Design Guidance for Channelized Right-Turn Lanes (2014)

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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. 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, FRA, FTA, Transit Development Corporation, or AOC 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 Research Council, 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 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. Upon the authority of the charter granted to it by the 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 achievements of engineers. Dr. C. D. Mote, Jr., is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Victor J. Dzau is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Ralph J. Cicerone and Dr. C. D. Mote, Jr., are chair and vice chair, respectively, of the National Research Council. The Transportation Research Board is one of six major divisions of the National Research Council. The mission of the Transporta- tion Research Board is to provide leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisciplinary, 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 Transportation, and other organizations and individu- als interested in the development of transportation. www.TRB.org www.national-academies.org

Contents Figures............................................................................................................................................. ii Tables ............................................................................................................................................. iii Author Acknowledgements .............................................................................................................v Abstract .......................................................................................................................................... vi Executive Summary ...................................................................................................................... vii Chapter 1. Introduction ...........................................................................................................1 Background ............................................................................................................1 1.1 Research Objectives and Scope .............................................................................3 1.2 Organization of This Report ..................................................................................3 1.3 Chapter 2. State of Knowledge and Practice with Channelized Right-Turn Lanes ................5 Literature Review ..................................................................................................5 2.1 Highway Agency Experience ..............................................................................20 2.2 Chapter 3. Pedestrian Behavior at Channelized Right-Turn Lanes ......................................28 Observational Field Studies .................................................................................28 3.1 Interviews with Orientation and Mobility Specialists .........................................37 3.2 Summary of Findings from Observational Field Studies and Interviews with 3.3 Orientation and Mobility Specialists ...................................................................39 Chapter 4. Traffic Operational Analysis of Channelized Right-Turn Lanes ........................41 Traffic Operational Modeling ..............................................................................42 4.1 Base Modeling Results for Each Configuration ..................................................46 4.2 Impacts of Pedestrians on Base Configuration Results .......................................52 4.3 Impacts of Geometric Characteristics and Signal Phasing on Channelized 4.4 Right-Turn Lane Delay ........................................................................................56 Summary of Traffic Operational Analysis Findings ...........................................59 4.5 Chapter 5. Safety Analysis of Channelized Right Turns ......................................................61 Database Development ........................................................................................61 5.1 Cross-Sectional Crash Analysis Approach ..........................................................62 5.2 Cross-Sectional Crash Analysis Results ..............................................................64 5.3 Summary of Safety Analysis ...............................................................................91 5.4 Chapter 6. Interpretation of Results and Design Guidance ...................................................93 Application of Channelized Right-Turn Lanes....................................................94 6.1 Design Issues Related to Channelized Right-Turn Lanes ...................................95 6.2 Chapter 7. Conclusions and Recommendations ..................................................................100 Conclusions........................................................................................................100 7.1 Recommendations ..............................................................................................101 7.2 Chapter 8. References .........................................................................................................103 Appendix A. Design Guide for Channelized Right-Turn Lanes ................................................ A-1 Appendix B. Revised Text on Channelized Right-Turn Lanes for the AASHTO Green Book ......................................................................................B-1 i

Figures Figure 1. Typical Intersection with Channelized Right-Turn Lanes ...............................................1 Figure 2. Channelized Right-Turn Lane Study Location for NCHRP Project 3-78A (21) ...........13 Figure 3. Blue Pavement Marking Treatment at Channelized Right-turn Lane (27) ....................15 Figure 4. Signs Used in Oregon Blue Bike Lane Program (27) ....................................................17 Figure 5. Combined Bicycle Lane/Right-Turn Lane (27) .............................................................18 Figure 6. Traditional Bike Lane/Right-Turn Lane (28) .................................................................18 Figure 7. Alternative Crosswalk Locations ...................................................................................22 Figure 8. Isosceles-Triangle Island Shape Used by WisDOT .......................................................23 Figure 9. Typical Channelized Right-Turn Lanes with Differing Entry Angles to the Cross Street [Adapted From (14)] ...................................................................................................24 Figure 10. Channelized Right-Turn Lane with Vehicle Yielding to Pedestrian ............................28 Figure 11. Observational Field Study Locations ...........................................................................30 Figure 12. Data Collection Field Setup for an Intersection in Baltimore, Maryland .....................30 Figure 13. Data Collection Field Setup for an Intersection in San Francisco, California .............31 Figure 14. Raised Crosswalk at Channelized Right-Turn Lane in Boulder, Colorado ..................36 Figure 15. Intersection Configurations for Traffic Operational Analysis ......................................43 Figure 16. RTOR and Pedestrian Crossing Movement Considered in Analysis ...........................46 Figure 17. Delay Comparison of Configuration 1 - Conventional Right-Turn Lane (With and Without RTOR) ..........................................................................................................47 Figure 18. Delay for Configuration 2 (Yield-Controlled Channelized Right-Turn Lane) ............48 Figure 19. Delay for Configuration 3 (Signalized Channelized Right-Turn Lane) .......................48 Figure 20. Delay Comparison of Configurations 1, 2, and 3 .........................................................49 Figure 21. Right-Turn Delay Reduction Due to a Channelized Right-Turn Lane Configuration 1 (RTOR) Vs. Configuration 2 ......................................................................................50 Figure 22. Right Turn Delay Reduction Due to a Channelized Right-Turn Lane Configuration 1 (Without RTOR) Versus Configuration 2 ..................................................................51 Figure 23. Delay Due to Pedestrian Crossings—Configuration 2 Channelized Right Turn Lane (300 veh/h Right-Turn and 800 veh/h Conflicting Through) .....................................53 Figure 24. Delay Due to Pedestrian Crossings—Configuration 2 Channelized Right-Turn Lane (800 veh/h Conflicting Through Volume) ..................................................................54 Figure 25. Pedestrian Delay Waiting for a Gap in Right-Turning Traffic .....................................55 Figure 26. Delay Comparison With Acceleration Lane (Configuration 2) ...................................56 Figure 27. Right-Turn Overlap ......................................................................................................58 Figure 28. Intersection Turning Movements Relative to an Intersection Approach (Approach 1) with a Specific Right-Turn Treatment (CRT, RTL, or STR) .....................................63 Figure 29. Summary of Analysis Model 1 Inputs and Criteria ......................................................65 Figure 30. Summary of Analysis Model 2 Inputs and Criteria ......................................................69 Figure 31. Summary of Analysis Model 3 Inputs and Criteria ......................................................73 Figure 32. Summary of Analysis Model 4 Inputs and Criteria ......................................................76 Figure 33. Summary of Analysis Model 5 Inputs and Criteria ......................................................79 Figure 34. Summary of Analysis Model 6 Inputs and Criteria ......................................................83 Figure 35. Summary of Analysis Model 7 Inputs and Criteria ......................................................88 Figure 36. Illustration of Three Right-Turn Treatment Types—STR, RTL, and CRT. ................93 Figure 37. Right-Turn Overlap ......................................................................................................99 ii

Tables Table 1. Comparison of Crash History for Common Right-Turn Treatments (4) ...........................6 Table 2. Annual Right-Turn Crashes by Type of Right-Turn Treatment (5) ..................................7 Table 3. Locations Where Highway Agencies Place Pedestrian Crosswalks at Channelized Right-Turn Roadways (3) ...........................................................................................22 Table 4. Innovative Traffic Control Devices at Channelized Right-Turn Roadways (3) ..............25 Table 5. General Strategies Used by Highway Agencies to Assist Pedestrians with Vision Impairment (3) ............................................................................................................26 Table 6. Pedestrian Issues Considered in Determining the Radius or Width of Channelized Right-Turn Roadway (3) .............................................................................................27 Table 7. Vehicle and Pedestrian Counts During Evening Peak Period (5:00 p.m. to 6:00 p.m.) ..33 Table 8. Comparison of Pedestrian and Motorist Behavior Between Boulder, Colorado, Sites and Other Sites ............................................................................................................37 Table 9. HCS and Synchro Right-Turn Movement Delay Calibration Results .............................45 Table 10. Delay Impacts of Crosswalk Location (300 vph and 50 ped/h) ....................................54 Table 11. Delay Impacts of Channelized Right-Turn Lane Speed/Radius for Configuration 2 ....57 Table 12. Delay Impacts of Adding Additional Green Time to Right-Turn Movement ...............58 Table 13. Mean and Median Motor-Vehicle Volumes by Intersection Type—Analysis Model 1 .......................................................................................................................66 Table 14. Seven (7)-Year Total and FI Motor-Vehicle Crash Counts by Intersection Approach—Analysis Model 1 ....................................................................................66 Table 15. Regression Results for Motor-Vehicle Crash Models—Analysis Model 1 ...................67 Table 16. Yearly Motor-Vehicle Crash Predictions—Analysis Model 1 ......................................68 Table 17. Mean and Median Motor-Vehicle Volumes by Intersection Type—Analysis Model 2 .......................................................................................................................70 Table 18. Seven (7)-Year Total and FI Motor-Vehicle Crash Counts by Intersection Approach—Analysis Model 2 ....................................................................................70 Table 19. Regression Results for Motor-Vehicle Crash Models—Analysis Model 2 ...................71 Table 20. Yearly Motor-Vehicle Crash Predictions—Analysis Model 2 ......................................71 Table 21. Mean and Median Motor-Vehicle Volumes by Intersection Type—Analysis Model 3 .......................................................................................................................72 Table 22. Seven (7)-Year Total and FI Motor-Vehicle Crash Counts by Intersection Approach—Analysis Model 3 ....................................................................................72 Table 23. Regression Results for Motor-Vehicle Crash Models—Analysis Model 3 ...................74 Table 24. Yearly Motor-Vehicle Crash Predictions—Analysis Model 3 ......................................74 Table 25. Mean and Median Motor-Vehicle Volumes by Intersection Type—Analysis Model 4 .......................................................................................................................75 Table 26. Seven (7)-Year Total and FI Motor-Vehicle Crash Counts by Intersection Approach— Analysis Model 4 ........................................................................................................75 Table 27. Regression Results for Motor-Vehicle Crash Models—Analysis Model 4 ...................77 Table 28. Contrast Results for Motor-Vehicle Crash Models—Analysis Model 4 .......................78 Table 29. Yearly Motor-Vehicle Crash Predictions—Analysis Model 4 ......................................78 Table 30. Mean and Median Motor-Vehicle Volumes by Intersection Type—Analysis Model 5 .......................................................................................................................80 iii

Table 31. Seven (7)-Year Total and FI Motor-Vehicle Crash Counts by Intersection Approach—Analysis Model 5 ....................................................................................80 Table 32. Regression Results for Motor-Vehicle Crash Models—Analysis Model 5 ...................81 Table 33. Yearly Motor-Vehicle Crash Predictions—Analysis Model 5 ......................................81 Table 34. Mean and Median Motor-Vehicle Volumes by Intersection Type—Analysis Model 6 .......................................................................................................................82 Table 35. Seven (7)-Year Total and FI Motor-Vehicle Crash Counts by Intersection Approach—Analysis Model 6 ....................................................................................84 Table 36. Regression Results for Motor-Vehicle Crash Models—Analysis Model 6 ...................84 Table 37. Contrast Results for Motor-Vehicle Crash Models—Analysis Models 6 .....................86 Table 38. Yearly Motor-Vehicle Crash Predictions—Analysis Models 6 ....................................87 Table 39. Mean and Median Motor-Vehicle and Pedestrian Volumes by Intersection Type—Analysis Model 7 ............................................................................................89 Table 40. Seven (7)-Year Total and FI Pedestrian Counts by Intersection Approach—Analysis Model 7 .......................................................................................................................89 Table 41. Regression Results for Pedestrian Crash Models—Analysis Model 7 ..........................90 Table 42. Contrast Results for Pedestrian Models—Analysis Model 7 ........................................90 Table 43. Yearly Pedestrian Crash Predictions—Analysis Model 7 .............................................91 iv

Author Acknowledgements The research reported herein was performed under NCHRP Project 3-89 by MRIGlobal. MRIGlobal was the contractor for this study, with Kittelson and Associates, and Ms. Janet M. Barlow, Accessible Design for the Blind, serving as subcontractors. Ms. Ingrid B. Potts, P.E., Principal Traffic Engineer at MRIGlobal, was the Principal Investigator for the research. The other authors of this report include Mr. Douglas W. Harwood, Ms. Karin M. Bauer, Mr. David K. Gilmore, Ms. Jessica M. Hutton, and Dr. Darren J. Torbic, MRIGlobal; Mr. John F. Ringert and Mr. Andrew Daleiden, Kittelson and Associates; and Ms. Janet M. Barlow, Accessible Design for the Blind. The work was done under the general supervision of Mr. Douglas W. Harwood, MRIGlobal’s Transportation Research Center Director. v

Abstract This report documents and presents the results of research to develop design guidance for channelized right-turn lanes. Observational field studies were conducted at 35 intersection approaches in cities to assess pedestrian crossing behavior, motorist yield behavior, and the interaction between pedestrians and motor vehicles at channelized right-turn lanes. Simulation modeling was performed to quantify the traffic operational benefits of channelized right-turn lanes with various types of traffic control and to compare the delay reduction of channelized right-turn lanes and conventional right-turn lanes. Crash data for nearly 400 intersection approaches in Toronto, Ontario, Canada, including intersection approaches with channelized right-turn lanes, conventional right-turn lanes, and shared through/right-turn lanes, were analyzed to compare the safety performance of the three right-turn treatment types. The research results indicate that channelized right-turn lanes have a definite role in improving operations and safety at intersections. However, to achieve these benefits they should have consistent design and traffic control and should be used at appropriate locations. The research provides design guidance for channelized right-turn lanes that addresses geometric elements such as crosswalk location, special crosswalk signing and marking, island type, radius of turning roadway, angle of intersection with cross street, acceleration and deceleration lanes, and traffic control. vi

Executive Summary Many transportation agencies use channelized right-turn lanes to improve operations at intersections, although their impact on safety for motorists, pedestrians, and bicyclists has not been clear in the past. A key concern with channelized right-turn lanes has been the extent of conflicts between vehicles and pedestrians that occur at the point where pedestrians cross the right-turn roadway. For most pedestrians, crossing the right-turn roadway is a relatively easy task because such roadways are not very wide and because traffic is approaching from a single direction. However, pedestrians with vision impairment may have difficulty detecting approaching traffic because (a) right-turning vehicles are traveling a curved rather than a straight path; (b) there is not a systematic stopping and starting of traffic, as there would be at a conventional signal- or stop- controlled intersection; and (c) the traffic sounds from the major streets may mask the sound of traffic on the right-turn roadway. Despite their potential challenges for pedestrians, channelized right-turn lanes also provide advantages for pedestrians. The provision of a channelized right- turn lane, while making it necessary for pedestrians to cross two roadways, often reduces the pedestrian crossing distance of the major and cross streets. Furthermore, the channelizing island, particularly when bounded by raised curbs, serves as a refuge area for pedestrians, and may improve safety by allowing pedestrians to cross the street in two stages. The primary traffic operational reasons for providing channelized right-turn lanes are to increase vehicular capacity at an intersection and to reduce delay to drivers by allowing them to turn at higher speeds and reduce unnecessary stops. Channelized right-turn lanes appear to provide a net reduction in motor vehicle delay at intersections where they are installed, although no existing data and no established methodology have been available to directly compare the operational performance of urban intersections with and without channelized right-turn lanes. The safety effects of channelized right-turn lanes on motor vehicles, pedestrians, and bicyclists have been largely unknown. It is generally accepted that channelized right-turn lanes improve safety for motor vehicles at intersections where they are used, but there have been only limited quantitative data to demonstrate this. No studies have been found concerning pedestrian safety at channelized right-turn lanes that have used crash data to document the pedestrian safety implications of channelized right-turn lanes. There also appears to be an inherent risk to bicyclists at channelized right-turn lanes because motor vehicles entering the channelized right- turn roadway must weave across the path of bicycles traveling straight through the intersection, but no studies based on crash history are available to support this presumption. However, a similar conflict between through bicyclists and right-turn vehicles is present at conventional intersections as well. It is evident that there have been many unanswered questions about channelized right-turn lanes. The research conducted for this report sought to answer many of these questions and to provide a basis for decisions, based on sound research results rather than anecdotal evidence, about where channelized right-turn lanes should and should not be used. The objective of the research was to develop design guidance for channelized right-turn lanes, based on balancing the needs of motor vehicles, pedestrians, and bicycles. Key studies in the research included field vii

observational studies of vehicle and pedestrian interactions at channelized right-turn lanes, interviews with orientation and mobility (O&M) specialists, traffic operational analyses of channelized right-turn lanes conducted with the VISSIM model, and safety analyses of channelized right-turn lanes. Observational field studies were conducted at 35 intersection approaches with channelized right-turn lanes in 11 cities to assess pedestrian crossing behavior, motorist yield behavior, and the interaction between pedestrians and motor vehicles at channelized right-turn lanes. A majority of the sites (nearly 70 percent) had marked crosswalks located near the center of the channelized right-turn lane; only about 30 percent of crosswalks were located at the upstream or downstream end of the channelized right-turn lane. Pedestrians did not appear to have any particular difficulty crossing channelized right-turn lanes. Most pedestrians crossed in the crosswalk (75 percent) and, where pedestrian signals were present, most pedestrians crossed during the pedestrian crossing phase (72 percent). The pedestrians who crossed outside the crosswalk generally did so when no vehicular traffic was present and this behavior did not cause any traffic conflicts. Avoidance maneuvers by a pedestrian or motorist appear to be relatively rare, and were observed in less than 1 percent of the pedestrian crossings. Most motorists yielded to pedestrians once they were in the crosswalk of a channelized right-turn lane, either by stopping or reducing their speed. Fewer motorists in channelized right- turn lanes yielded to pedestrians waiting at the curb to cross, although such failure to yield is typical of most pedestrian crossings and is not unique to channelized right-turn lanes. The yield behavior of motorists was slightly better at sites with special crosswalk treatments (e.g., raised crosswalk, pavement markings, signing). Interviews with ten orientation and mobility (O&M) specialists were conducted to learn of their experience in teaching pedestrians with vision impairment to traverse intersections with channelized right-turn lanes and to determine their recommendations on how channelized right- turn lanes might be better designed for all pedestrians with disabilities. O&M specialists did not have a definite preference for crosswalk location at channelized right-turn lanes, but recommended that consistency of crosswalk location and traffic control is important to pedestrians with vision impairment. They also had a strong preference for raised islands with “cut-through” pedestrian paths, which provide better guidance and information for pedestrians with vision impairment than painted islands. O&M specialists also indicated that channelized right-turn lanes with acceleration lanes were particularly challenging for pedestrians with vision impairment to cross. A traffic operational analysis was conducted to evaluate the traffic operational performance of right-turning vehicle movements at signalized intersections for three configurations: a conventional right-turn lane at a signalized intersection, a yield-controlled channelized right-turn lane, and a signalized channelized right-turn lane. A series of microscopic simulation runs (using VISSIM) were conducted to evaluate the traffic operational performance for both vehicles and pedestrians. The simulation studies addressed right-turn vehicle delay, delay due to pedestrian crossings, and the impact of intersection characteristics. viii