety issue. Whether due to habitual behaviors or immediate deliberate decision-making, many drivers engage in risky behaviors that shift their attention and focus away from the primary task of driving, increasing the likelihood of crashes. The National Highway Traffic Safety Administration estimates distracted driving claimed more than 3,000 lives in 2019. In addition to in-vehicle sources of driver distraction, the occurrence of distracted driving behaviors can be influenced by features of the driving environment, such as distinctive built structures. It would be useful to determine the relationships between the presence, absence, location, or design of different types of built structures and the occurrence of distracted driving. In BTSCRP Project BTS-09, Iowa State University was asked to (1) review existing information about the relationships between distraction and specific infrastructure elements; (2) identify sources of existing public and private data that could be used in the development of safety frameworks for evaluating the association between distracted driver behaviors and roadway and roadside infrastructure; and (3) develop and test a conceptual safety framework The safety frameworks are intended as templates to guide agencies and other stakeholders in using a particular data source to assess the distraction potential of a specific infrastructure element.
v Table of Contents List of Figures ............................................................................................................................... vii List of Tables ................................................................................................................................ viii Summary ......................................................................................................................................... 1 Chapter 1. Introduction ................................................................................................................... 2 1.1 Background ......................................................................................................................... 2 1.2 Objectives ........................................................................................................................... 2 1.3 Overview of Report ............................................................................................................. 3 1.4 Common Definitions ........................................................................................................... 4 1.5 Summary ............................................................................................................................. 6 Chapter 2. Distraction as It Relates to Infrastructure Elements ...................................................... 7 2.1 General Definition of Distraction ....................................................................................... 7 2.2 Identifying Driver Distraction in Crash Forms ................................................................... 9 2.3 Driver Distraction from the Perspective of Infrastructure Elements ................................ 11 2.4 Summary ........................................................................................................................... 16 Chapter 3. Summary of Known Relationships Between Infrastructure Elements and Distraction ............................................................................................................................... 17 3.1 Outside-the-Vehicle Distractions ...................................................................................... 17 3.2 Billboards and Outdoor Advertising ................................................................................. 19 3.3 Smaller Advertising Signs ................................................................................................ 21 3.4 Traffic Signs ...................................................................................................................... 22 3.5. Urban Clutter ................................................................................................................... 22 3.6 Wind Turbines .................................................................................................................. 24 3.7. Railroad Crossings ........................................................................................................... 27 3.8 Pavement Condition .......................................................................................................... 27 3.9 Geometric Features ........................................................................................................... 28 3.10 General Infrastructure ..................................................................................................... 28 3.11 Discussion ....................................................................................................................... 29 Chapter 4. Sources of Data for the Development of Safety Frameworks ..................................... 32 4.1 Naturalistic Driving Studies .............................................................................................. 32 4.2 Simulator Data Sets........................................................................................................... 40 4.3 Crash Data ......................................................................................................................... 43 4.4 Roadway and Infrastructure Inventories ........................................................................... 48 Chapter 5. Safety Frameworks ...................................................................................................... 58 Chapter 6. Safety Framework for the Use of Crash Narratives to Assess the Impact of Infrastructure Design on Distraction ....................................................................................... 59 6.1 Introduction ....................................................................................................................... 59 6.2 Data Sets Utilized ............................................................................................................. 61 6.3 Data Request and Data Reduction .................................................................................... 61
vi 6.4 Analysis............................................................................................................................. 63 6.5 Outcomes and Discussion ................................................................................................. 67 Chapter 7. Safety Framework for the Use of Crash Data to Assess the Impact of Infrastructure Design on Distraction ....................................................................................... 70 7.1 Introduction ....................................................................................................................... 70 7.2 Data Sets Utilized ............................................................................................................. 72 7.3 Data Reduction.................................................................................................................. 74 7.4 Analysis of Segments in the Vicinity of Wind Turbines .................................................. 75 7.5 Analysis of OVD Crashes ................................................................................................. 78 7.6 Outcomes and Discussion ................................................................................................. 78 Chapter 8. Safety Framework to Assess the Impact of Railroad Crossings on Distraction Using the SHRP2 NDS Data................................................................................................... 82 8.1 Introduction ....................................................................................................................... 82 8.2 Data Sets Utilized ............................................................................................................. 83 8.3 Data Request and Data Reduction .................................................................................... 85 8.4 Analysis............................................................................................................................. 87 8.5 Outcomes and Discussion ................................................................................................. 90 Chapter 9. Safety Framework to Assess the Impact of Overhead Dynamic Message Signs on Distraction Using the SHRP2 NDS Data ........................................................................... 96 9.1 Introduction ....................................................................................................................... 96 9.2 Data Sets Utilized ............................................................................................................. 97 9.3 Data Request and Data Reduction .................................................................................... 99 9.4 Analysis........................................................................................................................... 100 9.5 Outcomes and Discussion ............................................................................................... 105 Chapter 10. Safety Framework to Assess the Impact of Highway Signs on Distraction Using Simulator Data ............................................................................................................ 110 10.1 Introduction ................................................................................................................... 110 10.2 Data Sets Utilized ......................................................................................................... 111 10.3 Analysis......................................................................................................................... 115 10.4 Modeling Approach and Results ................................................................................... 116 10.5 Outcomes and Discussion ............................................................................................. 121 Chapter 11. Conclusions and Recommendations ........................................................................ 125 11.1 Summary ....................................................................................................................... 125 11.2 Key Findings and Recommendations ........................................................................... 126 11.3 Future Research Needs ................................................................................................. 132 References ................................................................................................................................... 134 Abbreviations, Acronyms, and Initialisms .................................................................................. 142
vii List of Figures Figure 1. Odds ratios for eyes-off-road glances in windows within 12 seconds surrounding a crash. ...................................................................................................................................... 9 Figure 2. Commuter rail station adjacent to the Attica Tollway in Athens, Greece. ..................... 13 Figure 3. Billboard with scrolling text. ......................................................................................... 20 Figure 4. Visual clutter in Breezewood, Pennsylvania (2006). ..................................................... 23 Figure 5. Wind turbines along a canal in the Netherlands. ........................................................... 26 Figure 6. Scenes from University of Iowa simulator data sets. .................................................... 42 Figure 7. Geographical distribution of CRSS data collection sites. ............................................. 46 Figure 8. Business signing. ........................................................................................................... 52 Figure 9. Building advertising. ..................................................................................................... 52 Figure 10. Location and height of buildings in Washington, DC. ................................................ 53 Figure 11. Example image from Google Street View. .................................................................. 56 Figure 12. Older imagery from Google Street View (April 2009 view of an intersection in Kokomo, Mississippi, retrieved in February 2020). ............................................................... 57 Figure 13. Michigan Traffic Crash Fact portal. ............................................................................ 61 Figure 14. Summary of crash narrative coding results. ................................................................ 66 Figure 15. Word cloud created for crashes coded as involving an OVD but not IRD. ................. 67 Figure 16. Wind turbines along a two-lane roadway in Iowa. ...................................................... 71 Figure 17. Wind turbines (red dots) and 2019 crashes (blue dots) in Iowa. ................................. 74 Figure 18. Forward video view at a railroad crossing. ................................................................. 84 Figure 19. Railroad crossing in Google Street View. .................................................................... 85 Figure 20. Location of train tracks noted as vehicle crossing at timestamp #51776. ................... 86 Figure 21. Proportion of time drivers are glancing at the forward (top) or left/right (bottom) areas of the windshield............................................................................................................ 89 Figure 22. Typical overhead DMS. ............................................................................................... 96 Figure 23. Percentage of time drivers spent glancing forward when sign was on (right) or off (left). ................................................................................................................................ 102 Figure 24. NADS-1 driving simulator (left); cab view inside NADS-1 during a nighttime driving scenario (right). ......................................................................................................... 111 Figure 25. Face Lab 5.0 cameras mounted in the cab, with a separate head tracking system mounted between them. ........................................................................................................ 112 Figure 26. Map of the urban, Interstate, and rural drive segments in the simulator study. ......... 113
viii Figure 27. Examples of two billboards (top), a route sign (middle left), an overhead sign (middle right), an overpass sign (bottom left), and a route sign for an exit (bottom right). ..................................................................................................................................... 114 Figure 28. Potential features of interest along the urban roadway segment. .............................. 115 Figure 29. Number of glances to different external features. ..................................................... 117 Figure 30. Average glance time across the external features, with points representing individual drivers. ................................................................................................................. 118 Figure 31. Total glance time across the external events, with points representing individual drivers. .................................................................................................................................. 118 Figure 32. Horizontal gaze dispersion for the overhead sign before the bypass event. .............. 120 Figure 33. PRC gaze for the route sign before the exit event. .................................................... 121 List of Tables Table 1. Taxonomy of visual information distractions. ................................................................ 12 Table 2. Fixation percentage and duration for various types of advertising. ................................ 22 Table 3. Average glance durations for roadway and roadside elements. ...................................... 28 Table 4. Summary of naturalistic driving study data sets. ............................................................ 34 Table 5. Summary of crash data sets. ............................................................................................ 43 Table 6. Summary of roadway and infrastructure data sets. ......................................................... 49 Table 7. Crash narratives coded as involving an OVD. ................................................................ 62 Table 8. Parameter estimates of wind turbines crash model. ........................................................ 77 Table 9. Comparison of OVD crashes near wind turbines. ........................................................... 78 Table 10. Percentage of time looking forward within DMS influence area. .............................. 103 Table 11. Standard deviation of speed within DMS influence area. ........................................... 105 Table 12. Simulator study demographics. ................................................................................... 112 Table 13. External roadway features included in analysis. ......................................................... 114 Table 14. Results (p-values) of Ï2 tests comparing models with and without epoch. ................. 119
