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Road User Understanding of Bicycle Signal Faces on Traffic Signals (2020)

Chapter: Appendix C Research Needs Statements

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Suggested Citation:"Appendix C Research Needs Statements." National Academies of Sciences, Engineering, and Medicine. 2020. Road User Understanding of Bicycle Signal Faces on Traffic Signals. Washington, DC: The National Academies Press. doi: 10.17226/25676.
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Suggested Citation:"Appendix C Research Needs Statements." National Academies of Sciences, Engineering, and Medicine. 2020. Road User Understanding of Bicycle Signal Faces on Traffic Signals. Washington, DC: The National Academies Press. doi: 10.17226/25676.
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Suggested Citation:"Appendix C Research Needs Statements." National Academies of Sciences, Engineering, and Medicine. 2020. Road User Understanding of Bicycle Signal Faces on Traffic Signals. Washington, DC: The National Academies Press. doi: 10.17226/25676.
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Suggested Citation:"Appendix C Research Needs Statements." National Academies of Sciences, Engineering, and Medicine. 2020. Road User Understanding of Bicycle Signal Faces on Traffic Signals. Washington, DC: The National Academies Press. doi: 10.17226/25676.
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Suggested Citation:"Appendix C Research Needs Statements." National Academies of Sciences, Engineering, and Medicine. 2020. Road User Understanding of Bicycle Signal Faces on Traffic Signals. Washington, DC: The National Academies Press. doi: 10.17226/25676.
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Suggested Citation:"Appendix C Research Needs Statements." National Academies of Sciences, Engineering, and Medicine. 2020. Road User Understanding of Bicycle Signal Faces on Traffic Signals. Washington, DC: The National Academies Press. doi: 10.17226/25676.
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Suggested Citation:"Appendix C Research Needs Statements." National Academies of Sciences, Engineering, and Medicine. 2020. Road User Understanding of Bicycle Signal Faces on Traffic Signals. Washington, DC: The National Academies Press. doi: 10.17226/25676.
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Suggested Citation:"Appendix C Research Needs Statements." National Academies of Sciences, Engineering, and Medicine. 2020. Road User Understanding of Bicycle Signal Faces on Traffic Signals. Washington, DC: The National Academies Press. doi: 10.17226/25676.
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Suggested Citation:"Appendix C Research Needs Statements." National Academies of Sciences, Engineering, and Medicine. 2020. Road User Understanding of Bicycle Signal Faces on Traffic Signals. Washington, DC: The National Academies Press. doi: 10.17226/25676.
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Suggested Citation:"Appendix C Research Needs Statements." National Academies of Sciences, Engineering, and Medicine. 2020. Road User Understanding of Bicycle Signal Faces on Traffic Signals. Washington, DC: The National Academies Press. doi: 10.17226/25676.
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Suggested Citation:"Appendix C Research Needs Statements." National Academies of Sciences, Engineering, and Medicine. 2020. Road User Understanding of Bicycle Signal Faces on Traffic Signals. Washington, DC: The National Academies Press. doi: 10.17226/25676.
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Suggested Citation:"Appendix C Research Needs Statements." National Academies of Sciences, Engineering, and Medicine. 2020. Road User Understanding of Bicycle Signal Faces on Traffic Signals. Washington, DC: The National Academies Press. doi: 10.17226/25676.
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Suggested Citation:"Appendix C Research Needs Statements." National Academies of Sciences, Engineering, and Medicine. 2020. Road User Understanding of Bicycle Signal Faces on Traffic Signals. Washington, DC: The National Academies Press. doi: 10.17226/25676.
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Appendix C – Research Needs Statements C-1

1. Problem Title Optimal Methods to Communicate Allowable Protected, or Permissive Movements to Bicyclists at Signalized Intersections 2. Background Bicycle signals provide the opportunity to fully or partially separate bicyclists from conflicting motor vehicle movements. The Interim Approval for bicycle signals (IA-16) in the U.S. was issued by FHWA in 2013 (FHWA, 2013). A recent NCHRP report, “Road User Understanding of Bicycle Signal Faces,” identified over 500 intersections with bicycle signals in use in the U.S. (Monsere et al. 2019). IA-16 limits the use of a bicycle signal face to operations where the bicycle movement is “protected from any simultaneous motor vehicle movement at signalized intersections (FHWA, 2014)”. This requirement suggests that the GREEN BICYCLE display indicates to a person on a bicycle that their movement is protected. Compliance with this provision requires the installation of fully-protected phases and turn lanes for left and right-turns for motor vehicle movements that cross the bicycle lane or signal timing strategies, which limit the available green time for bicyclists to proceed while all adjacent vehicle traffic is stopped. IA-16 also prohibits the use of signs alone to restrict bicycle movements. If it is necessary, turn arrows on the bicycle signal face can be used to communicate allowable movements and to restrict conflicting bicycle movements. This guidance has limited the application of bicycle signals due to lack of road space for turning lanes or concerns about efficiencies and delays for all users. A number of agencies are experimenting with allowing permissive motor vehicle turns across the bicycle facility when bicyclists have displayed the GREEN BICYCLE symbol. Other agencies are using a FLASHING YELLOW BICYCLE to indicate a permissive bicycle movement. In some jurisdictions, the GREEN BICYCLE symbol varies from protected to permissive depending on installation date. Comprehension requires that a road user understand what movements are allowed or required from their position on the roadway. While IA-16 established the GREEN BICYCLE symbol to be a protected movement, some cyclists may interpret the signal similar to the green ball (i.e., yield to other conflicting traffic). The mechanism to communicate whether movements are fully protected or permissive needs further research, as evidenced by ongoing experiments with FLASHING YELLOW BICYCLE indications. Finally, while the use of arrow displays is likely intuitive, there has not been any human factors research to verify this understanding or explore alternatives. 3. Literature Search Summary No research studies were found that examined how to communicate with a person on a bicycle or other road users which movements are allowable from the bicycle lane. With respect to permissive indications, all of the active Request to Experiment on IA-16 involve exceptions to the requirement of protection from any simultaneous motor vehicle movements. Evanston, IL, and Boston, MA, are experimenting with a GREEN BICYCLE allowing permissive right turns across the bicycle facility at multiple intersections in these locations. Minneapolis, MN, Newark, DE are experimenting with a FLASHING YELLOW BICYCLE to indicate a permissive bicycle movement. St. Paul, MN is experimenting with both the FLASHING YELLOW ARROW (FYA) for vehicles and FLASHING YELLOW BICYCLE. Road user understanding of permissive displays for vehicles has focused on left and right turning movements. There are many studies that have explored drivers’ comprehension of FYA signal display indications for left-turns (Asante and Williams, 1993; Bonneson and McCoy, 1993; Noyce and Kacir, 2001, 2002; Drakopoulos and Lyles, 2001; Brehmer et al. 2003; Noyce and Smith, 2003; Knodler et al. 2005, 2006a, 2006b, 2007; Hurwitz et al., 2013; Marnell et al., 2013; Hurwitz et al., 2014). The results also showed that the FYA signal display indication for left-turns was well understood by drivers and led to FYA being adopted for permissive left-turn indications. Though included in the 2009 MUTCD, there is less research on driver comprehension of the use of FYA for right-turns though results from the surveys and driving simulators found the FYA for right-turns was well understood by the drivers (Hurwitz et al., 2018, Jashami et al., 2019, Ryan et al. 2019). Research on the use of FLASHING YELLOW displays for bicycle control is minimal. Recently, the New York City DOT conducted a safety evaluation of bicycle-specific intersection treatments to provide guidance on the appropriate treatment (NYCDOT, 2018). Mixing zones, fully split phases (with bicycle C-2

signals), delayed turn with FYA for vehicles (split LBI), and offset crossing (protected intersections) were evaluated in the study using crash, conflict, and comfort analysis. Of these treatments, fully split phases, delayed turn, and offset crossing used bicycle-specific traffic signals. The study did not document any driver confusion with bicycle traffic signals. Kothuri et al. also studied the safety impacts of Split LBI (FYA for vehicles with GREEN BICYCLE symbol) and mixing zone treatments using an observational study with conflict analysis (Kothuri et al. 2018). Some user confusion (related to the merging behavior and where each entity needed to position themselves) was observed regarding the position of the bicyclists and drivers within the mixing zone. While permissive traffic signal indications for vehicular movements have been well researched, there is a critical need for research to understand how bicyclists comprehend what the allowable movements are at an intersection, and how to best display protected or protected/permissive indications to the bicyclist. 4. Research Objective The objective of the proposed research is to determine how best to communicate with a person on a bicycle and other road users through traffic control devices: • the allowable movements from the bicycle facility; • whether the movement is protected from all simultaneous motor vehicle movements or if the bicyclist should expect conflicts; and • whether the motor vehicle driver should expect to yield to other traffic (i.e., defining the right of way). The following sequence of tasks are needed to complete this research: Task 1 – Review of Literature and State of Practice that includes vehicle codes about legal movements from the bicycle lane and informs the range of traffic signal displays options (arrows, flashing yellow bicycle symbol), pavement markings, signs that have been used in practice. A review of international practices is recommended. Task 2 – Prepare a detailed work plan to determine optimal ways to communicate to the bicyclist allowable, permissive, or protected movements. Depending on the results of Task 1 and input from the panel, the research could consider traffic control designs that are not currently used in U.S. practice. Current guidance and practice assume signal indications designed for motor vehicle drivers can be applied to cycle users generally, unlike pedestrians or light rail transit vehicles that have unique messages. At a minimum, the research should explore comprehension of both drivers and cyclists and give some consideration to people using electric mobility devices (e.g. e-scooters, hoverboards) who might be in the bicycle lane (noting that who is allowed in the bicycle lane varies by jurisdiction). It is anticipated that the following tasks would be required: a) Survey of comprehension – conduct a human factors survey to develop an understanding of actual movements of bicyclists while facing the GREEN BICYCLE symbol from typical intersection configurations, including if they perceive the GREEN BICYCLE symbol to mean that they can only proceed straight through. b) Video data collection and analysis – develop a robust sample of bicyclists interacting with different bicycle traffic signal configurations identified in Task 1. The data collection should be designed to explain the current behaviors of road user. c) Human factors experiment – design of a human factors experiment (controlled lab or field research study) to build a detailed representation of behavioral response to understand comprehension of existing GREEN BICYCLE symbol, comprehension of alternative devices (e.g., BICYCLE symbols for protected movements and 4-section heads with green ball for permissive phases). Consideration should be given to the driver’s understanding and requirements for movements across bikeways. Task 3 – Execute the work plan developed in Task 2 and approved by the NCHRP panel. Task 4 – Prepare final deliverables documenting the results of the various ways to communicate the range of allowable movements to the bicyclists. C-3

Task 5 – Develop guidance documentation for practitioners for inclusion in the MUTCD and other design guidance. 5. Urgency and Potential Benefits The guidance from this research will help practitioners improve safety and operations at intersections where bicyclists are present. This research will aid traffic engineers in the design and development of new signal timing strategies that promote safer interactions between bicyclists and vehicles and improve comprehension by clearly communicating to bicyclists about their movements. Clearly defining who has the right of way is a fundamental principle of safe intersection design; this research would contribute to this definition. 6. Implementation Considerations and Supporters Traffic control devices to communicate allowable movements and signal display indications to indicate protected/permissive movements should be implemented in the field after rigorous human factors research and a thorough understanding of how bicyclists and drivers perceive these devices and display indications. These recommendations could be proposed for review and possible adoption by the Federal Highway Administration and the National Committee on Uniform Traffic Control Devices. City-level transportation officials, represented by NACTO, would also have an interest in the results of this research. 7. Recommended Research Funding and Research Period Recommended Funding: $350,000 Research Period: 24 months 8. Problem Statement Author(s) Chris Monsere, Portland State University, 503-725-9746, monsere@pdx.edu David Hurwitz, Oregon State University, 541-737-9242, david.hurwitz@oregonstate.edu Sirisha Kothuri, Portland State University, 503-725-4208, skothuri@pdx.edu Christina Fink, Toole Design Group, 301-927-1900, cfink@tooledesign.com 9. Others Supporting the Problem Statement To be completed. 10. Potential Panel Members To be completed. 11. Person Submitting the Problem Statement To be completed. C-4

1. Problem Title Evaluation of Size, Placement, and Orientation of Bicycle Signal Faces on Bicyclist and Driver Comprehension and Compliance 2. Background As cycling rates continue to rise in North America, implementing bicycle-oriented traffic control devices has become increasingly necessary. Cities are installing bicycle signals at existing intersections with motor vehicle traffic, which increases intersection complexity. Increasing intersection complexity may affect fundamental MUTCD principles of traffic control devices; these devices must: fulfill a need; command attention; convey a clear, simple meaning; command respect from road users, and give adequate time for a proper response. If the devices do not meet these aims, operations, and safety for people riding bicycles as well as other travelers may be negatively affected. FHWA’s Interim Approval of bicycle signals faces (IA-16) provides guidance on the design and placement of bicycle signals at intersections and relative to other vehicular traffic signal indications. NACTO’s Urban Bikeway Design Guide and the MassDOT Separated Bike Lane Planning and Design Guide provide additional guidance. Cities, however, have implemented a wide variety of bicycle signal designs, and there is limited information on how the design and placement of signal faces positively or negatively affect bicycle operations and safety. For example, there is no consensus on the horizontal and vertical distance from vehicular traffic signals or the use of nearside signal heads. In a recent inventory of approximately 500 bicycle signal installations in the U.S. cited in the NCHRP report “Road User Understanding of Bicycle Signal Faces” a majority (51%) use two or more bicycle signal heads per approach. However, there is no standard for the placement of the supplemental face. In the inventory, locations that had two or more bicycle signal heads per approach typically used a farside/nearside arrangement. There are concerns that motorists may be confused by the green bicycle signal indication and proceed despite the vehicular signal heads displaying a red indication. Therefore, some jurisdictions have installed louvers to restrict motorist visibility for bicycle signal indications. From the standpoint of uniformity, existing practices for communicating to bicyclists operating is anything but uniform as they are often directed to follow traffic signals, pedestrian signals, and bicycle signals at subsequent signalized intersections within a single corridor. Overall, there is limited information on which bicycle signal design best meets MUTCD traffic control device principles and which strategies support uniformity principles for all users under different bikeway design configurations. With an increase in the use of bike lanes by people using electric mobility devices (e.g., e-scooters, hoverboards), there are also questions of comprehension and applicability of signal faces with bicycle symbols to these users. Will they understand these signals are applicable to them? Finally, practitioners question whether bicycle signal design affects user comprehension and, ultimately traffic signal compliance. Noncompliant behavior, like running red signals, is generally unacceptable behavior for motorists, but does the bicycle signal design affect bicycle user signal compliance? There is an acute need to understand how bicycle signal indications should be designed, positioned, and installed to inform this option for providing safe and comfortable bicycle facilities at intersections. 3. Literature Search Summary There is limited research previously performed on how a bicyclist’s behavior is affected by the size, placement, and orientation of bicycle traffic signals. Bicycle signals have been designed and installed based on principles of vehicle traffic signal installations. Now with more bicyclists and bicycle traffic signals, there is greater variability in how these traffic control devices are designed and implemented. Ultimately, this impacts how they command respect from roadway users. Although some research has been performed to test supplementary functions of traffic control devices, such as the blue light feedback detector device, little to no research has been performed on how bicycle traffic signals themselves are perceived (Boudart et al. 2015). Additionally, while much research has explored compliance in general (Johnson et al., 2011, Johnson et al. 2013, Monsere et al., 2013, Monsere et al. 2014, Richardson et al. 2015), little research has been performed on the factors for bicyclist compliance at bicycle-specific signals as it relates to size, placement, and orientation of signal faces. If research is C-5

performed on the design and placement of bicycle traffic signals, then solutions can be devised to improve traffic control device compliance for bicycle users. 4. Research Objective The objective of this research is to determine how the design (e.g., lens size, placement, number, orientation) of bicycle signal heads influences both motorists’ and bicyclists’ comprehension of bicycle signals. The research should explore discernable differences in visual comprehensions, such as the relationship between the proximity of bicycle and vehicular traffic signal indications and comprehension, the interaction between the bicyclist and the signal/intersection based on the near/far side installations, and the appropriateness of supplemental bicycle signage. At a minimum, the research should explore comprehension of both drivers and cyclists and give some consideration to people using electric mobility devices (e.g. e-scooters, hoverboards) who might be in the bicycle lane (noting that who is allowed in the bicycle lane varies by jurisdiction). The following sequence of tasks are needed to complete this research: Task 1 – Review of Literature and State of Practice on the design and placement of bicycle signals at intersections with consideration for international design. European countries tend to use smaller indications and height differences to distinguish bicycle signal controls. One outcome of this task will be to identify the existing standards, gaps in practice, and the potential configurations to explore in the research. Task 2 – Prepare a detailed work plan to determine optimal design and placement of bicycle signals and how compliance with a bicycle signal relates to comprehension. At a minimum, the research should evaluate the number of bicycle signal heads per approach, nearside or farside installations, size of indication (12”, 8”, 4”), horizontal and vertical distance of bicycle signals to vehicle signals (includes louvers, backplates, and distance from bicycle stop line to bicycle signal. It is anticipated that the following experimental tasks may be required: a) Observed behaviors and responses in the field using a robust sample of design options identified in Task 1. The observational data should seek to establish behaviors and responses of road users using naturalistic data collection techniques such as eye-tracking. b) Driving and bicycling simulator experiments of a set of scenarios to be developed in a virtual built environment in which both bicyclists and motorists should interact with a variety of bicycle signal configurations. The simulator experiment should be based on information gathered from the field data. At least 30 drivers and 30 bicyclists should participate in the experiments and performance measures such as visual attention, compliance with right-of-way conventions, and time-to-conflict measures can be collected and analyzed. c) Closed-course test tracks that seek to validate the design characteristics that perform best through a usability study to confirm the recommended design solutions meet the desired motorist and bicyclist responses. Task 3 – Execute the work plan developed in Task 2 and approved by the NCHRP panel. Task 4 – Prepare a final report documenting the results of the work plan. The final report will distill the key findings of the research and identify best practices for bicycle signal design and installation. Task 5 – Develop guidance documentation for practitioners based on the final report findings. 5. Urgency and Potential Benefits This research should produce a best practice study that practitioners can use to design intersections with bicycle signals that users on bicycles or in vehicles can easily understand. A vast amount of information is conveyed to users approaching intersections in addition to traffic signal heads, including signs (e.g., regulatory, warning, informational) and pavement markings. This research should provide guidance on how to convey only the necessary information for bicyclists to clearly assist all users through the intersection safely. Bicycle signals mirror vehicular signals in many ways, which may cause confusion. For example, vehicular traffic signal indications are placed within a driver’s cone of vision as they approach an intersection. Does the bicyclist cone of vision differ from a driver’s cone of vision? Is there a benefit to the overall operations of allowing the motor vehicle driver to see the bicycle signal face? The research will C-6

help practitioners design bicycle traffic signals that clearly communicate to people riding bicycles as well as people driving, and allow users to navigate safely through intersections. The results of this research may also increase compliance with red bicycle signals. as there are many factors that influence someone’s decision to run a red light (Wu, 2011 and Fietsberaad, 2003). The design and placement of bicycle signals is one critical factor that needs to be studied. 6. Implementation Considerations and Supporters Within a state DOT, the results of this research would likely affect the workflow of the state traffic engineer, the program manager responsible for signalized intersections, and the coordinator for active transportation modes. To implement the findings, policy and design guides concerned with traffic control devices and signalized intersection design would need to be revised and distributed to engineers across the state responsible for implementing the new standards. These recommendations could be proposed for review and possible adoption by the Federal Highway Administration and the National Committee on Uniform Traffic Control Devices. City-level transportation officials, represented by NACTO, would also have interest in the results of this research. 7. Recommended Research Funding and Research Period Recommended Funding: $350,000. Research Period: 24 months. 8. Problem Statement Author(s) David Hurwitz, Oregon State University, 541-737-9242, david.hurwitz@oregonstate.edu Chris Monsere, Portland State University, 503-725-9746, monsere@pdx.edu Douglas Cobb, Oregon State University, 540-533-6560, cobbdo@oregonstate.edu Sirisha Kothuri, Portland State University, 503-725-4208, skothuri@pdx.edu Christina Fink, Toole Design Group, 301-927-1900, cfink@tooledesign.com 9. Others Supporting the Problem Statement To be completed. 10. Potential Panel Members To be completed. 11. Person Submitting the Problem Statement To be completed. C-7

1. Problem Title Guidance on Visibility and Detection of Bicycle Symbols in Signal Faces by Lens Size and Distance 2. Background According to the Manual on Uniform Traffic Control Devices (MUTCD), in addition to fulfilling a need, traffic control devices should command attention, convey a clear, simple meaning, command respect from road users, and give adequate time for proper response. For these four criteria to be met, any and all traffic control devices should be optimized for comprehension, legibility, and conspicuity. If a traffic control device does not adequately provide these three elements, road users will not effectively interact with surface transportation infrastructure, which can negatively impact roadway safety. This is especially important as the number of vulnerable users increases on roadways. To accommodate this trend in roadway cycling, bicycle signals with the bicycle symbol in the face have begun to appear in cities across the United States. Since bicycle signals were introduced in Davis, California in 1994, they have served to provide both specific indications and to communicate priority to cyclists within the functional area of signalized intersections. While visual awareness of these bicycle signals plays a crucial role in a cyclist’s decision making and riding practices, it also influences driver comprehension and behavior. Of particular concern is a driver’s or bicyclist’s ability to detect, identify, and discern bicycle symbols in signal faces at an intersection. Conspicuity and the distance at which the bicycle symbol in the signal face is distinguishable is key to the safety of bicyclists and other road users. For example, one source of potential driver confusion is that the color of the bicycle signal’s indications is the same as vehicular signals. Additionally, at some distances and LED intensities, the bicycle symbol may not be distinguishable from a circular display, causing additional confusion. A similar issue was identified in the first light-rail transit (LRT) signals, which led to the adoption of a monochromatic and unique signal symbol (Korve, 1996). IA-16 currently requires far side bicycle signals to use 8- or 12-inch lenses, while near side lenses can be 4-, 8-, or 12-in. The guidance for signal face sizing (lens size) by distance appears to be derived primarily from the guidance for motor vehicle signals. There are many more details regarding the design of the bicycle symbol that could contribute to visibility challenges for some drivers, especially in low-light or nighttime conditions. While optimal placement, shielding, and supplemental signs can address some of these issues, research should be conducted to establish guidance on detection distances by lens size and intensity. In addition to the detection distance of the bicycle symbol in the signal face, the design of the bicycle symbol within the lens face itself plays a significant role in both motorist and bicyclist comprehension. Research on bicycle signal face design and detection distance should be conducted to fill this knowledge gap. 3. Literature Search Summary No published research studies were found that have directly addressed the visibility of the bicycle symbol in the signal lens. Visibility includes placement for optimal detection by road users, conspicuity of the lens, and detection distances. There are two separate issues related to the comprehension of the bicycle symbol in the signal face: 1) recognizing that the symbol face denotes the signal as exclusive for bicycles, and 2) knowing which movements are allowed by the displayed indications. No published research studies were found that have directly addressed comprehension of the bicycle symbol in the signal face, either for the bicyclist or drivers. While no published research studies were found on the visibility and comprehension of the bicycle signal face, many practice reports include brief assessments thereof. A published evaluation was conducted in 1996 in response to the installation of the bicycle signal face in Davis, California by Pelz et al. (1996). The study, which included a before-after survey and review of crash data, noted that a large percentage (66%) of participants found that the inclusion of the bicycle signal face with the standard signal head was not confusing. Additionally, crash data did not reveal the presence of safety issues. While there are slight variations in the symbol presented internationally, little research or guidance has been provided on the optimal design of the signal face. There is no published human factors research on the currently approved bicycle symbol. In a review of signs and signals for cyclists and C-8

pedestrians in thirteen countries (Austria, Belgium, Denmark, France, Germany, Italy, Norway, Poland, Russian Federation, Spain, Switzerland, United Kingdom and the U.S.) for the United Nations, Hiron et al. (2014) found that nearly all symbols feature a similar version of the bicycle (although sometimes a person is shown riding the bicycle). The study notes that most of the countries reviewed also have three-section faces with bicycle symbols in the lens. Similarly, while many researchers have evaluated the conspicuity of standard traffic signals, no studies have been conducted regarding lens detection and conspicuity of bicycle signal faces. Currently, there is no comprehensive research on the size of the signal lens (4-, 8-, or 12-inch), the design of the bicycle symbol within the lens, and longitudinal placement of the signal head to optimize the detection distance from the stop line for cyclists. Since the symbol plays a significant role in distinguishing between separate user controls at an intersection, refining the design of existing symbols could improve the conspicuity of the signal. 4. Research Objective The proposed research will develop guidelines for the overall design of the bicycle symbol in the signal lens including lens size and brightness to improve conspicuity, improved bicycle symbol design in the signal face for optimal detection, and determination of bicycle signal face detection distance for safer driving/cycling practices and bicycle lens size for various applications of far side and near side placement. The following sequence of tasks are needed to complete this research: Task 1 – Review of literature on signal placement and visibility distance, including research methods and analysis techniques. Task 2 – Review of design practice for bicycle signal lens size selection and other factors as they relate to visibility distances. The review should identify current practices of both national and international agencies to determine a target range of options for the research to explore for lens size, bicycle symbol design, and detection distances. Task 3 – Human factors experiment to establish visibility distances, likely using a sign simulator or a closed test-track environment. The experiments should include measurements for the parameters identified in Tasks 1 and 2. Both persons driving and cycling should be included in the subject tests. At a minimum, visibility and detection should be studied during daylight and low light conditions and for modifications to the current bicycle symbol. Task 4 – Prepare a final report documenting the key findings of the research and identify best practices for bicycle signal design and installation. Task 5 – Develop guidance language for inclusion in the MUTCD and other design guides. 5. Urgency and Potential Benefits The conspicuity of traffic signals has been cited as a factor in intersection collisions, so improving their visibility can contribute to improved safety. Additional research on the design and placement of bicycle signals has the potential to expand existing knowledge and state of practice to determine the ideal bicycle symbol design for detection and visibility distance for bicyclists. These efforts would allow researchers and practitioners to optimize safety and minimize the conflicts experienced for people on bikes while they approach and proceed through the intersection. Research findings could also help to expand MUTCD guidance on bicycle signal lens placement within the intersection. 6. Implementation Considerations and Supporters When evaluating new traffic control devices or technologies, it is important to remember that new requirements or guidance can only be introduced once they have been evaluated through research and adopted by the MUTCD through FHWA. For example, it is typically easy to develop new designs and symbols that are intended to appear simple and, therefore, effective. However, what seems to be effective in design may not necessarily result in effective driver comprehension and behavioral reaction. Therefore, research of traffic control devices, and even more so with signals that will be interacted with by various road users, requires precise and detailed research. The results of this research can not only be used to establish a foundation for bicycle signal usage guidelines and recommendations but also be used to improve bicyclist safety along highly used corridors. These recommendations could be proposed for C-9

review and possible adoption by the Federal Highway Administration and the National Committee on Uniform Traffic Control Devices. City-level transportation officials, represented by NACTO, would also have an interest in the results of this research. 7. Recommended Research Funding and Research Period Research Funding: $200,000 Research Period: 18 months 8. Problem Statement Author(s) Christina Fink, Toole Design Group, 301-927-1900, cfink@tooledesign.com Chris Monsere, Portland State University, 503-725-9746, monsere@pdx.edu David Hurwitz, Oregon State University, 541-737-9242, david.hurwitz@oregonstate.edu Sirisha Kothuri, Portland State University, 503-725-4208, skothuri@pdx.edu 9. Others Supporting the Problem Statement To be completed. 10. Potential Panel Members To be completed. 11. Person Submitting the Problem Statement To be completed. C-10

References Cited in Research Needs Statements Optimal Methods to Communicate Allowable Protected, or Permissive Movements to Bicyclists at Signalized Intersections Asante, S.A., S.A. Ardekani, and J.C. Williams. 1993. Selection Criteria for Left-Turn Phasing, Indication Sequence, and Auxiliary Sign. Report 1256-1F, Civil Engineering Department, University of Texas at Arlington, Arlington, TX. Bonneson, J.A., and P.T. McCoy. 1993. Evaluation of Protected/Permitted Left-Turn Traffic Signal Displays. Report TRP- 02-27-92. Civil Engineering Department, University of Nebraska- Lincoln, Lincoln, NE. Brehmer, C. L., K. C. Kacir, D. A. Noyce, and M. P. Manser. 2003. NCHRP Report 493: Evaluation of Traffic Signal Displays for Protected/Permissive Left-Turn Control. Transportation Research Board of the National Academies, Washington, D.C. Drakopoulos, A., and R.W. Lyles. 2001. “Use of Multivariate Multiple Response Analysis of Variance Models to Evaluate Driver Comprehension Errors of Flashing Traffic Signal Operations.” Journal of Safety Research, 32 (1), 85- 106. FHWA. 2013. Interim Approval for Optional Use of a Bicycle Signal Face (IA-16). https://mutcd.fhwa.dot.gov/resources/interim_approval/ia16/ FHWA. 2014. Official Interpretation #9(09)-47 (I) on Clarification of IA-16. https://mutcd.fhwa.dot.gov/resources/interpretations/9_09_47.htm Hurwitz, D., C. Monsere, H. Tuss, K. Paulsen, and P. Marnell. 2013a. Improved Pedestrian Safety at Signalized Intersections Operating the Flashing Yellow Arrow. Oregon Transportation Research and Education Consortium (OTREC), OTREC-RR-13-02, Portland, OR. Hurwitz, D., H. Jashami, K. Buker, C. Monsere, S. Kothuri, and A. Kading. 2018. Towards Safer Protected/Permitted Right-Turn Phasing for Drivers, Bicyclists and Pedestrians. Final Report, SPR 789, Oregon Department of Transportation. Hurwitz, D. S., C. M. Monsere, P. Marnell, and K. Paulsen. 2014. Three- or Four-Section Displays for Permissive Left-Turns? Transportation Research Record: Journal of the Transportation Research Board, Vol. 2463, pp. 1– 9. https://doi.org/10.3141/2463-01. Jashami, H., D.S. Hurwitz, C. Monsere, and S. Kothuri. 2019. “Evaluation of Driver Comprehension and Visual Attention of the Flashing Yellow Arrow Display for Permissive Right Turns.” Transportation Research Record: Journal of the Transportation Research Board, Vol. 2673, pp. 397–407. Knodler, M.A. Jr., D.A. Noyce, K.C. Kacir, and C.L. Brehmer. 2005. ”Evaluation of Flashing Yellow Arrow in Traffic Signal Displays with Simultaneous Permissive Indications.” Transportation Research Record: Journal of the Transportation Research Board, Vol. 1918, pp. 46–55. Knodler, M. A., D. A. Noyce, K. C. Kacir, and C. L. Brehmer. Analysis of Driver and Pedestrian Comprehension of Requirements for Permissive Left-Turn Applications. “Transportation Research Record: Journal of the Transportation Research Board, Vol. 1982, pp. 65–75. Knodler, M.A. Jr., D.A. Noyce, K.C. Kacir, and C.L. Brehmer. 2006b.” Potential Application of Flashing Yellow Arrow Permissive Indication in Separated Left-Turn Lanes.” Transportation Research Record: Journal of the Transportation Research Board, Vol. 1973, pp. 10–17. Knodler, M.A. Jr., D.A. Noyce, K.C. Kacir, and C.L. Brehmer. 2007. “An Evaluation of Driver Comprehension of Solid Yellow Indications Resulting from Implementation of Flashing Yellow Arrow”. Presented at the 86th Annual Meeting of the Transportation Research Board, Washington, D.C. C-11

Kothuri, S., A. Kading, A. Schrope, K. White, E. Smaglik, C. Aquilar, and W. Gil. 2018. Addressing Bicycle-Vehicle Conflicts with Signal Control Strategies. Final Report. National Institute for Transportation and Communities. Marnell, P., H. Tuss, D. Hurwitz, K. Paulsen, and C. Monsere. 2013. “Permissive Left-Turn Behavior at the Flashing Yellow Arrow in the Presence of Pedestrians.” In Conference Proceedings of the 7th International Driving Symposium on Human Factors in Driver Assessment, Training, and Vehicle Design, Bolton Landing, NY, pp. 488-494. New York City Department of Transportation. 2018. Cycling at Crossroads. The Design Future of New York City Intersections. http://www.nyc.gov/html/dot/downloads/pdf/cycling-at-a-crossroads-2018.pdf Noyce, D.A. and K.C. Kacir. 2001. “Drivers’ Understanding of Protected-Permitted Left-Turn Signal Displays.” Transportation Research Record: Journal of the Transportation Research Board, Vol. 1754, pp. 1–10. Noyce, D.A. and K.C. Kacir. 2002. “Driver Understanding of Simultaneous Traffic Signal Indications in Protected Left Turns.” Transportation Research Record: Journal of the Transportation Research Board, Vol. 1801, pp. 18– 26. Noyce, D.A., and C.R. Smith. 2003. “Driving Simulators Evaluation of Novel Traffic-Control Devices: Protected- Permissive Left-Turn Signal Display Analysis”. Transportation Research Record: Journal of the Transportation Research Board, Vol. 1844, pp. 25–34. Ryan A., E. Casola, C. Fitzpatrick, M. Knodler, “Flashing yellow arrows for right turn applications: A driving simulator study and static evaluation analysis,” Transportation Research Part F: Traffic Psychology and Behaviour, Volume 66, 2019, Pages 324-338, https://doi.org/10.1016/j.trf.2019.09.013 Evaluation of Size, Placement, and Orientation of Bicycle Signal Faces on Bicyclist and Driver Comprehension and Compliance Boudart, J., R. Liu, P. Koonce, and L. Okimoto. 2015. Assessment of Bicyclist Behavior at Traffic Signals with a Detector Confirmation Feedback Device. Transportation Research Record: Journal of the Transportation Research Board, Vol. 2520, pp. 61–66. https://doi.org/10.3141/2520-08. Fietsberaad. The Bicycle Friendliness of Traffic Control Systems. Fietsberaad, Amsterdam, 2003. Guo, Y., Z. Li, P. Liu, and Y. Wu. 2015. Analysis of Red-Light Running Behaviors of Bicycle Riders at Signalized Bicycle Crossing Facilities in China. Presented at 93rd Annual Meeting of the Transportation Research Board, Washington D.C. Johnson, M., S. Newstead, J. Charlton, and J. Oxley. 2011. “Riding Through Red Lights: The Rate, Characteristics and Risk Factors of Non-Compliant Urban Commuter Cyclists.” Accident Analysis and Prevention, 43(1), pp. 323- 328. Johnson, M., S. Newstead, J. Charlton, and J. Oxley. 2013. “Why do Cyclists Infringe at Red Lights? An Investigation of Australian Cyclists’ Reasons for Red Light Infringement.” Accident Analysis and Prevention, Vol. 50, pp. 840-847. Monsere, C., M. Figliozzi, S. Thompson, and K. Paulsen. 2013. Operational Guidance for Bicycle-Specific Traffic Signals in the United States. Final Report, SPR 747/OTREC 2012FG, Oregon Department of Transportation and Oregon Research and Education Consortium. Monsere, C., J. Dill, N. McNeil, K. Clifton, N. Foster, T. Goddard, M.Berkow, J.Gilpin, K. Voros, D.van Hengel, J.Parks. Lessons From The Green Lanes: Evaluating Protected Bike Lanes In The U.S. Final Report, National Institute for Transportation and Communities (NITC), NITC-RR583, June 2014. Pelz, D., T. Bustos, and J. Flecker, J. 1996. The Use of Bicycle Signal Heads at Signalized Intersections. Davis California. C-12

Richardson, M. and B. Caulfield. 2015. “Investigating Traffic Light Violations by Cyclists in Dublin City Center.” Accident Analysis & Prevention, Vol. 84, pp. 65-73. Wu, C., L. Yao, and K. Zhang. The Red-Light Running Behavior of Electric Bike Riders and Cyclists at Urban Intersections in China: An Observational Study. Accident Analysis and Prevention. 2011. Guidance on Visibility and Detection of Bicycle Symbols in Signal Faces by Lens Size and Distance Hiron, B, A. Isler, and F. Tortel. 2014. “Signs and signals for cyclists and pedestrians: comparison of rules and practices in 13 countries.” Transport Research Arena (TRA) 5th Conference: Transport Solutions from Research to Deployment, Institut Francais des Sciences et Technologies des Transports, de l'amacnagement et des Racseaux (IFSTTAR). Korve, H., J. Farran, and D. Mansel. 1996. Integration on Light Rail Transit into City Streets. TCRP Report 17, Transportation Research Board, National Research Council. Pelz, D., T. Bustos, and J. Flecker, J. 1996. The Use of Bicycle Signal Heads at Signalized Intersections. Davis California. C-13

Road User Understanding of Bicycle Signal Faces on Traffic Signals Get This Book
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Prior to 2013, the use of bicycle-specific signals in the U.S. was limited to a few jurisdictions. However, in recent years, the number of installations has grown rapidly. This research identified more than 500 intersections using bicycle signals in a variety of contexts.

Despite the recent approval and practice, the TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 273: Road User Understanding of Bicycle Signal Faces on Traffic Signals explores the questions that remain regarding road-user understanding of bicycle signals.

The objective of this research was to summarize and synthesize the U.S. experience with bicycle signal installations to identify any remaining gaps in understanding road-user comprehension and compliance with bicycle signals that could be effectively addressed through further research.

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