Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
NCHRP Web-Only Document 273: Road User Understanding of Bicycle Signal Faces on Traffic Signals Christopher Monsere Christina Fink Sirisha Kothuri Bill Schultheiss Portland State University Thomas Hillman Portland, Oregon Gwen Shaw Jesse Boudart David Hurwitz Toole Design Group, Inc. Douglas Cobb Silver Spring, Maryland Oregon State University Corvallis, Oregon Final Report for NCHRP Project 20-07/Task 420 Submitted November 2019 ACKNOWLEDGMENT This work was sponsored by the American Association of State Highway and Transportation Officials (AASHTO), in cooperation with the Federal Highway Administration, and was conducted in the National Cooperative Highway Research Program (NCHRP), which is administered by the Transportation Research Board (TRB) 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, 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. 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.
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 provide leadership in transportation improvements and innovation through trusted, timely, impartial, and evidence-based information exchange, research, and advice regarding all modes of transportation. The Boardâs varied activities annually engage about 8,000 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.
COOPERATI VE RESEAR CH PROGRAMS CRP STAFF FOR NCHRP Web-Only Document 273 Christoper J. Hedges, Director, Cooperative Research Programs Lori L. Sundstrom, Deputy Director, Cooperative Research Programs Ann M. Hartell, Senior Program Officer Jarrel McAfee, Senior Program Assistant Eileen P. Delaney, Director of Publications Natalie Barnes, Associate Director of Publications Jennifer Correro, Assistant Editor NCHRP PROJECT 20-07/Task 420 PANEL AREA OF SPECIAL PROJECTS Alexander Kevin Barr, Florida DOT, Fort Lauderdale, FL Drew L. Buckner, Michigan DOT, Chesterfield, MI Julius A. Codjoe, Louisiana DOTD, Baton Rouge, LA Naa-Atswei Tetteh, Delaware DOT, Smyma, DE Gabriel Thum, Pima Association of Governments, Tucson, AZ Ivan B. Ulberg, Montana DOT, Helena, MT Ann H. Do, FHWA Liaison ACKNOWLEDGMENTS The research reported herein was performed under NCHRP 20-07 Task 420. Dr. Christopher M. Monsere, P.E., Professor of Civil and Environmental Engineering at Portland State University PSU, was the Principal Investigator. The other authors of this report are Dr. Sirisha Kothuri, (PSU), Dr. David Hurwitz, Oregon State University (OSU), Douglas Cobb, OSU, Christina Fink, Toole Design Group, Inc. (TDG), Bill Schultheiss, TDG, Jesse Boudart, TDG, Thomas Hillman, TDG, and Gwen Shaw, TDG. A number of students contributed to the data collection effort including Duong Vu at Portland State University and Alden Sova, Logan Scott-Deeter, Jason Formanack, and Lukas Bauer at Oregon State University. Hagai Tapiro, postdoctoral researcher at Oregon State University, contributed to the literature review. The agency staff who participated in the interview provided valuable insight and shared their experience. Rock Miller was instrumental in developing the list of intersections for inventory as he shared the initial NCUTCD list he had compiled. In addition, the research team acknowledges the people who responded to our survey to identify intersections with bicycle signals.
TABLE OF CONTENTS SUMMARY ................................................................................................................................................. 1 INTRODUCTION....................................................................................................................................... 4 Project Objectives ..................................................................................................................................... 5 Overview of Project by Tasks ................................................................................................................... 5 Purpose and Organization of Report ......................................................................................................... 6 BACKGROUND AND LITERATURE REVIEW ................................................................................... 7 Basic Human Factors Concepts ................................................................................................................ 7 Visibility and Comprehension of Bicycle Signal Face ........................................................................... 12 Compliance ............................................................................................................................................. 16 Safety at Intersections with Bicycle Signals ........................................................................................... 20 Related Traffic Control Devices ............................................................................................................. 21 Summary ................................................................................................................................................. 24 STATE OF THE PRACTICE AND INVENTORY ............................................................................... 26 Design Guidance ..................................................................................................................................... 26 Inventory of Intersections with Bicycle Signals ..................................................................................... 28 Summary ................................................................................................................................................. 46 KEY AGENCY INTERVIEWS ............................................................................................................... 49 Methodology and Recruitment................................................................................................................ 49 Interview Results .................................................................................................................................... 50 Summary ................................................................................................................................................. 67 IDENTIFIED RESEARCH GAPS .......................................................................................................... 68 Optimal Methods to Communicate Allowable, Protected, or Permissive Movements to Bicyclists at Signalized Intersections .......................................................................................................................... 68 Evaluation of Size, Placement, and Orientation of Bicycle Signal Faces on Bicyclist and Driver Comprehension and Compliance ............................................................................................................ 69 Guidance on Visibility and Detection of Bicycle Symbols in Signal Faces by Lens Size and Distance 70 REFERENCES .......................................................................................................................................... 71 ACRONYMS ............................................................................................................................................. 80 APPENDIX A â LIST OF INTERSECTIONS..................................................................................... A-1 APPENDIX B â DATA COLLECTION PROTOCOL ....................................................................... B-1 APPENDIX C â RESEARCH NEEDS STATEMENTS ..................................................................... C-1
List of Tables Table 1. Intersections with Bicycle Signal Faces by State and Jurisdiction ............................................... 30 Table 2. Summary of Typical Applications of Bicycle Signals .................................................................. 34 Table 3. Number of Intersections by Phasing Type .................................................................................... 41 Table 4. Number of Approaches by Bicycle and Vehicular Signal Heads ................................................. 42 Table 5. Number of Approaches by Visibility Distance, Lens Size, and Bicycle Signal Heads ................ 43 Table 6. Number of Approaches by Placement of Bicycle Signal and Mounting ...................................... 44 Table 7. Horizontal and Vertical Placement of Bicycle Signal Face from Nearest Motor Vehicle Face ... 45 Table 8. Summary of Inventory of Bicycle Symbol in the Signal Face...................................................... 47 Table 9. Summary of Interviewed Agencies ............................................................................................... 50 Table 10. Respondents Involvement in Bicycle Signals ............................................................................. 50 Table 11. Public Comments, Driver Confusion .......................................................................................... 51 Table 12. Public Comments, Persons on Bicycle Confusion ...................................................................... 52 Table 13. Experience with Bicycle/Motor Vehicle Crashes ....................................................................... 53 Table 14. Public Education Efforts ............................................................................................................. 53 Table 15. Is Research Needed, Distance Symbol Face Visible .................................................................. 54 Table 16. Research Needed, Improved Conspicuity of Symbol Face ......................................................... 55 Table 17. Research Needed, Selection of Lens Size ................................................................................... 55 Table 18. Use of Visibility-Restriction Devices ......................................................................................... 56 Table 19. Use of Near-side Four-Inch Bicycle Signal Faces ...................................................................... 56 Table 20. Guidance Used for Placement of Signal Faces ........................................................................... 57 Table 21. Guidance Used for Signal Placement.......................................................................................... 57 Table 22. Study of Compliance Based on Placement ................................................................................. 58 Table 23. Design Constraints for Placing Bicycle Signal ........................................................................... 58 Table 24. Challenges with Installing the R10-10b âBicycle Signalâ Sign.................................................. 59 Table 25. R10-10b Sign Beneficial ............................................................................................................. 59 Table 26. Use of Color or Backplate to Distinguish Bicycle Signal ........................................................... 60 Table 27. Research Needed, Differentiate Bicycle Signals ........................................................................ 61 Table 28. IA-16 Impacted Installation of Bicycle Signal Faces ................................................................. 61 Table 29. Vehicle Movements Restricted During Bicycle Green ............................................................... 62 Table 30. Type of Vehicle Movements Restricted...................................................................................... 62 Table 31. Duration of Phase Vehicle Movements Restricted ..................................................................... 62 Table 32. Methods for Restricting Vehicle Movements ............................................................................. 62 Table 33. Expectation of Persons on Bicycle for Exclusive Movement on Green Bicycle ........................ 63 Table 34. Confusion, Person on Bicycle with Green Bicycle and Red Vehicle ......................................... 63 Table 35. Issues with Concurrent Green Vehicle and Bicycle Signal Faces .............................................. 64 Table 36. Plans to Use Arrows with Bicycle Symbols ............................................................................... 65 Table 37. Use of Yellow and Red Clearance Intervals ............................................................................... 65 Table 38. Research Needed, Signal Timing Guidance ............................................................................... 65 Table 39. Summary of Ranked Potential Research Gaps ........................................................................... 66
List of Figures Figure 1. Typical Red-Yellow-Green Bicycle Signal Faces (Portland, OR) ................................................ 5 Figure 2. MUTCD Figure 4D-4 on Lateral Placement and Visibility of Primary Traffic Signal Faces ....... 9 Figure 3. Human Information Processing Model........................................................................................ 11 Figure 4. Types of Human Factors Evaluation for Traffic Control Devices............................................... 12 Figure 5. Examples of International Bicycle Signal Faces ......................................................................... 13 Figure 6. Signal Location and Phasing, Russell and Sycamore Lane, Davis, CA ...................................... 15 Figure 7. Traffic Signal at Third Street and Prospect Park West (Brooklyn, NY) ..................................... 16 Figure 8. Observed Cyclist Compliance with Traffic Signals .................................................................... 18 Figure 9. Annotated Image of a Cycle Gate................................................................................................ 19 Figure 10. Supplemental Signs: Signals, Turn Prohibition, and Lane Control ........................................... 22 Figure 11. Typical Arrangements of Signal Sections in Bicycle Signal Faces ........................................... 28 Figure 12. Map of Intersections with Bicycle Signal Faces........................................................................ 31 Figure 13. Installation Year of Bicycle Signals .......................................................................................... 32 Figure 14. Plot of Signal Face Mounting Offsets ....................................................................................... 46
