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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/24675.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/24675.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/24675.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/24675.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/24675.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/24675.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/24675.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/24675.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/24675.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/24675.
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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 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.

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NCHRP 3-78b: Final Project Report April 2016 TABLE OF CONTENTS 1 Introduction .................................................................................................................................................. 1 1.1 Research Objectives ................................................................................................................................ 2 1.2 Target Audience ...................................................................................................................................... 2 1.3 Organization of Final Report................................................................................................................... 3 2 Literature Review ......................................................................................................................................... 5 2.1 NCHRP Report 674 Framework for Accessible Crossings ..................................................................... 5 2.2 Overview of Previous Research with Blind Participants Regarding Actual Street Crossings and Judgments about When to Cross ...................................................................................................................... 6 2.3 Overview of Previous Research on Wayfinding by Blind Persons at Roundabouts and CTLs ............... 9 2.4 Overview of Research on Treatments to Reduce Crossing Risk for Blind Pedestrians ......................... 11 3 Methodology ................................................................................................................................................ 19 3.1 Data Collection Protocol ....................................................................................................................... 19 3.2 Site Selection ........................................................................................................................................ 22 3.3 Modeling Overview .............................................................................................................................. 38 3.4 IRB Approval ........................................................................................................................................ 39 4 Field Study Results ..................................................................................................................................... 41 4.1 Summary of Field Studies ..................................................................................................................... 41 4.2 Field Observations and Descriptive Data on Wayfinding ..................................................................... 52 5 Modeling and Applications ........................................................................................................................ 71 5.1 Free-Flow Speed Model ........................................................................................................................ 71 5.2 Crossing Sight Distance ........................................................................................................................ 73 5.3 Gap Opportunity Model ........................................................................................................................ 79 5.4 Yield Opportunity Model ...................................................................................................................... 82 5.5 Gap Utilization Model .......................................................................................................................... 85 5.6 Yield Utilization Model ........................................................................................................................ 86 5.7 Audible Environment and Noise Effects ............................................................................................... 87 5.8 Delay Model ......................................................................................................................................... 89 5.9 Risk Model............................................................................................................................................ 92 6 Conclusions.................................................................................................................................................. 95 6.1 Implications for Practice ....................................................................................................................... 95 6.2 Summary of Findings ............................................................................................................................ 96 6.3 Treatment Effects .................................................................................................................................. 99 6.4 Wayfinding ......................................................................................................................................... 100 6.5 Limitations and Future Research......................................................................................................... 101 7 Appendix A: Wayfinding Data Details .................................................................................................... 103 7.1 Introduction ......................................................................................................................................... 103 7.2 Method ................................................................................................................................................ 103 7.3 Results................................................................................................................................................. 106 8 Appendix B: Yield Model Details ............................................................................................................ 117 8.1 Introduction ......................................................................................................................................... 117 8.2 Methodology ....................................................................................................................................... 117 8.3 Results................................................................................................................................................. 119 8.4 Model Development ............................................................................................................................ 120 iii

NCHRP 3-78b: Final Project Report April 2016 iv 8.5 Summary ............................................................................................................................................. 123 9 Appendix C: Risk Model Details .............................................................................................................. 125 9.1 Methodology ....................................................................................................................................... 125 9.2 Results................................................................................................................................................. 126 9.3 Model Development ............................................................................................................................ 129 9.4 Summary ............................................................................................................................................. 135 11 Appendix D: Crossing Sight Distance Details ........................................................................................ 137 11.1 Introduction ......................................................................................................................................... 137 11.2 Methodology ....................................................................................................................................... 137 11.3 Data Collection ................................................................................................................................... 138 11.4 Data Analysis and Framework ............................................................................................................ 139 11.5 Summary ............................................................................................................................................. 146 11.6 Sight Distance Calculation Details ...................................................................................................... 147 11.7 Sight Distance Example Application .................................................................................................. 149 12 Appendix E: Site Photo Logs ................................................................................................................... 159 12.1 Tucson, AZ Photo Log ........................................................................................................................ 160 12.2 Boulder, CO Photo Log ...................................................................................................................... 179 12.3 Hilliard, OH Photo Log ...................................................................................................................... 205 12.4 Oakland County, MI Photo Log .......................................................................................................... 219 12.5 Ann Arbor, MI Photo Log .................................................................................................................. 234 12.6 Greenbelt, MD Photo Log ................................................................................................................... 252 12.7 Cary, NC Photo Log ........................................................................................................................... 267 12.8 CTL – SW corner of Tryon Road and Kildaire Farm Road ................................................................ 267 13 Appendix F: Detailed Field Study Results .............................................................................................. 277 LIST OF TABLES Table 2-1: Summary of Results Pedestrian Hybrid Beacon. (Schroeder et al., 2011a and RCOC 2011) ...................... 12 Table 2-2: Summary of Results RRFB. (RCOC 2011, FHWA TOPR34 Study) .......................................................... 13 Table 2-3: Summary of Results for Other Treatments. (Schroeder et al., 2011a and RCOC 2011) .............................. 14 Table 3-1: CTL Sites .................................................................................................................................................... 24 Table 3-2: Multi-Lane RBT Sites ................................................................................................................................. 25 Table 3-3: Single-Lane RBT Sites ................................................................................................................................ 26 Table 3-4: Listing of CTL Study Locations .................................................................................................................. 27 Table 3-5: Summary of Roundabout Study Locations ................................................................................................. 33 Table 3-6: Modeling Needs and Site Selection ............................................................................................................ 39 Table 5-1: Overview of Predictive Models................................................................................................................... 71 Table 5-2: Equivalent Composite Radius for Speed Estimation ................................................................................... 72 Table 5-3: Recommended Model to Predict Yielding Rates to Pedestrians .................................................................. 84 Table 5-4 Estimated Average Gap Utilization for Blind Pedestrians ............................................................................ 85 Table 5-5 Estimated Average Yield Utilization for Blind Pedestrians ......................................................................... 86 Table 5-6: Final Intervention Model ............................................................................................................................ 93 Table 7-1: Wayfinding Data Codes Based on Error Criterion .................................................................................... 105 Table 7-2: To Island Wayfinding Locations and Sample Sizes .................................................................................. 108 Table 7-3: On Island Wayfinding Locations and Sample Sizes .................................................................................. 111 Table 7-4: To Island Error Rates for Criterion 1, 3, and 5 at Roundabout Sites ......................................................... 113 Table 7-5: To Island Error Rates for Criterion 1, 3, and 5 at Channelized Turn Lane Sites ........................................ 114 Table 7-6: On Island Error Rates for Criterion 1 and 3 at Roundabout Sites .............................................................. 115 Table 7-7: On Island Error Rates for Criterion 1 and 3 at Channelized Turn Lane Sites ............................................ 116 Table 8-1: Variables of Interest in Yielding Study ..................................................................................................... 118 Table 8-2: Sample Sizes by State ............................................................................................................................... 118

NCHRP 3-78b: Final Project Report April 2016 v Table 8-3: Descriptive Statistics for Roundabout Sites .............................................................................................. 119 Table 8-4: Correlation Table for Roundabout Sites ................................................................................................... 120 Table 8-5: Full Model to Predict Yielding Rates to “Blind” and “Sighted” Pedestrians ............................................ 121 Table 8-6: Model Building Process for Geometric Yielding Model .......................................................................... 121 Table 8-7: Recommended Geometric Model to Predict Yielding Rates to “Blind” and “Sighted” Pedestrians ......... 122 Table 8-8: Model Building Process for Behavioral Yielding Model.......................................................................... 122 Table 8-9: Recommended Behavioral Model to Predict Yielding Rates to “Blind” and “Sighted” Pedestrians ......... 123 Table 8-10: Detailed Site Information for Yield Models ........................................................................................... 123 Table 9-1: Variables of Interest in Risk Modeling ..................................................................................................... 126 Table 9-2 Descriptive Statistics for Risk Modeling Variables ................................................................................... 126 Table 9-3 Correlation Table for Variables ................................................................................................................. 128 Table 9-4 Single Variable Models for Intervention and Intervention-Risky Models ................................................. 131 Table 9-5 Intervention Models ................................................................................................................................... 133 Table 9-6 Final Intervention Model ........................................................................................................................... 133 Table 9-7 Intervention-Risky Models ........................................................................................................................ 134 Table 9-8 Final Proposed Intervention-Risky Model ................................................................................................. 134 Table 11-1: Results of Sight Distance Calculation (Novi, MI) .................................................................................. 145 Table 11-2: Results of Sight Distance Calculation (Novi, MI) .................................................................................. 145 LIST OF FIGURES Figure 2-1: Blind pedestrian crossing at multi-lane roundabout .................................................................................... 7 Figure 2-2: Blind pedestrian attempting to cross at three-lane roundabout exit ............................................................. 8 Figure 3-1: CTL at Wilmont Road at Speedway Boulevard, Tucson, AZ ................................................................... 28 Figure 3-2: CTL at Sabino Canyon Road at Tanque Verde Road, Tucson, AZ ........................................................... 29 Figure 3-3: CTLs at Oracle Road and Grant Road, Tucson, AZ ................................................................................. 29 Figure 3-4: CTLs at 28th Street and Pearl, Boulder, CO .............................................................................................. 30 Figure 3-5: CTL at 28th Street and Canyon Boulevard, Boulder, CO .......................................................................... 31 Figure 3-6: CTL at Foothills Parkway and Arapahoe Avenue, Boulder, CO ............................................................... 31 Figure 3-7: CTL at Foothills Parkway and Baseline Road, Boulder, CO ..................................................................... 32 Figure 3-8: CTL at Kenilworth Avenue and East West Highway, Greenbelt, MD ...................................................... 32 Figure 3-9: CTL at Kildaire Farm Road and Tryon Road, Cary, NC ........................................................................... 33 Figure 3-10: Roundabout at Cemetery Road and Main Street, Hilliard, OH ............................................................... 34 Figure 3-11: Roundabout at Maple Road at Farmington Road, Oakland County, MI .................................................. 35 Figure 3-12: Roundabout at Cherrywood Lane at Metro Access Parkway, Greenbelt, MD ........................................ 36 Figure 3-13: Single-Lane Roundabout in Ann Arbor, MI with Milled Rumble Strips ................................................. 37 Figure 3-14: Two-Lane Roundabout with Milled Rumble Strips in Ann Arbor, MI ................................................... 37 Figure 3-15: Roundabout Site at Old Apex Road and West Chatham Street in Cary, NC ........................................... 38 Figure 4-1: Wilmont Road at Speedway Boulevard, NW Quadrant, Tucson, AZ ....................................................... 41 Figure 4-2: Sabino Canyon Road at Tanque Verde Road, NE Quadrant, Tucson, AZ ................................................ 42 Figure 4-3: Grant Road at Oracle Road, NE Quadrant, Tucson, AZ ............................................................................... 42 Figure 4-4: Grant Road at Oracle Road, SW Quadrant, Tucson, AZ ........................................................................... 43 Figure 4-5: 28th Street at Pearl Street, NE Quadrant, Boulder, CO ............................................................................. 43 Figure 4-6: 28th Street at Pearl Street, NW Quadrant, Boulder, CO ............................................................................ 44 Figure 4-7: 28th Street at Canyon Boulevard, SW Quadrant, Boulder, CO ................................................................. 44 Figure 4-8: Foothills Parkway at Arapahoe Avenue, SW Quadrant, Boulder, CO ...................................................... 45 Figure 4-9: Foothills Parkway at Baseline Drive, SW Quadrant, Boulder, CO ........................................................... 45 Figure 4-10: Foothills Parkway at Baseline Drive, NE Quadrant, Boulder, CO .......................................................... 46 Figure 4-11: Kenilworth Avenue at East West Highway, NW Quadrant, Greenbelt, MD ........................................... 46 Figure 4-12: Kildaire Farm Road at Tryon Road, SW Quadrant, Cary, NC ................................................................ 47 Figure 4-13: Main Street at Cemetery Road, East Approach, Hilliard, OH ................................................................. 48 Figure 4-14: Maple Road at Farmington Road, East Approach Exit, Oakland County, MI ......................................... 49 Figure 4-15: Maple Road at Farmington Road, South Approach Entry, Oakland County, MI .................................... 49 Figure 4-16: Greenbelt Metro Drive at Cherrywood Lane, West Entry and Exit Approaches, Greenbelt, MD ............ 50 Figure 4-17: Ellsworth Road at State Road, West Entry and Exit Approaches, Ann Arbor, MI .................................. 50

NCHRP 3-78b: Final Project Report April 2016 vi Figure 4-18: Nixon Road at Huron Parkway, South Exit and Entry Approaches, Ann Arbor, MI ............................... 51 Figure 4-19: Old Apex Road at West Chatham Street, West Entry and Exit Approaches, Cary, NC........................... 52 Figure 4-20: Grass between sidewalk and curb along edge of circulatory roadway between the crosswalks ............... 54 Figure 4-21: Gravel landscape strip provides detectable edge of sidewalk for person who is blind and separation between the sidewalk and CTL travel lane .................................................................................................................. 54 Figure 4-22: Gravel or grass outside the crosswalk and walkway area ........................................................................ 55 Figure 4-23: Pavers, with fairly rough texture (cobblestone) ..................................................................................... 56 Figure 4-24: Sidewalk at back of curb with no landscape separation .......................................................................... 56 Figure 4-25: Paved colored surfaces do not provide adequate cues ............................................................................. 57 Figure 4-26: Parallel ramp, showing curb at back of ramp .......................................................................................... 58 Figure 4-27: CTL with raised crosswalk and no detectable warning surfaces. Scored concrete is not detectable. ....... 59 Figure 4-28: View of raised crosswalk where some participants did not find detectable warnings ............................. 60 Figure 4-29: Roundabout without detectable surfaces or refuge in splitter islands ...................................................... 61 Figure 4-30: Approach direction, landscaping, returned curbs, detectable warning surface and crosswalk are all aligned, providing potential alignment cues for blind pedestrians ............................................................................... 63 Figure 4-31: Landscaping, curb ramp slope, detectable warning surface and gutter are not aligned with direction of travel on the crosswalk. This appeared to lead to alignment errors by blind pedestrians ............................................. 64 Figure 4-32: Ramp slope, detectable warning surface and gutter are all aligned to left of crosswalk direction ........... 64 Figure 4-33: At this location, some blind participants appeared to align themselves with the slope of the curb ramp and the line of the gutter, which led them to completely miss contacting the island .................................................... 65 Figure 4-34: Cut-through is narrower than the crosswalk ............................................................................................ 66 Figure 4-35: The APS pedestrian pushbutton on this island was not found by blind participants ................................ 68 Figure 5-1: Roundabout Vehicle Path Radii (Source: NCHRP Report 672) ................................................................ 72 Figure 5-2: Free-Flow Speed Model Validation with Field Data ................................................................................. 73 Figure 5-3: Minimum Sight Distance along the Actual Vehicle Path for Roundabouts............................................... 76 Figure 5-4: Pedestrian Sight Triangles for each Crossing Location (Sidewalk and crosswalks will be added to this figure) .......................................................................................................................................................................... 77 Figure 5-5: Minimum Sight Distance along the Actual Vehicle Path for CTLs .......................................................... 78 Figure 5-6: Sight Triangles Associated with Crossing Locations at CTLs .................................................................. 79 Figure 5-7: Gap Opportunity Validation for Roundabout Entry and Exit .................................................................... 81 Figure 5-8: Gap Opportunity Validation for Channelized Turn Lanes ........................................................................ 82 Figure 5-9: Graphical Representation of Yield Probability Model .............................................................................. 85 Figure 5-10: Graphical Presentation of Average Gap Utilization Rates ....................................................................... 86 Figure 5-11: Graphical Presentation of Average Yield Utilization Rates .................................................................... 87 Figure 5-12: Graphical Representation of CTL Delay Model ...................................................................................... 91 Figure 5-13: Graphical Representation of Single-Lane RBT Delay Model ................................................................. 91 Figure 5-14: Graphical Representation of Two-Lane RBT Delay Model .................................................................... 92 Figure 5-15: Plot of Predicted Intervention Rates vs. Observed Intervention Rates .................................................... 93 Figure 7-1: To Island Wayfinding Error Rates for All Roundabout and Channelized Turn Lane Sites ..................... 106 Figure 7-2: To Island Wayfinding Error Rates for Roundabout Sites ........................................................................ 107 Figure 7-3: To Island Wayfinding Error Rates for Channelized Turn Lane Sites ...................................................... 107 Figure 7-4: On Island Wayfinding Error Rates for All Roundabout and Channelized Turn Lane Sites ..................... 109 Figure 7-5: On Island Wayfinding Error Rates for Roundabout Sites ....................................................................... 110 Figure 7-6: On Island Wayfinding Error Rates for Channelized Turn Lane Sites ..................................................... 110 Figure 9-1 Plot of Predicted Intervention Rates vs. Observed Intervention Rates ...................................................... 135 Figure 9-2 Plot of Predicted Intervention-Risky Rates vs. Observed Intervention-Risky Rates ................................ 136 Figure 11-1: Pedestrian Sight Triangles for Each Crossing Location ........................................................................ 138 Figure 11-2: Minimum Sight Distance Along the Actual Path .................................................................................. 140 Figure 11-3: West Approach at Cemetery Road at Main Street, Hilliard, OH ........................................................... 141 Figure 11-4: West and East Approach at Cemetery Road at Main Street, Hilliard, OH ............................................ 142 Figure 11-5: Fastest Path Illustration (NCHRP 672) ................................................................................................. 143 Figure 11-6: Comparison Chart of All Three Approaches (RBT, Novi, MI) ............................................................. 146 Figure 12-1: Drivers’ view ........................................................................................................................................ 160 Figure 12-2: Pedestrian’s view .................................................................................................................................. 161 Figure 12-3: Raised crosswalk ................................................................................................................................... 161 Figure 12-4: Approach from south on sidewalk along Oracle (downstream street) ................................................... 162 Figure 12-5: Curb ramp ............................................................................................................................................. 162

NCHRP 3-78b: Final Project Report April 2016 vii Figure 12-6: Crosswalk view from the back of the ramp ........................................................................................... 163 Figure 12-7: Pedestrian path on island ....................................................................................................................... 163 Figure 12-8: Returned curb on edge of ramp ............................................................................................................. 164 Figure 12-9: Pushbutton alignment ............................................................................................................................ 164 Figure 12-10: Driver view of approach ...................................................................................................................... 165 Figure 12-11: Driver view of pedestrian at crosswalk ............................................................................................... 165 Figure 12-12: Pedestrian view of approach to crossing, along Grant ......................................................................... 166 Figure 12-13: Pedestrian approach along Oracle (from downstream end) ................................................................. 166 Figure 12-14: Lighting on the sidewalk ..................................................................................................................... 167 Figure 12-15: Pedestrian view of approaching vehicles in CTL ................................................................................ 167 Figure 12-16: Wide perpendicular ramp from curb to island ..................................................................................... 168 Figure 12-17: Edge of landscaping not aligned with edge of crosswalk or with crosswalk direction ........................ 168 Figure 12-18: Island pedestrian paths ........................................................................................................................ 169 Figure 12-19: Approach to channelized turn lane Driver and pedestrian's view ........................................................ 170 Figure 12-20: Crossing view from upstream (on left) and downstream (on right) ..................................................... 171 Figure 12-21: View of crosswalk ............................................................................................................................... 172 Figure 12-22: View of island ..................................................................................................................................... 172 Figure 12-23: Pushbuttons on island .......................................................................................................................... 173 Figure 12-24: View of crossing across Wilmot.......................................................................................................... 173 Figure 12-25: Reflectors on island ............................................................................................................................. 174 Figure 12-26: Approach view of CTL, sidewalk and crosswalk ............................................................................... 175 Figure 12-27: Yield signs at CTL .............................................................................................................................. 175 Figure 12-28: Combo curb ramp ................................................................................................................................ 176 Figure 12-29: Paths on island..................................................................................................................................... 176 Figure 12-30: Pushbutton location ............................................................................................................................. 177 Figure 12-31: Vehicular downstream lane merge ...................................................................................................... 178 Figure 12-32: Driver view on approach (SW corner) ............................................................................................... 179 Figure 12-33: Shared use path joins sidewalk ............................................................................................................ 180 Figure 12-34: Pedestrian's view on approach ............................................................................................................. 180 Figure 12-35: Closer view of crosswalk..................................................................................................................... 181 Figure 12-36: Sound strips ......................................................................................................................................... 181 Figure 12-37: Sound strips in deceleration lane ......................................................................................................... 182 Figure 12-38: Island ................................................................................................................................................... 182 Figure 12-39: Aligning to cross Baseline Road from island ...................................................................................... 183 Figure 12-40: Aligning to cross Foothills Parkway from island ................................................................................ 183 Figure 12-41: Pedestrian's view of approaching vehicles .......................................................................................... 183 Figure 12-42: Driver view on approach (NE corner) ................................................................................................. 184 Figure 12-43: Pedestrian view on approach ............................................................................................................... 184 Figure 12-44: View of crosswalk and island .............................................................................................................. 185 Figure 12-45: Narrow island crossing ........................................................................................................................ 185 Figure 12-46: Pushbutton to cross Foothills Parkway (road to right in photo)........................................................... 186 Figure 12-47: Aligning to cross Foothills Parkway ................................................................................................... 186 Figure 12-48: Aligning to cross Baseline Road ......................................................................................................... 187 Figure 12-49: Driver's approach to CTL along Arapahoe .......................................................................................... 188 Figure 12-50: Pedestrian view of approach to CTL ................................................................................................... 188 Figure 12-51: Pedestrian view from downstream sidewalk ....................................................................................... 189 Figure 12-52: Crosswalk view ................................................................................................................................... 189 Figure 12-53: View of crosswalk across Foothills Parkway ...................................................................................... 190 Figure 12-54: View of crosswalk across Arapahoe ................................................................................................... 190 Figure 12-55: Driver view on approach to 28th Street on Pearl ................................................................................. 191 Figure 12-56: Driver view of crosswalk (NE Corner 28th and Pearl) ........................................................................ 192 Figure 12-57: Pedestrian view on approach ............................................................................................................... 192 Figure 12-58: Pedestrian approach from downstream street ...................................................................................... 193 Figure 12-59: Gap between SW and curb .................................................................................................................. 193 Figure 12-60: View of downstream merge area ......................................................................................................... 194 Figure 12-61: View of crosswalk and island .............................................................................................................. 194 Figure 12-62: Crosswalk across 28th Street from island ........................................................................................... 195

NCHRP 3-78b: Final Project Report April 2016 viii Figure 12-63: Crosswalk across Pearl Street from island .......................................................................................... 195 Figure 12-64: View of island surface ......................................................................................................................... 196 Figure 12-65: Drivers' view on approach, northwest corner ...................................................................................... 197 Figure 12-66: Closer view of crosswalk..................................................................................................................... 197 Figure 12-67: Pedestrian approach to crosswalk ........................................................................................................ 198 Figure 12-68: Photo showing slope, for vehicles, of raised crosswalk ...................................................................... 198 Figure 12-69: View across crosswalk and island ....................................................................................................... 199 Figure 12-70: Crosswalk across Pearl Street on west side ......................................................................................... 200 Figure 12-71: Crosswalk across 28th Street............................................................................................................... 200 Figure 12-72: Driver's view of approach to crosswalk ............................................................................................... 201 Figure 12-73: Driver's view of crosswalk when approaching .................................................................................... 201 Figure 12-74: Pedestrian approach to crosswalk along Pearl ..................................................................................... 202 Figure 12-75: Pedestrian and driver view from close to crosswalk ............................................................................ 202 Figure 12-76: View of crosswalk from downstream end of CTL .............................................................................. 203 Figure 12-77: Pedestrian view across crosswalk and island ....................................................................................... 203 Figure 12-78: Crosswalk across 28th Street............................................................................................................... 204 Figure 12-79: Crosswalk across Canyon Blvd ........................................................................................................... 204 Figure 12-80: Approach from south (looking north) ................................................................................................. 205 Figure 12-81: Signs on approach from south ............................................................................................................. 205 Figure 12-82: View of roundabout from south median, at north pedestrian crosswalk for Scioto Darby Road roundabout. ................................................................................................................................................................ 206 Figure 12-83: Driveways close to roundabout ........................................................................................................... 206 Figure 12-84: “To both lanes in roundabout” plaque added below YIELD sign on all approaches ........................... 207 Figure 12-85: Red reflective sheeting was added on posts of some YIELD signs ..................................................... 207 Figure 12-86: Rough "cobblestone" surface used to separate sidewalk and roadway ................................................ 208 Figure 12-87: Overhead school crossing flashers ...................................................................................................... 208 Figure 12-88: Yield signs and markings at crosswalk................................................................................................ 209 Figure 12-89: R1-6 used as post mounted signs on splitter islands ............................................................................ 209 Figure 12-90: Lane drop just past roundabout ........................................................................................................... 210 Figure 12-91: Crosswalk for exit set back from circulatory roadway (east crosswalk) ............................................. 210 Figure 12-92: Zig-zag cut-through of island ............................................................................................................. 211 Figure 12-93: Island cut-through edge is aligned with crosswalk (photo at north crosswalk) ................................... 211 Figure 12-94: Ramp is generally aligned with crosswalk ......................................................................................... 212 Figure 12-95: Narrow splitter islands on west and south approaches ........................................................................ 212 Figure 12-96: View of roundabout when approaching from east ............................................................................... 213 Figure 12-97: Signs on east approach ........................................................................................................................ 213 Figure 12-98: Pavement markings within roundabout, and directional signs on splitter island.................................. 213 Figure 12-99: Flashers and markings in advance of crosswalk .................................................................................. 214 Figure 12-100: Control box extended into crosswalk approach area at head height for pedestrians who are blind. …214 Figure 12-101: North crosswalk exit lane crossing .................................................................................................... 215 Figure 12-102: Island decorative elements ................................................................................................................ 215 Figure 12-103: Sidewalk dip near crosswalk was confusing to some blind participants ............................................ 216 Figure 12-104: Zig-zag island at north crosswalk (used for wayfinding trials) .......................................................... 216 Figure 12-105: Roundabout sign on north and west approaches ................................................................................ 217 Figure 12-106: West crosswalk .................................................................................................................................. 217 Figure 12-107: Narrower island on west approach .................................................................................................... 218 Figure 12-108: Children crossing............................................................................................................................... 218 Figure 12-109: South leg, directional sign on approach ............................................................................................. 219 Figure 12-110: Driver's view on approach ................................................................................................................. 219 Figure 12-111: Driver's view - closer to crosswalk ................................................................................................... 220 Figure 12-112: Driver’s view of raised crosswalk from 100 feet back ....................................................................... 220 Figure 12-113: Pedestrian view of approach .............................................................................................................. 221 Figure 12-114: Grass landscaping on both sides of wide sidewalk ............................................................................ 221 Figure 12-115: Different ramp configurations ........................................................................................................... 222 Figure 12-116: View of temporary speed humps installed as raised crosswalks ....................................................... 222 Figure 12-117: Pedestrian view of crosswalk: south crosswalk ................................................................................. 223 Figure 12-118: RRFB mounted too low..................................................................................................................... 224

NCHRP 3-78b: Final Project Report April 2016 ix Figure 12-119: Island, lining up to cross exit lanes; south crosswalk ........................................................................ 224 Figure 12-120: South crosswalk exit lane; used for wayfinding trials ....................................................................... 225 Figure 12-121: Island, alignment of crossing for entry lanes, south crosswalk ......................................................... 225 Figure 12-122: Crossing exit lanes, east crosswalk.................................................................................................... 226 Figure 12-123: East crosswalk - merging traffic as road narrows from three lanes to one lane just past crosswalk .. 226 Figure 12-124: Pedestrian view of east crosswalk (looking north) ............................................................................ 227 Figure 12-125: Signage and markings on approach from east ................................................................................... 228 Figure 12-126: East leg - three-lane entry, closer view ............................................................................................. 228 Figure 12-127: Sidewalk on east leg, north side ........................................................................................................ 229 Figure 12-128: View of east entry leg pedestrian crosswalk ...................................................................................... 229 Figure 12-129: View of raised crosswalk .................................................................................................................. 230 Figure 12-130: Pedestrian approach to north crosswalk ............................................................................................ 230 Figure 12-131: View of north crosswalk .................................................................................................................... 231 Figure 12-132: Close-up view of audible information device .................................................................................... 231 Figure 12-133: North crosswalk and island pedestrian view ..................................................................................... 232 Figure 12-134: View of north crosswalk, from west, showing narrow splitter island ................................................ 232 Figure 12-135: View of west crosswalk ..................................................................................................................... 233 Figure 12-136: Lane pavement markings within circle .............................................................................................. 233 Figure 12-137: East leg exit lane crossing ................................................................................................................. 234 Figure 12-138: Approach to roundabout, looking west from east leg ........................................................................ 234 Figure 12-139: Drivers’ view of crosswalk................................................................................................................ 235 Figure 12-140: View of zig-zag cut-through island ................................................................................................... 235 Figure 12-141: Rumble strips in pavement ................................................................................................................ 236 Figure 12-142: Entry east leg ..................................................................................................................................... 236 Figure 12-143: View of curb and detectable warning surface and alignment of sidewalk at east entry ..................... 237 Figure 12-144: Looking back at entry rumble strips and lane markings .................................................................... 237 Figure 12-145: View of north crosswalk exit lanes .................................................................................................... 238 Figure 12-146: View of rumble strips and distance before crosswalk ........................................................................ 238 Figure 12-147: View of another zig-zag cut-through island ...................................................................................... 239 Figure 12-148: North crosswalk, crossing exclusive right turn ................................................................................. 239 Figure 12-149: Exit lanes – west crosswalk (studied) ................................................................................................ 240 Figure 12-150: Another view of exit lane crosswalk and splitter island .................................................................... 240 Figure 12-151: Pedestrian view of west crosswalk exit lane crossing ....................................................................... 241 Figure 12-152: Bike ramp and sidewalk view ............................................................................................................ 241 Figure 12-153: Entry lane crosswalk from island west leg ........................................................................................ 242 Figure 12-154: Pedestrian view of entry leg crossing West crosswalk ...................................................................... 242 Figure 12-155:View of overhead crosswalk signs ..................................................................................................... 243 Figure 12-156: View of ramp to crosswalk at exit lane with bike ramp in background ............................................. 243 Figure 12-157: View of crosswalk studied, sidewalk and landscaping ...................................................................... 244 Figure 12-158: Closer view of bike ramp .................................................................................................................. 244 Figure 12-159: Small diameter circle ......................................................................................................................... 245 Figure 12-160: Driver’s view of exit crosswalk – south leg ...................................................................................... 245 Figure 12-161: Yield signs......................................................................................................................................... 246 Figure 12-162: West crosswalk .................................................................................................................................. 246 Figure 12-163: View of crosswalk lighting (west crosswalk) .................................................................................... 247 Figure 12-164: Pedestrian view of crosswalk approach west leg ............................................................................... 247 Figure 12-165: Narrow splitter island ........................................................................................................................ 248 Figure 12-166: Truck apron at entry .......................................................................................................................... 249 Figure 12-167: North crosswalk ................................................................................................................................ 249 Figure 12-168: View of east crosswalk ...................................................................................................................... 250 Figure 12-169: East crosswalk splitter island............................................................................................................. 250 Figure 12-170: East crosswalk splitter island ............................................................................................................. 251 Figure 12-171: Bike ramp on entry ............................................................................................................................ 251 Figure 12-172: Driver’s view on approach on west leg (Cherrywood) ...................................................................... 252 Figure 12-173: Bike sign and ramp to sidewalk......................................................................................................... 253 Figure 12-174: Markings and signs at entry ............................................................................................................... 254 Figure 12-175: Pedestrian view on approach ............................................................................................................. 254

NCHRP 3-78b: Final Project Report April 2016 x . Figure 12-176: Narrow entry to curb ramp and crosswalk ......................................................................................... 255 Figure 12-177: View of pedestrian crosswalk – west crosswalk across Cherrywood looking north .......................... 255 Figure 12-178: Uneven pavement near beginning of west crosswalk, from south ..................................................... 256 Figure 12-179: View of west leg (leaving roundabout) looking west from crosswalk on north side of Cherrywood Lane ........................................................................................................................................................................... 256 Figure 12-180: Parallel curb ramp on north side (exit lanes) of west crosswalk ........................................................ 257 Figure 12-181: Approach from north ......................................................................................................................... 257 Figure 12-182: Crosswalk not far from yield line/sign for vehicles entering roundabout from north ........................ 258 Figure 12-183: Median between lanes ....................................................................................................................... 258 Figure 12-184: Another view of median and crosswalk (north crossing)................................................................... 259 Figure 12-185: View of crosswalk north crossing ..................................................................................................... 259 Figure 12-186: View of exit lane crosswalk on west leg from north leg (from median between right only lane and right/through lane) ..................................................................................................................................................... 260 Figure 12-187: East approach .................................................................................................................................... 260 Figure 12-188: View from crosswalk of vehicles approaching from east let to north leg .......................................... 261 Figure 12-189: Narrowed sidewalk along south side of roundabout .......................................................................... 261 Figure 12-190: Approach to intersection ................................................................................................................... 262 Figure 12-191: Unusual placard under pedestrian warning sign; ACROSS RAMP .................................................. 262 Figure 12-192: View of crosswalk location ............................................................................................................... 263 Figure 12-193: Pedestrian's view on approach ........................................................................................................... 263 Figure 12-194: Pedestrian's view of approaching traffic from crosswalk .................................................................. 264 Figure 12-195: View of crosswalk and island ............................................................................................................ 264 Figure 12-196: Detectable warning on island at entry to cut-through area covered in dirt and debris ....................... 265 Figure 12-197: Crossing East West Highway from island ......................................................................................... 265 Figure 12-198: Crossing Kenilworth Road from island ............................................................................................. 266 Figure 12-199: Driver's view on approach on Tryon Road ........................................................................................ 267 Figure 12-200: Signal ahead sign ............................................................................................................................... 267 Figure 12-201: Driver’s view of CTL and pedestrian crossing .................................................................................. 268 Figure 12-202: Marked crosswalk is not very visible on approach ............................................................................ 268 Figure 12-203: Pedestrian approach .......................................................................................................................... 269 Figure 12-204: Crosswalk approach sidewalk ........................................................................................................... 269 Figure 12-205: Crosswalk across right turn lane and view of large island area ......................................................... 270 Figure 12-206: Curb ramps and crosswalks for Tryon (front) and Kildaire Farm (to right) ....................................... 271 Figure 12-207: Closer view of curb ramps ................................................................................................................. 271 Figure 12-208: Driver's view of roundabout on approach from west on Old Apex Road .......................................... 272 Figure 12-209: Pedestrian approach to west crosswalk, entry leg ............................................................................. 272 Figure 12-210: West crosswalk, from south end ........................................................................................................ 273 Figure 12-211: View of west exit crosswalk from beyond east crosswalk ................................................................. 274 Figure 12-212: Pedestrian approach to west crosswalk, exit lane .............................................................................. 274 Figure 12-213: West crosswalk, looking south, exit lane crossing............................................................................. 275 Figure 12-214: Illustration of pedestrian stepping past detectable warning surface that doesn't extend the full width of the cut-through in island ........................................................................................................................................ 275

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Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities Get This Book
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TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 222: Guidelines for the Application of Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities provides guidance to engineers and planners on the design of roundabouts and channelized turn lanes for accessibility. NCHRP Web-Only Document 222 is the final report for NCHRP Research Report 834: Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities: A Guidebook.

The accessibility of modern roundabouts and intersections with channelized turn lanes is an important civil rights challenge in the United States that has broad potential implications for engineering practice in this country. This report builds on the results of NCHRP Report 674: Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians with Vision Disabilities. It provides a framework for empirical study and analysis of accessibility performance, documents field testing of several treatments, and provides a research extension through modeling and simulation to expand the results beyond the field-tested sites.

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