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NCHRP Web-Only Document 256: Assessing Interactions Between Access Management Treatments and Multimodal Users Marc Butorac James Bonneson Kristine Connolly Paul Ryus Bastian Schroeder Kittelson & Associates, Inc. Portland, OR Kristine Williams Zhenyu Wang Seckin Ozkul Center for Urban Transportation Research University of South Florida Tampa, FL Jerome Gluck AECOM, Inc. New York, NY Contractorâs Final Report for NCHRP Project 03-120 Submitted July 2018 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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CÂ OÂ OÂ PÂ EÂ RÂ AÂ TÂ IÂ VÂ EÂ RÂ EÂ SÂ EÂ AÂ RÂ CÂ HÂ PÂ RÂ OÂ GÂ RÂ AÂ MÂ SÂ CRP STAFF FOR NCHRP Web-Only Document 256 Christopher J. Hedges, Director, Cooperative Research Programs Lori L. Sundstrom, Deputy Director, Cooperative Research Programs Waseem Dekelbab, Senior Program Officer Megan A. Chamberlain, Senior Program Assistant Eileen P. Delaney, Director of Publications Natalie Barnes, Associate Director of Publications Kathleen Mion, Senior Editorial Assistant NCHRP PROJECT 03-120 PANEL Field of Administration: TRAFFICâOPERATIONS AND CONTROL James L. Gattis, University of Arkansas, Springfield, MO (Chair) Barbara J. De Saint Croix, Washington State DOT, Olympia, WA Gina Bonyani, Florida DOT, Tallahassee, FL Philip B. Demosthenes, Philip B.Demosthenes LLC, Denver, CO Robert Dunphy, Arlington, VA Brian K. Gage, Minnesota DOT, St Paul, MN Alan Ginder, The Port Authority of New York and New Jersey, New York, NY Chris W. Huffman, Huffman Corridor Consulting, LLC, Topeka, KS Jean Lionel Lucien, Massachusetts DOT, Boston, MA Jeffrey B. Shaw, FHWA Liaison Richard A. Cunard, TRB Liaison AUTHOR ACKNOWLEDGMENTS The research reported herein was performed under NCHRP Project 03-120. Kittelson & Associates, Inc. (KAI) was the contractor for this study. The Center for Urban Transportation Research, University of South Florida (CUTR) and AECOM, Inc. were subcontractors. Authors of this report are Marc Butorac (KAI), James Bonneson (KAI), Kristine Connolly (KAI), Paul Ryus (KAI), Bastian Schroeder (KAI), Seckin Ozkul (CUTR), Zhenyu Wang (CUTR), Kristine Williams (CUTR), and Jerome Gluck (AECOM). Mr. Butorac served as the Principal Investigator for this project. The authors wish to acknowledge the assistance and support of key staff members for their significant contributions to the data collection and traffic simulation tasks. The KAI staff members include: Elizabeth Connell, Chelsea Farnsworth, Ellen Moshier, Clarissa Dougherty, Miranda Barrus, and Lake Trask. The CUTR graduate research assistants and staff members include: Dharmin Kukadia, Teerapat Charukitpaisarn, Abhijit Vasili, Rama Durga Tammayya Naidu Kolla, and Ashok Sampath. The AECOM staff members include: Jacquilyn Coelho, Gabriel Kleinfeld, Jeffrey Sandberg, and Chaithra Jagadish. The authors would also like to extend special thanks to the agency staff that provided assistance during the data collection tasks. These individuals include: Ping P. Hsu (Florida Department of Transportation, District 7), Richard Napora (Florida Department of Transportation, District 7), and Norman D. Jester (Pinellas County, Florida). The authors also acknowledge Li Zhang and Xiang Li from New Global Systems for their technical support in implementation of the Surrogate Safety Assessment Model (SSAM) version 3.0. The authors wish to express sincere thanks to the members of the project panel, who provided extremely helpful guidance and feedback on the many documents they were asked to review.
v Contents Chapter 1: Background .......................................................................................................................... 1Â Research Objective ............................................................................................................................... 1Â Research Scope ..................................................................................................................................... 1Â Research Plan ........................................................................................................................................ 3Â Chapter 2: State of the Practice ............................................................................................................. 5Â Introduction ........................................................................................................................................... 5Â Literature Review .................................................................................................................................. 5Â Agency Survey .................................................................................................................................... 11Â References ........................................................................................................................................... 14Â Chapter 3: Research Approach ........................................................................................................... 15Â Introduction ......................................................................................................................................... 15Â Assessment of Data and Information Needs ....................................................................................... 16Â Overview of Initial Study Designs ...................................................................................................... 21Â Overview of Final Study Designs ....................................................................................................... 27Â References ........................................................................................................................................... 32Â Chapter 4: Findings and Applications ................................................................................................ 34Â Introduction ......................................................................................................................................... 34Â Development of Performance Relationships ....................................................................................... 34Â Development of a Guide for the Analysis of Multimodal Corridor Access Management .................. 38Â References ........................................................................................................................................... 44Â Chapter 5: Conclusions and Suggested Research .............................................................................. 45Â Introduction ......................................................................................................................................... 45Â Conclusions ......................................................................................................................................... 45Â Suggested Research ............................................................................................................................. 48Â References ........................................................................................................................................... 49Â Appendix A: Literature Review ........................................................................................................... 50Â Introduction ......................................................................................................................................... 50Â Documents Reviewed.......................................................................................................................... 50Â Identified AM Techniques .................................................................................................................. 53Â Technique Effect on Performance of Selected Travel Modes ............................................................. 58Â References ........................................................................................................................................... 90Â Appendix B: Agency Survey ................................................................................................................ 94Â Introduction ......................................................................................................................................... 94Â Survey Instrument ............................................................................................................................... 94Â Survey Findings .................................................................................................................................. 96Â Appendix C: Assessment of Data and Information Needs .............................................................. 114Â Introduction ....................................................................................................................................... 114Â Stage 1 â Initial Selection of Techniques .......................................................................................... 114Â Stage 2 â Final Selection of Techniques ........................................................................................... 135Â Stage 3 â Detailed Assessment of Selected Techniques ................................................................... 142Â Assessment of Supplemental Techniques ......................................................................................... 143Â Final Assessment and Prioritization of Techniques .......................................................................... 146Â Appendix D: Initial Study Designs .................................................................................................... 150Â Introduction ....................................................................................................................................... 150Â Study Designs for Original Techniques ............................................................................................ 150Â
vi Study Designs for Supplemental Techniques .................................................................................... 190Â Appendix E: Final Study Designs ...................................................................................................... 196Â Introduction ....................................................................................................................................... 196Â Driveway Design ............................................................................................................................... 196Â Right-Turn Deceleration ................................................................................................................... 203Â TWLTL vs. Non-Traversable Median .............................................................................................. 209Â Simulation Model Calibration ........................................................................................................... 218Â References ......................................................................................................................................... 226Â Appendix F: Data Summary .............................................................................................................. 227Â Introduction ....................................................................................................................................... 227Â Driveway Design ............................................................................................................................... 227Â Right-Turn Deceleration ................................................................................................................... 238Â TWLTL vs. Non-Traversable Median .............................................................................................. 249Â VISSIM Simulation Model Calibration ............................................................................................ 262Â SSAM Simulation Model Calibration ............................................................................................... 277Â References ......................................................................................................................................... 282Â Appendix G: Performance Relationship Development .................................................................... 283Â Introduction ....................................................................................................................................... 283Â Right-Turn Deceleration ................................................................................................................... 283Â TWLTL vs. Non-Traversable Median .............................................................................................. 308Â References ......................................................................................................................................... 368Â
vii List of Figures Figure 1. Distribution of respondents. ........................................................................................................ 97Â Figure 2. Access management treatments implemented. ............................................................................ 98Â Figure 3. Measures of effectiveness for evaluating the effects of access management treatments on non- auto modes. ............................................................................................................................................... 107Â Figure 4. Access management treatments needing additional analysis relative to non-auto modes. ........ 110Â Figure 5. Intersection boundaries â driveway design................................................................................ 197Â Figure 6. Camera location at driveway study site â driveway design. ...................................................... 201Â Figure 7. Camera locations along urban street for simulation calibration â VISSIM calibration. ............ 222Â Figure 8. Camera location for intersection data collection â VISSIM calibration. ................................... 223Â Figure 9. Camera location for driveway data collection â VISSIM calibration. ...................................... 223Â Figure 10. Plan view of intersection test bed for travel time measurement â right-turn deceleration. ..... 241Â Figure 11. Measurement boundary for safety evaluation - right-turn deceleration................................... 247Â Figure 12. Evaluation segment test beds â TWLTL vs. non-traversable median. .................................... 252Â Figure 13. Segment boundaries â TWLTL vs. non-traversable median. .................................................. 258Â Figure 14. Plan view sketch of cameras and counters at three segment test beds â VISSIM calibration. 267Â Figure 15. Plan view sketch of cameras at two intersection test beds â VISSIM calibration. .................. 268Â Figure 16. Plan view of simulated street system at three segment test beds â VISSIM calibration. ........ 272Â Figure 17. Plan view of simulated street system at two intersection test beds â VISSIM calibration. ..... 272Â Figure 18. Relative difference between observed and simulated travel time â VISSIM calibration. ....... 275Â Figure 19. Simulated saturation flow rate â VISSIM calibration. ............................................................ 277Â Figure 20. Predicted vs. observed bicycle delay â right-turn deceleration. .............................................. 287Â Figure 21. Influence of various factors on bicycle delay â right-turn deceleration. ................................. 288Â Figure 22. Predicted vs. observed transit vehicle delay â right-turn deceleration. ................................... 290Â Figure 23. Influence of various factors on transit-vehicle delay â right-turn deceleration. ...................... 291Â Figure 24. Predicted vs. observed truck vehicle delay â right-turn deceleration. ..................................... 293Â Figure 25. Influence of various factors on truck delay â right-turn deceleration. ..................................... 294Â Figure 26. Relationship between hourly conflict frequency and average annual crash frequency â right- turn deceleration. ....................................................................................................................................... 296Â Figure 27. Relationship between daily conflict frequency and average annual crash frequency â right-turn deceleration. .............................................................................................................................................. 298Â Figure 28. Predicted vs. observed transit-related conflict frequency â right-turn deceleration. ............... 302Â Figure 29. Influence of various factors on transit-related conflicts â right-turn deceleration. .................. 303Â Figure 30. Right-turn deceleration lane length CMF, transit-related conflicts â right-turn deceleration. 304Â Figure 31. Predicted vs. observed truck-related conflict frequency â right-turn deceleration. ................. 306Â Figure 32. Influence of various factors on truck-related conflicts â right-turn deceleration. ................... 307Â Figure 33. Right-turn deceleration lane length CMF, truck-related conflicts â right-turn deceleration. .. 308Â Figure 34. Predicted vs. observed bicycle speed for TWLTL â TWLTL vs. non-traversable median. .... 312Â Figure 35. Influence of various factors on bicycle speed for TWLTL â TWLTL vs. non-traversable median. ...................................................................................................................................................... 313Â Figure 36. Predicted vs. observed bicycle speed for non-traversable median â TWLTL vs. non-traversable median. ...................................................................................................................................................... 314Â Figure 37. Influence of various factors on bicycle speed for non-traversable median â TWLTL vs. non- traversable median. ................................................................................................................................... 315Â Figure 38. Predicted vs. observed truck speed for TWLTL â TWLTL vs. non-traversable median. ....... 317Â Figure 39. Influence of various factors on truck speed for TWLTL â TWLTL vs. non-traversable median. .................................................................................................................................................................. 318Â
viii Figure 40. Predicted vs. observed truck speed for non-traversable median â TWLTL vs. non-traversable median. ...................................................................................................................................................... 320Â Figure 41. Influence of various factors on truck speed for non-traversable median â TWLTL vs. non- traversable median. ................................................................................................................................... 321Â Figure 42. Examination of lane width and crash rate â TWLTL vs. non-traversable median. ................. 323Â Figure 43. Examination of median width and crash rate â TWLTL vs. non-traversable median. ............ 324Â Figure 44. Examination of average outside shoulder width plus bike lane width and crash rate â TWLTL vs. non-traversable median. ...................................................................................................................... 325Â Figure 45. Examination of commercial driveway density and crash rate â TWLTL vs. non-traversable median. ...................................................................................................................................................... 325Â Figure 46. Examination of partial-access driveway presence and crash rate â TWLTL vs. non-traversable median. ...................................................................................................................................................... 326Â Figure 47. Examination of public street approach density and crash rate â TWLTL vs. non-traversable median. ...................................................................................................................................................... 327Â Figure 48. Predicted transit-related crash frequency, TM segments â TWLTL vs. non-traversable median. .................................................................................................................................................................. 335Â Figure 49. Predicted vs. reported transit-related crash frequency, TM segments â TWLTL vs. non- traversable median. ................................................................................................................................... 335Â Figure 50. Predicted transit-related crash frequency, NTM segments â TWLTL vs. non-traversable median. ...................................................................................................................................................... 337Â Figure 51. Predicted vs. reported transit-related crash frequency, NTM segments â TWLTL vs. non- traversable median. ................................................................................................................................... 337Â Figure 52. Lane and shoulder width CMF, transit-related crashes, both median types â TWLTL vs. non- traversable median. ................................................................................................................................... 338Â Figure 53. Median width CMF, transit-related crashes, non-traversable median type â TWLTL vs. non- traversable median. ................................................................................................................................... 339Â Figure 54. Access point CMF, transit-related crashes, both median types â TWLTL vs. non-traversable median. ...................................................................................................................................................... 340Â Figure 55. Predicted truck-related crash frequency, TM segments â TWLTL vs. non-traversable median. .................................................................................................................................................................. 346Â Figure 56. Predicted vs. reported truck-related crash frequency, TM segments â TWLTL vs. non- traversable median. ................................................................................................................................... 346Â Figure 57. Predicted truck-related crash frequency, NTM segments â TWLTL vs. non-traversable median. .................................................................................................................................................................. 347Â Figure 58. Predicted vs. reported truck-related crash frequency, NTM segments â TWLTL vs. non- traversable median. ................................................................................................................................... 348Â Figure 59. Lane width CMF, truck-related crashes, both median types â TWLTL vs. non-traversable median. ...................................................................................................................................................... 349Â Figure 60. Shoulder width CMF, truck-related crashes, both median types â TWLTL vs. non-traversable median. ...................................................................................................................................................... 350Â Figure 61. Median width CMF, truck-related crashes, non-traversable median type â TWLTL vs. non- traversable median. ................................................................................................................................... 351Â Figure 62. Full access point CMF, truck-related crashes, both median types â TWLTL vs. non-traversable median. ...................................................................................................................................................... 352Â Figure 63. Partial access point CMF, truck-related crashes, both median types â TWLTL vs. non- traversable median. ................................................................................................................................... 353Â Figure 64. Lateral separation flexibility afforded by the traversable and non-traversable median â TWLTL vs. non-traversable median. ...................................................................................................................... 359Â
ix List of Tables Table 1. Researcherâs prioritized list of techniques to study in Phase 2. ................................................. xviii Table 2. Final prioritized list of techniques considered for study in Phase 2. ........................................... xix Table 3. Technique influence on operations and safety. ............................................................................... 6 Table 4. Techniques identified as candidates for further study during stage 2. .......................................... 16 Table 5. Researcherâs prioritized list of techniques to study in Phase 2. .................................................... 18 Table 6. Estimated utility and development cost for four supplemental techniques. .................................. 19 Table 7. Final prioritized list of techniques considered for study in Phase 2. ............................................ 20 Table 8. Study design worksheet. ............................................................................................................... 22 Table 9. Candidate performance measures. ................................................................................................ 27 Table 10. Final list of techniques for further study in Phase 2. .................................................................. 28 Table 11. Performance relationships to evaluate right-turn deceleration lane installation. ........................ 35 Table 12. Operations model variables â right-turn deceleration. ................................................................ 35 Table 13. Safety model variables â right-turn deceleration. ....................................................................... 36 Table 14. Performance relationships to evaluate TWLTL and non-traversable median installations. ....... 37 Table 15. Operations model variables â TWLTL vs. non-traversable median. .......................................... 37 Table 16. Safety model variables â TWLTL vs. non-traversable median. ................................................. 38 Table 17. Example performance summary tables from the Guide. ............................................................. 40 Table 18. Example trend table from the Guide for installing continuous TWLTLs. .................................. 41 Table 19. Quantitative method applicability by access management technique group............................... 43 Table 20. Techniques identified as candidates for future research. ............................................................ 48 Table 21. Relevant documents identified by the literature review. ............................................................. 51 Table 22. Documented effects on roadway travel modes by access management techniques. ................... 53 Table 23. Traffic signal spacing â operations. ............................................................................................ 59 Table 24. Traffic signal spacing â safety. ................................................................................................... 60 Table 25. Access point spacing â operations. ............................................................................................. 61 Table 26. Access point spacing â safety. .................................................................................................... 62 Table 27. Corner clearance â operations. .................................................................................................... 63 Table 28. Corner clearance â safety. ........................................................................................................... 63 Table 29. Non-traversable median â operations. ........................................................................................ 64 Table 30. Non-traversable median â safety. ............................................................................................... 65 Table 31. Median opening â operations. ..................................................................................................... 67 Table 32. Median opening â safety. ............................................................................................................ 67 Table 33. Median designed for left turns from the major roadway â operations. ....................................... 68 Table 34. Median designed for left turns from the major roadway â safety. .............................................. 69 Table 35. Two-way left-turn lane â operations. .......................................................................................... 70 Table 36. Two-way left-turn lane â safety. ................................................................................................. 71 Table 37. Median U-turns as an alternative to direct left turns â operations. ............................................. 72 Table 38. Median U-turns as an alternative to direct left turns â safety. .................................................... 73 Table 39. Right-turn deceleration lane â operations. .................................................................................. 74 Table 40. Right-turn deceleration lane â safety. ......................................................................................... 75 Table 41. Continuous right-turn lane â operations...................................................................................... 76 Table 42. Continuous right-turn lane â safety. ............................................................................................ 76 Table 43. Consolidate driveways â operations. .......................................................................................... 77 Table 44. Consolidate driveways â safety. ................................................................................................. 77Â
x Table 45. Driveway channelization to discourage or prohibit left turns â operations. ............................... 78Â Table 46. Driveway channelization to discourage or prohibit left turns â safety. ...................................... 79Â Table 47. Intersection spacing on interchange crossroad â operations. ...................................................... 80Â Table 48. Intersection spacing on interchange crossroad â safety. ............................................................. 81Â Table 49. Raised median barrier to discourage left turns â operations. ...................................................... 81Â Table 50. Raised median barrier to discourage left turns â safety. ............................................................. 82Â Table 51. Sidewalk-driveway crossing location â operations. .................................................................... 83Â Table 52. Sidewalk-driveway crossing location â safety. ........................................................................... 83Â Table 53. Prohibit major street driveway access â operations. ................................................................... 84Â Table 54. Prohibit major street driveway access â safety. .......................................................................... 84Â Table 55. Relocate or reorient access â operations. .................................................................................... 85Â Table 56. Relocate or reorient access â safety. ........................................................................................... 85Â Table 57. Remove curb parking â operations. ............................................................................................ 86Â Table 58. Remove curb parking â safety. ................................................................................................... 87Â Table 59. Roundabout â operations. ........................................................................................................... 88Â Table 60. Roundabout â safety. .................................................................................................................. 89Â Table 61. Driveway sight distance â operations. ........................................................................................ 89Â Table 62. Driveway sight distance â safety. ............................................................................................... 90Â Table 63. Treatments identified by 15% or more of respondents as adversely impacting safety of non-auto modes. ......................................................................................................................................................... 99Â Table 64. Treatments identified by 15% or more of respondents as adversely impacting operation of non- auto modes. ................................................................................................................................................. 99Â Table 65. Treatments identified by 15% or more of respondents as positively impacting safety of non-auto modes. ....................................................................................................................................................... 104Â Table 66. Treatments identified by 15% or more of respondents as positively impacting operation of non- auto modes. ............................................................................................................................................... 105Â Table 67. State transportation agency multimodal access management analysis priorities. ..................... 110Â Table 68. Consultant multimodal access management analysis priorities. ............................................... 111Â Table 69. University multimodal access management analysis priorities. ............................................... 111Â Table 70. Technique influence on operations and safety. ......................................................................... 115Â Table 71. Technique categories addressed in survey. ............................................................................... 120Â Table 72. Estimated utility and development cost by technique for Stage 1. ........................................... 125Â Table 73. Performance relationship development costs for techniques applied at âsiteâ scale. ............... 128Â Table 74. Top 20 AM Techniques selected in Stage 1. ............................................................................ 131Â Table 75. Survey responses regarding safety or operations impact of Technique 1a. .............................. 133Â Table 76. Updated information about technique influence on operations and safety. .............................. 136Â Table 77. Estimated utility and development cost by technique for Stage 2. ........................................... 140Â Table 78. Techniques selected in Stage 2. ................................................................................................ 142Â Table 79. Prioritized list of techniques to evaluate in Phase 2. ................................................................. 143Â Table 80. Information about influence of supplemental techniques on operations and safety. ................ 144Â Table 81. Estimated utility and development cost for four supplemental techniques. .............................. 145Â Table 82. Final list of techniques for further study in Phase 2. ................................................................ 147Â Table 83. Utility and development cost for final list of techniques. ........................................................ 148Â Table 84. Study design for traffic signal spacing. ..................................................................................... 151Â Table 85. Study design for access point spacing....................................................................................... 153Â Table 86. Study design for corner clearance. ............................................................................................ 155Â Table 87. Study design for non-traversable median.................................................................................. 157Â Table 88. Study design for closing existing median openings. ................................................................. 159Â
xi Table 89. Study design for replacing a full median opening with a median designed for left turns from the major roadway. ......................................................................................................................................... 161Â Table 90. Study design for installation of a continuous TWLTL on an undivided highway. ................... 163Â Table 91. Study design for median U-turns as an alternative to direct left turns. ..................................... 165Â Table 92. Study design for installation of a right-turn deceleration lane. ................................................. 167Â Table 93. Study design for installation of a continuous right-turn lane. ................................................... 169Â Table 94. Study design for consolidate driveways.................................................................................... 171Â Table 95. Study design for channelizing driveways to discourage or prohibit left turns. ......................... 173Â Table 96. Study design for intersection spacing on interchange crossroad. ............................................. 175Â Table 97. Study design for installation of median barrier with no direct left-turn ingress or egress. ....... 177Â Table 98. Study design for moving the sidewalk crossing of a driveway away from the roadway. ......... 179Â Table 99. Study design for requiring access on collector instead of a nearby highway. .......................... 181Â Table 100. Study design for relocation or reorientation of an access point. ............................................. 183Â Table 101. Study design for removing curb parking................................................................................. 185Â Table 102. Study design for installation of a roundabout. ........................................................................ 187Â Table 103. Study design for improve driveway sight distance. ................................................................ 189Â Table 104. Study design for driveway design. .......................................................................................... 191Â Table 105. Study design for TWLTL vs. non-traversable median. .......................................................... 193Â Table 106. Study design for corner clearance (revised). ........................................................................... 195Â Table 107. Performance relationships planned for development â driveway design. ............................... 197Â Table 108. Data elements possibly affecting performance â driveway design. ........................................ 198Â Table 109. Performance relationships planned for development â right-turn deceleration. ..................... 203Â Table 110. Data elements possibly affecting performance â right-turn deceleration. .............................. 204Â Table 111. Characteristics of the base test bed â right-turn deceleration. ................................................ 206Â Table 112. Characteristics of the right-turn lane test bed â right-turn deceleration. ................................. 208Â Table 113. Performance relationships planned for development â TWLTL vs. non-traversable median. 210Â Table 114. Data elements possibly affecting performance â TWLTL vs. non-traversable median. ......... 211Â Table 115. Characteristics of the TWLTL test bed â TWLTL vs. non-traversable median. .................... 214Â Table 116. Characteristics of the NTM test bed â TWLTL vs. non-traversable median. ......................... 215Â Table 117. Field data collected at each calibration site â VISSIM calibration. ........................................ 220Â Table 118. Supplemental conflict data collected in the field at each calibration site. .............................. 225Â Table 119. Study site locations â driveway design. .................................................................................. 228Â Table 120. Study site characteristics â driveway design. .......................................................................... 229Â Table 121. Databases â driveway design. ................................................................................................. 229Â Table 122. Site characteristics data â driveway design. ............................................................................ 230Â Table 123. Traffic characteristics data â driveway design. ....................................................................... 231Â Table 124. Operations performance measure data â driveway design. ..................................................... 232Â Table 125. Pedestrian and bicycle conflict data â driveway design.......................................................... 233Â Table 126. Crash database â driveway design. ......................................................................................... 234Â Table 127. Site volume levels â driveway design. .................................................................................... 238Â Table 128. Data fields in output database for operations study â right-turn deceleration. ....................... 239Â Table 129. Summary statistics for average bicycle delay â right-turn deceleration. ................................ 242Â Table 130. Summary statistics for average bus delay â right-turn deceleration. ...................................... 243Â Table 131. Summary statistics for average truck delay â right-turn deceleration. .................................... 243Â Table 132. Data fields in output database for safety study â right-turn deceleration................................ 245Â Table 133. Summary statistics for bus conflict frequency â right-turn deceleration. ............................... 248Â Table 134. Summary statistics for truck conflict frequency â right-turn deceleration.............................. 249Â Table 135. Data fields in output database for operations study â TWLTL vs. non-traversable median. .. 251Â
xii Table 136. Summary statistics for bicycle and truck speed â TWLTL vs. non-traversable median. ....... 254Â Table 137. Study site description â TWLTL vs. non-traversable median. ............................................... 255Â Table 138. Databases â TWLTL vs. non-traversable median. .................................................................. 256Â Table 139. Site characteristics data â TWLTL vs. non-traversable median. ............................................ 256Â Table 140. Crash database â TWLTL vs. non-traversable median. .......................................................... 257Â Table 141. Adjacent land use characteristics â TWLTL vs. non-traversable median............................... 259Â Table 142. Site characteristics summary â TWLTL vs. non-traversable median. .................................... 260Â Table 143. Crash characteristics summary â TWLTL vs. non-traversable median. ................................. 261Â Table 144. Segment site characteristics â VISSIM calibration. ................................................................ 262Â Table 145. Intersection site characteristics â VISSIM calibration. ........................................................... 264Â Table 146. Data fields in database for calibration study â VISSIM calibration. ...................................... 265Â Table 147. Summary of observed operations performance measures â VISSIM calibration. .................. 269Â Table 148. Data fields in output database for calibration study â VISSIM calibration. ........................... 270Â Table 149. Simulation parameters for sensitivity analysis â VISSIM calibration. ................................... 273Â Table 150. ANOVA Test for simulation parameters â VISSIM calibration. ............................................ 273Â Table 151. Summary of simulated operations performance measures â VISSIM calibration. ................. 275Â Table 152. Comparison of observed and simulated operational measures â VISSIM calibration. ........... 276Â Table 153. Recommended values for simulation parameters â VISSIM calibration. ............................... 277Â Table 154. Data fields in database for calibration study â SSAM calibration. ......................................... 278Â Table 155. Summary of observed traffic conflicts â SSAM calibration. .................................................. 279Â Table 156. Summary of simulated traffic conflicts â SSAM calibration. ................................................. 281Â Table 157. Comparison of observed and simulated safety measures â SSAM calibration. ...................... 282Â Table 158. Recommended values for simulation parameters â SSAM calibration. ................................. 282Â Table 159. Factors affecting a change in operational performance â right-turn deceleration. .................. 285Â Table 160. Statistics for variables in the bicycle operations model â right-turn deceleration. ................. 286Â Table 161. Predictive model calibration statistics, bicycle operations model â right-turn deceleration. .. 287Â Table 162. Statistics for variables in the transit operations model â right-turn deceleration. ................... 288Â Table 163. Predictive model calibration statistics, transit operations model â right-turn deceleration. ... 289Â Table 164. Statistics for variables in the truck operations model â right-turn deceleration. ..................... 292Â Table 165. Predictive model calibration statistics, truck operations model â right-turn deceleration. ..... 292Â Table 166. Simulated conflicts and observed crashes for hourly examination â right-turn deceleration. 296Â Table 167. Simulated conflicts and observed crashes for daily examination â right-turn deceleration. ... 297Â Table 168. Factors affecting a change in safety performance â right-turn deceleration. .......................... 299Â Table 169. Statistics for variables in the transit vehicle safety model â right-turn deceleration. ............. 300Â Table 170. Predictive model calibration statistics, transit vehicle safety model â right-turn deceleration. .................................................................................................................................................................. 301Â Table 171. Statistics for variables in the truck-related safety model â right-turn deceleration. ............... 305Â Table 172. Predictive model calibration statistics, truck safety model â right-turn deceleration. ............ 305Â Table 173. Factors affecting a change in operational performance â TWLTL vs. non-traversable median. .................................................................................................................................................................. 310Â Table 174. Statistics for variables in the bicycle operations model, TWLTL â TWLTL vs. non-traversable median. ...................................................................................................................................................... 311Â Table 175. Predictive model calibration statistics, bicycle operations model, TWLTL â TWLTL vs. non- traversable median. ................................................................................................................................... 312Â Table 176. Statistics for variables in the bicycle operations model, non-traversable median â TWLTL vs. non-traversable median. ............................................................................................................................ 313Â Table 177. Predictive model calibration statistics, bicycle operations model, non-traversable median â TWLTL vs. non-traversable median. ........................................................................................................ 314Â
xiii Table 178. Statistics for variables in the truck operations model, TWLTL â TWLTL vs. non-traversable median. ...................................................................................................................................................... 316Â Table 179. Predictive model calibration statistics, truck operations model, TWLTL â TWLTL vs. non- traversable median. ................................................................................................................................... 316Â Table 180. Statistics for variables in the truck operations model, non-traversable median â TWLTL vs. non-traversable median. ............................................................................................................................ 319Â Table 181. Predictive model calibration statistics, truck operations model, non-traversable median â TWLTL vs. non-traversable median. ........................................................................................................ 319Â Table 182. Predictive model calibration statistics, transit-related crashes â TWLTL vs. non-traversable median. ...................................................................................................................................................... 333Â Table 183. Predictive model calibration statistics, transit-related crashes, TM segments â TWLTL vs. non-traversable median. ............................................................................................................................ 334Â Table 184. Predictive model calibration statistics, transit-related crashes, NTM segments â TWLTL vs. non-traversable median. ............................................................................................................................ 336Â Table 185. Predictive model calibration statistics, truck-related crashes â TWLTL vs. non-traversable median. ...................................................................................................................................................... 344Â Table 186. Predictive model calibration statistics, truck-related crashes, TM segments â TWLTL vs. non- traversable median. ................................................................................................................................... 345Â Table 187. Predictive model calibration statistics, truck-related crashes, NTM segments. ...................... 347Â Table 188. Crash severity distribution, transit-related crashes â TWLTL vs. non-traversable median. ... 356Â Table 189. Crash type distribution, transit-related crashes â TWLTL vs. non-traversable median. ........ 356Â Table 190. Comparison of transit-related average crash frequency for alternative median types â TWLTL vs. non-traversable median. ...................................................................................................................... 358Â Table 191. Comparison of alternative lane and shoulder width combinations, transit-vehicle safety â TWLTL vs. non-traversable median. ........................................................................................................ 360Â Table 192. Crash severity distribution, truck-related crashes â TWLTL vs. non-traversable median. ..... 364Â Table 193. Crash type distribution, truck-related crashes â TWLTL vs. non-traversable median. .......... 364Â Table 194. Comparison of truck-related average crash frequency for alternative median types â TWLTL vs. non-traversable median. ...................................................................................................................... 366Â Table 195. Comparison of alternative lane and shoulder width combinations, truck-vehicle safety â TWLTL vs. non-traversable median. ........................................................................................................ 367Â
xiv Preface Access management projects and transportation projects including access management techniques are affected by funding and the policies used by state and local authorities to initiate police powers in addressing new and existing access connections. In many cases, overall cost, cost effectiveness, and enforcement policies play increasingly larger roles in scoping projects that may also be affected by physical constraints or social and/or environmental considerations. For these reasons, it may not always be feasible to achieve the operational and/or safety outcomes documented herein when an access management technique is proposed for a given location. Transportation professionals should consider the potential use of transportation facilities by motorists, pedestrians, bicyclists, public transit, and truck modes. For any given access management technique, the professionals should try to understand the potential operational and safety performance tradeoffs associated with each travel mode, how they may be impacted, and potential countermeasures to balance project objectives. The predictive performance relationships documented herein are intended to provide information about these tradeoffs. The safety and operational performance relationships documented in this report generally reflect a suburban/urban land use context. Performance relationships may differ under a central business district context. The information obtained from the use of these relationships is not intended to supersede engineering judgment by the knowledgeable design professional. The fact that new operational and safety performance relationships are presented herein does not imply that existing roadways or highways are unsafe, nor does it mandate the initiation of improvement projects.
xv Abstract This report documents and presents the results of the study of the safety and operational effects of selected access management (AM) techniques. The focus of the study was on each techniqueâs effect on the pedestrian, bicycle, transit, and truck travel modes. The literature was reviewed to identify existing information describing the quantitative effect of a technique on modal safety or operations. Practitioners were surveyed to identify those techniques for which information was most needed. A prioritized list of techniques was established. Field and simulation data were collected to support the development of models for predicting the safety or operational effect of a treatment on each travel mode. These models, along with models found in the literature, were incorporated into the Guide for the Analysis of Multimodal Corridor Access Management (Guide). The Guide was written for practitioners to use when evaluating alternative AM techniques. It consolidates 74 access management techniques into 19 groups of related AM techniques (e.g., non-traversable medians, frontage and service roads). It is unique in its parallel treatment of five travel modes and can be effectively used to inform the selection of alternative AM techniques based on consideration of the safety and operation of all affected travel modes. The Guide represents a first-of-its-kind resource document to support multimodal evaluation and complete-streets design.
xvi Summary The roadway system must accommodate many types of usersâbicycles, passenger cars, pedestrians, transit, and trucks. User access connections to the roadway are a part of the system. The location and design of these access connections can have a unique effect on the safety or operation of each road user. As the emphasis on considering all users grows, there is a need to better understand these effects and the tradeoff decisions that must be made by practitioners when improving the roadway system. To obtain this better understanding, quantitative relationships must be developed that describe the effect of specific access management (AM) techniques on specific roadway system users. The objective of this research was to identify and determine unknown relationship definitions between AM techniques and the various users/modes along multimodal corridors. The end product is the Guide for the Analysis of Multimodal Corridor Access Management (Guide). The Guide is intended to be used by practitioners for technical analysis and to support their efforts to explain technical findings to non- transportation professionals and public stakeholders. One piece of information that is often needed by practitioners when considering the implementation of an AM technique is the techniqueâs âperformance relationship.â This relationship is defined herein as an analytic model of the effect of an AM technique on the safety or operational performance of a specific travel mode. Literature Review Through a review of the literature, the researchers identified more than 70 AM techniques being used throughout the U.S. The literature review revealed that performance relationships existed in the literature for many of these techniques. However, these relationships almost always focused on the effect of the technique on passenger car (i.e., auto) performance. There were very few relationships in the literature that quantify the effect of a technique on the pedestrian, bicycle, transit, or truck travel modes. Survey Findings The researchers surveyed practitioners and researchers from various agencies and institutions in the U.S. to identify the AM techniques typically used by agencies. The survey was also used to gather respondentsâ opinions on the effects of various AM techniques on the safety or operation of the four non- auto travel modes. A total of 381 individuals responded to the survey, with the majority identifying as consultants (27.3%), state transportation agency staff (27.0%), and university transportation researchers (21.5%). The top AM techniques identified as needing additional analysis with regard to their interaction with the safety and/or operational performance of non-auto modes across all respondents are identified in the following list: ï· Manage spacing of traffic signals (25%); ï· Install non-traversable medians (24%); ï· Manage the location and spacing of unsignalized access (24%); and ï· Install roundabout (24%).
xvii Information Needs Assessment Process Based on the literature review and survey findings, it was determined that there were more AM techniques in use than could be adequately addressed in the research project. As a result, these findings were used to identify those techniques for which information was most needed and that could be developed with the resources available to the project. The technique assessment process occurred in three stages. The level of evaluation detail increased with each stage, and the number of candidate techniques was incrementally reduced at the end of stages 1 and 2. The rationale for this staged approach was to minimize the time required to evaluate a large number of performance relationships, while maximizing the likelihood that the most-needed relationships were developed by this project, within the constraints of project resources. The three stages are outlined in the following list. ï· Stage 1 â Initial selection of techniques. The objective of this stage was to develop and apply a selection procedure that justified reducing the number of candidate techniques from 74 to 20. ï· Stage 2 â Final selection of techniques. The objective of this stage was to develop and apply a refined selection procedure that justified reducing the number of candidate techniques from 20 to six. ï· Stage 3 â Detailed assessment of selected techniques. The objectives of this stage were: (1) to develop a prioritized list of techniques for which performance relationships could be developed in Phase 2 and (2) to identify a proposed research approach for quantifying these relationships. Selection Process The selection process included an evaluation of the utility and development cost of new performance relationships for each candidate technique. In this regard, utility describes the value a performance relationship indirectly provides to the traveling public by more reliably informing decision-makers during the project development process. The selection process incorporated an optimization algorithm with the objective to maximize the total expected utility. The key constraint was that the total cost of developing all selected techniques could not exceed the specified total cost. The researchers refined the list of techniques identified in this manner by using their judgment and experience. Selection Results The six techniques for which information was needed by practitioners and that could have been potentially accommodated within the project resources are identified in Table 1. The estimated cost to develop performance relationships for these techniques was approximately $336,125. This cost slightly exceeded the $325,000 budget for Phase 2, but was considered sufficiently close for the planning phase of the project.
xviii Table 1. Researcherâs prioritized list of techniques to study in Phase 2. Technique (listed by ID code1) Selected Techniques Rank Expected Utility Cost of Study Ratio3 Total: 76.3 $336,125 B-6-10 Install roundabout2 1 13.7 $45,625 0.30 B-3-1 Install median barrier with no direct left-turn ingress or egress. 2 14.0 $48,125 0.29 1c. Establish corner clearance criteria 3 13.7 $48,750 0.28 6b. Locate/relocate the intersection of a parallel frontage road and a crossroad farther from the arterialâcrossroad intersection 4 13.7 $55,625 0.25 4a. Install right-turn deceleration lane or right-turn lane 5 9.3 $45,500 0.21 1a. Establish traffic signal spacing criteria 6 12.0 $92,500 0.13 Notes: 1 â Technique ID codes are referenced to NCHRP Report 420 (Gluck et al., 1999). 2 â Technique added or modified by the NCHRP 03-120 research team. 3 â Ratio = expected utility / cost of study à 1000. The utility score and the estimated development cost were used to determine the priority rank for each technique. The utility-to-cost ratio was used to define the cost effectiveness of developing relationships for a given technique. The technique with the largest ratio was determined to be the most cost-effective technique, so it was given a rank of 1. The technique with the next highest net benefit was given a rank of 2, and so on for the remaining techniques. The prioritized list of techniques from Stage 3 was then presented to the panel. Based on panel input, the list was subsequently revised to include some additional projects. A follow-up meeting was convened with the panel to discuss the recommended six techniques listed in Table 1 and the new techniques. Based on guidance from the panel, revisions were made to the study design for three of the new techniques. The computed utility and development cost for each of the nine techniques is listed in Table 2. The estimated total development cost for the nine techniques is $654,275. Further discussion occurred at the panel meeting to identify those techniques for which (1) performance information is most needed by practitioners and (2) the total development cost was nearly equal to the Phase 2 budget of $325,000. After this discussion, the priorities that were established are indicated in Table 2 by the order in which the techniques are listed. The technique in the first row of the table was given highest priority. The first four techniques listed in the table were the subject of further study in Phase 2.
xix Table 2. Final prioritized list of techniques considered for study in Phase 2. Short Title Supplemental Technique Original Technique (listed by ID code1) E xp ec te d U til ity C os t o f S tu dy A cc um ul at ed C os t Total: 101.5 $654,275 1. Driveway design Install appropriate driveway width and radius Install driveways with the appropriate return radii, throat width, and throat length for the type of traffic to be served2 3.5 $75,000 $75,000 2. Right-turn deceleration -- 4a. Install right-turn deceleration lane or right-turn lane 9.3 45,500 $120,500 3. TWLTL vs. non- traversable median TWLTL vs. non-traversable median 2a.& 2b. Install non-traversable median on undivided highway and replace TWLTL with non-traversable median 14.0 $93,150 $213,650 3c. Install continuous two-way left-turn lane on undivided highway 4. Corner clearance Limit access in the functional intersection area (Part 1) 1c. Establish corner clearance criteria 13.7 $97,500 $311,150 5. Signal spacing -- 1a. Establish traffic signal spacing criteria 12.0 $92,500 $403,650 6. Median barrier w/no lefts -- B-3-1 Install median barrier with no direct left-turn ingress or egress 14.0 $48,125 $451,775 7. Replace parking Replace curb parking with off- street parking B-6-8 Rep lace parallel on-street parking with off-street parking 7.7 $101,250 $553,025 8, Relocate access Limit access in the functional intersection area (Part 2) 6b. Locate/relocate the intersection of a parallel frontage road and a crossroad farther from the arterialâcrossroad intersection 13.7 $55,625 $608,650 9. Roundabout -- B-6-10 Install roundabout2 13.7 $45,625 $654,275 Notes: 1 â Technique ID codes are referenced to NCHRP Report 420 (Gluck et al., 1999). 2 â Technique added or modified by the NCHRP 03-120 research team. Guide for the Analysis of Multimodal Corridor Access Management The initial literature review of 46 documents, mostly national in scope, found very few documented relationships between the 74 identified access management techniques and the four non-auto modes (pedestrian, bicycle, public transit, and truck). Of the 46 documents, only six quantified at least one operational relationship between an access management technique and a non-auto mode, and only six quantified at least one safety relationship. Similarly, only eight documents identified at least one qualitative operational relationship and only ten documents identified at least one qualitative safety relationship. A total of 51 access management techniques (69%) lacked quantitative or qualitative operational relationships for all four non-auto modes, while a total of 64 access management techniques (86%) lacked quantitative or qualitative safety relationships for all four non-auto modes. This result indicated that practitioners would find very little information on the effects of access management techniques on non-auto modes in the references to which they would most likely turn. Therefore, this result also provided strong support for the need to develop a multimodal corridor access management analysis guide to provide this information.
xx Performance Relationships A study design was developed for each of the four techniques identified in Table 2. Elements of this design included the analysis scale (i.e., site or corridor), proposed data source (i.e., simulation, field, crash report), and study method (i.e., beforeâafter or cross-sectional). Simulation was the proposed data source for the operations relationships. In contrast, the combination of crash report and simulation was the proposed data source for the collective set of safety relationships. The study designs for the selected techniques also included details about study site locations and characteristics, simulation test bed characteristics, sample size, and data collection methods. Of the top four techniques listed in Table 2, the study associated with the corner clearance technique was held in abeyance contingent on the successful undertaking of studies associated with the other three techniques. This strategy was used to maximize the probability of success for the three higher priority studies. Challenges associated with these three studies were encountered, which required additional project resources to overcome. As a result, the corner clearance study was not undertaken in this project. Data were collected for the study associated with the driveway design technique. However, a review of the data indicated that the number of pedestrians and bicycles was too low to meet the minimum sample size needed to produce statistically valid results. An assessment of alternative study designs to overcome this deficiency did not reveal the availability of a viable option given the remaining available resources. As a result, the study of the driveway design technique was abandoned. This project successfully developed performance relationships for the right-turn deceleration technique and for the two-way left-turn lane (TWLTL) vs non-traversable median technique. For the right-turn deceleration technique, performance relationships were developed for the following travel modes and performance measure combinations: ï· Model to predict bicycle delay ï· Model to predict transit vehicle delay ï· Model to predict truck delay ï· Model to predict transit vehicle conflict frequency ï· Model to predict truck conflict frequency For the TWLTL vs non-traversable median technique, performance relationships were developed for the following median-type, travel mode, and performance measure combinations: ï· For streets with a TWLTL: o Model to predict bicycle speed o Model to predict truck speed o Model to predict transit crash frequency o Model to predict truck crash frequency ï· For streets with a non-traversable median: o Model to predict bicycle speed o Model to predict truck speed o Model to predict transit crash frequency o Model to predict truck crash frequency Guide for the Analysis of Multimodal Corridor Access Management The gaps in knowledge about the operational and safety relationships between access management techniques and non-auto modes were filledâto the extent possibleâfrom (1) the updated performance relationships for a small number of techniques developed through this projectâs original research, and (2) a supplemental literature review of research reports and journal articles. This supplemental review
xxi identified 16 additional documents containing information on quantitative and/or qualitative relationships between access management techniques and non-auto modes in the areas of operations, safety, or both. As a result of these efforts, the number of access management techniques with no documented operational relationship for any non-auto mode was reduced from 51 to 35, while the number of techniques with no documented safety relationship for any non-auto mode was reduced from 64 to 36. Thus, although there are still many relationships where further research is required, considerable progress was made in consolidating and updating the available knowledge. The Guide for the Analysis of Multimodal Corridor Access Management (Guide) produced by this project documents the known operational and safety relationships between access management techniques and the automobile, pedestrian, bicycle, public transit, and truck modes. The Guide consolidates the 74 access management techniques into 19 groups of related techniques (e.g., non-traversable medians, frontage and service roads). Then, for each group, the Guide presents the following information: ï· Table summarizing general operations and safety performance trends (i.e., better performance, worse performance, mixed performance, unchanged performance, no documented relationship) by technique and travel mode; ï· Table summarizing the availability of documented operations and safety relationships (i.e., quantitative relationship, qualitative relationship, no documented relationship) by technique and mode; ï· Table summarizing in words the known operations and safety relationships by mode; ï· Descriptions of available methods for quantifying the operations and safety of access management techniques on individual modes; and ï· References to related technique groups within the Guide and to external documents (in particular, the Access Management Manual, 2nd Edition, and the Access Management Application Guidelines) providing more information about particular techniques. The Guide is unique in its parallel treatment of five travel modes. It consolidates the body of knowledge on the safety and operational effects of each technique on each travel mode. It can be effectively used to inform the selection of alternative AM techniques based on consideration of the safety and operation of all affected travel modes. The Guide represents a first-of-its-kind resource document to support multimodal evaluation and complete-streets design.