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NCHRP Web-Only Document 318 Safety Prediction Models for Six-Lane and One-Way Urban and Suburban Arterials Dominique Lord Srinivas Geedipally Michael P. Pratt Eun Sug Park S. Hadi Khazraee Kay Fitzpatrick Texas A&M Transportation Institute The Texas A&M University System College Station, TX Conduct of Research Report for NCHRP Project 17-58 Submitted June 2016 NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Systematic, well-designed, and implementable research is the most effective way to solve many problems facing state departments of transportation (DOTs) administrators and engineers. Often, highway problems are of local or regional interest and can best be studied by state DOTs individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation results in increasingly complex problems of wide interest to highway authorities. These problems are best studied through a coordinated program of cooperative research. Recognizing this need, the leadership of the American Association of State Highway and Transportation Officials (AASHTO) in 1962 initiated an objective national highway research program using modern scientific techniquesâthe National Cooperative Highway Research Program (NCHRP). NCHRP is supported on a continuing basis by funds from participating member states of AASHTO and receives the full cooperation and support of the Federal Highway Administration (FHWA), United States Department of Transportation, under Agreement No. 693JJ31950003. 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, FTA, GHSA, NHTSA, 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; the FHWA; 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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C O O P E R A T I V E R E S E A R C H P R O G R A M S CRP STAFF FOR NCHRP WEB-ONLY DOCUMENT 318 Christopher J. Hedges, Director, Cooperative Research Programs Lori L. Sundstrom, Deputy Director, Cooperative Research Programs Waseem Dekelbab, Associate Program Manager, National Cooperative Highway Research Program David Jared, Senior Program Officer Traci Caldwell, Senior Program Assistant Natalie Barnes, Director of Publications Heather DiAngelis, Associate Director of Publications Jennifer Correro, Assistant Editor NCHRP PROJECT 17-58 PANEL Field of TrafficâArea of Safety Hadi Shirazi, Louisiana Department of Transportation and Development, Baton Rouge, LA (Chair) Geni Bahar, NAVIGATS Inc., Toronto, ON W. Martin Bretherton, Jr., HNTB Corporation, Atlanta, GA Hampton Gabler, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA Tim Harmon, Holly Springs, NC Howard Lubliner, Burns & McDonnell Engineering Company, Lawrence, KS Grant Schultz, Brigham Young University, Provo, UT Lance Simmons, Texas Department of Transportation, Atlanta, TX Shyuan-Ren (Clayton) Chen, FHWA Liaison Kelly Hardy, AASHTO Liaison Bernardo B. Kleiner, TRB Liaison ACKNOWLEDGMENTS The research report herein was performed under NCHRP Project 17-58 by the Texas A&M Transportation Institute (TTI). Dr. Domonique Lord of Texas A&M University served as the principle investigator (PI), and Dr. Kay Fitzpatrick of TTI served as the co-PI of the project and supervised the research conducted by TTI. The research supervisors were assisted by the following individuals: Dr. Srinivas Geedipally, Mr. Mike Pratt, Dr. Eun Sug Park, and Mr. S. Hadi Khazraee. The research team would like to thank everybody from the federal, state, and local transportation agencies, fellow researchers, and colleagues who helped us over the entire span of this research. The team would also like to recognize all the student workers and support staff who worked very hard to fulfill the requirements of this project. The feedback received from the workshop participants near the end of the project was appreciated. The participants provided very useful comments and suggestions. Finally, the team thanks TTI Communications for their input and review of the final report.
iv CONTENTS LIST OF FIGURES ................................................................................................................... viii LIST OF TABLES ....................................................................................................................... ix SUMMARY ................................................................................................................................... 1 INTRODUCTION .................................................................................................................... 1 WORK PLAN ........................................................................................................................... 1 FINDINGS ................................................................................................................................ 2 RECOMMENDATIONS .......................................................................................................... 3 CHAPTER 1. INTRODUCTION ................................................................................................ 4 RESEARCH OBJECTIVES AND STRATEGIES .................................................................. 4 RESEARCH SCOPE ................................................................................................................ 5 RESEARCH APPROACH ....................................................................................................... 5 ORGANIZATION OF THE REPORT ..................................................................................... 6 CHAPTER 2. LITERATURE REVIEW.................................................................................... 7 OVERVIEW OF HSM CHAPTER 12 ..................................................................................... 7 Safety Prediction Methodology .......................................................................................... 7 Incorporating Crash History into Prediction .................................................................. 9 Crash Severity and Collision Type ................................................................................ 9 Data for Model Development ............................................................................................. 9 CMFs................................................................................................................................. 10 SAFETY PREDICTION FOR ARTERIALS WITH SIX OR MORE LANES ..................... 11 Safety Prediction at Roadway Segments .......................................................................... 11 Description of Models in the Literature ....................................................................... 13 Comparison of Models ................................................................................................. 22 Comparison of CMFs ................................................................................................... 26 Safety Prediction at Intersections ...................................................................................... 32 Signalized Intersections ............................................................................................... 34 Unsignalized Intersections ........................................................................................... 39 SAFETY PREDICTION FOR ONE-WAY ARTERIALS ..................................................... 44 Safety Prediction at Roadway Segments .......................................................................... 44 Safety Prediction at Intersections ...................................................................................... 45 CHAPTER 3. FRAMEWORK FOR SAFETY PREDICTION ............................................. 49 MODEL CALIBRATION METHODS .................................................................................. 49 Safety Prediction Method ................................................................................................. 49 Base Models + CMFs ....................................................................................................... 50 Full Model ......................................................................................................................... 51 CRASH SEVERITY DISTRIBUTION .................................................................................. 52 CRASH TYPE DISTRIBUTION ........................................................................................... 52 DISPERSION PARAMETER ................................................................................................ 53 INTERACTION AMONG FACTOR EFFECTS ................................................................... 54 PROPOSED METHODOLOGY ............................................................................................ 54
v Segments ........................................................................................................................... 54 Intersections ...................................................................................................................... 55 Standard Error of CMFs .................................................................................................... 56 CHAPTER 4. DEVELOPMENT OF PROJECT DATABASE .............................................. 58 DATA SOURCES .................................................................................................................. 58 SELECTION OF ROADWAY SEGMENT TYPES .............................................................. 59 SELECTION OF INTERSECTION TYPES .......................................................................... 60 DATA COLLECTION ........................................................................................................... 61 Site Characteristics Data for Roadway Segments ............................................................. 61 Site Characteristics Data for Intersections ........................................................................ 68 CRASH DATA ....................................................................................................................... 78 SUPPLEMENTAL DATA COLLECTIONâPEDESTRIAN DATA ................................... 85 CHAPTER 5. PREDICTIVE MODELS FOR URBAN AND SUBURBAN ROADWAY SEGMENTS WITH SIX OR MORE LANES ......................................................................... 88 BACKGROUND .................................................................................................................... 88 CALIBRATION DATA ......................................................................................................... 90 MODEL DEVELOPMENTâSIX-OR-MORE-LANE ARTERIALS ................................... 92 VEHICLE-PEDESTRIAN COLLISIONS ............................................................................. 99 VEHICLE-BICYCLE COLLISIONS ................................................................................... 100 CMFS FOR SIX-OR-MORE-LANE ARTERIALS ............................................................. 101 Lane Width CMF ............................................................................................................ 102 Outside Shoulder Width CMF ........................................................................................ 103 Median Width CMF ........................................................................................................ 103 Median Barrier CMF ....................................................................................................... 104 Railroad Crossing Presence CMF ................................................................................... 106 Driveway CMF ............................................................................................................... 107 Roadside Fixed-Object CMF .......................................................................................... 108 CHAPTER 6. PREDICTIVE MODELS FOR INTERSECTIONS OF URBAN AND SUBURBAN ARTERIALS WITH SIX OR MORE LANES ............................................... 110 CALIBRATION DATA ....................................................................................................... 110 MODEL DEVELOPMENTâTWO-WAY STREET INTERSECTIONS .......................... 111 VEHICLE-PEDESTRIAN COLLISIONS ........................................................................... 118 VEHICLE-BICYCLE COLLISIONS ................................................................................... 120 CMFS FOR 2Ã2 INTERSECTIONS .................................................................................... 121 Lighting CMF ................................................................................................................. 121 Intersection Left-Turn Signal Phasing CMF ................................................................... 122 RTOR CMF .................................................................................................................... 122 U-turn Prohibition CMF ................................................................................................. 122 Right-Turn Channelization CMF .................................................................................... 123 Number of Lanes CMF ................................................................................................... 123 CHAPTER 7. PREDICTIVE MODELS FOR URBAN AND SUBURBAN ONE-WAY ARTERIAL ROADWAY SEGMENTS .................................................................................. 125 CALIBRATION DATA ....................................................................................................... 125
vi MODEL DEVELOPMENTâONE-WAY ARTERIALS .................................................... 126 VEHICLE-PEDESTRIAN COLLISIONS ........................................................................... 133 VEHICLE-BICYCLE COLLISIONS ................................................................................... 134 CMFS FOR ONE-WAY ARTERIALS ................................................................................ 134 Right Shoulder Width CMF ............................................................................................ 134 On-Street Parking CMF .................................................................................................. 135 Driveway CMF ............................................................................................................... 136 CHAPTER 8. PREDICTIVE MODELS FOR INTERSECTIONS OF URBAN AND SUBURBAN ONE-WAY ARTERIALS ................................................................................. 138 CALIBRATION DATA ....................................................................................................... 138 MODEL DEVELOPMENTâONE-WAY STREET INTERSECTIONS ........................... 138 Vehicle-Pedestrian Collisions ......................................................................................... 144 Vehicle-Bicycle Collisions ............................................................................................. 146 CMFS FOR 1Ã2 OR 1Ã1 INTERSECTIONS ...................................................................... 146 Lighting CMF ................................................................................................................. 147 Number of Lanes CMF ................................................................................................... 147 CHAPTER 9. SEVERITY DISTRIBUTION FUNCTIONS ................................................ 149 METHODOLOGY ............................................................................................................... 149 SIX-OR-MORE-LANE ARTERIAL SEGMENTS ............................................................. 151 Predicted Probabilities .................................................................................................... 153 Area Type ................................................................................................................... 153 Speed Limit ................................................................................................................ 153 Road Type .................................................................................................................. 154 ONE-WAY ARTERIAL SEGMENTS ................................................................................. 154 Predicted Probabilities .................................................................................................... 155 Lane Width ................................................................................................................. 155 Right Shoulder Width ................................................................................................ 156 Area Type ................................................................................................................... 156 Bike Lanes .................................................................................................................. 157 TWO-WAY STREET SIGNALIZED INTERSECTIONS .................................................. 157 Predicted Probabilities .................................................................................................... 159 Area Type ................................................................................................................... 159 Right Turn on Red ...................................................................................................... 159 U-turn ......................................................................................................................... 160 Left-Turn Lanes ......................................................................................................... 160 Lighting ...................................................................................................................... 160 ONE-WAY STREET SIGNALIZED INTERSECTIONS ................................................... 161 Predicted Probabilities .................................................................................................... 162 Area Type ................................................................................................................... 162 Left-Turn Lane ........................................................................................................... 163 Channelization ........................................................................................................... 163 STOP-CONTROLLED INTERSECTIONS ......................................................................... 164 Predicted Probabilities .................................................................................................... 165 Area Type ................................................................................................................... 165 Lighting ...................................................................................................................... 165
vii Left-Turn Lanes ......................................................................................................... 166 CHAPTER 10. SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS ............... 167 REFERENCES .......................................................................................................................... 169 APPENDIX A. PROPOSED REVISION TO HSM CHAPTER 12âPREDICTIVE METHOD FOR URBAN AND SUBURBN ARTERIALS .....................................................174 APPENDIX B. WORKSHOP SAMPLE PROBLEMS ..........................................................387 APPENDIX C. SPREADSHEET PROGRAM AND USER MANUAL The Safety Prediction Models for Six-Lane and One-Way Urban and Suburban Arterials Spreadsheet xlsm file is available at https://www.dropbox.com/s/skkq4pjxet3dkia/NCHRP%20W318_Appendix%20C_User%20Man ual.doc?dl=0 and the User Manual is available at https://www.dropbox.com/s/hgtjf6aamc9wmlp/NCHRP%20W318_Appendix%20C_Safety%20P rediction%20Models%20for%20Six-Lane%20and%20One- Way%20Urban%20and%20Suburban%20Arterials%20Spreadsheet.xlsm?dl=0
viii LIST OF FIGURES Figure 1. Models for six-lane undivided urban or suburban arterials. .......................................... 24 Figure 2. Models for six-lane urban or suburban arterials with nonrestrictive medians. ............. 25 Figure 3. Models for six-lane urban or suburban arterials with restrictive medians. ................... 25 Figure 4. Models for six-lane divided urban or suburban arterials. .............................................. 26 Figure 5. Lane width CMFs. ......................................................................................................... 28 Figure 6. Outside shoulder width CMFs. ...................................................................................... 29 Figure 7. Inside shoulder width CMFs. ........................................................................................ 29 Figure 8. Median width CMFs. ..................................................................................................... 30 Figure 9. Horizontal curvature CMFs. .......................................................................................... 31 Figure 10. Models for urban four-leg signalized intersections. .................................................... 36 Figure 11. Models for urban four-leg stop-controlled intersections. ............................................ 41 Figure 12. Models for urban three-leg stop-controlled intersections. ........................................... 41 Figure 13. Models for four-leg diamond interchange ramp terminals (Bonneson et al., 2012). .. 48 Figure 14. Definition of roadway segments and intersections (AASHTO, 2010). ....................... 89 Figure 15. Graphical form of the SPF for FI multiple-vehicle collisions, six-or-more-lane arterials. ................................................................................................. 97 Figure 16. Graphical form of the SPF for FI single-vehicle collisions, six-or-more-lane arterials. ................................................................................................. 97 Figure 17. Graphical form of the SPF for PDO multiple-vehicle collisions, six-or-more-lane arterials. ................................................................................................. 98 Figure 18. Graphical form of the SPF for PDO single-vehicle collisions, six-or-more-lane arterials. ................................................................................................. 98 Figure 19. Lane width CMF, six-or-more-lane arterials. ............................................................ 102 Figure 20. Outside shoulder width CMF, six-or-more-lane arterials. ......................................... 103 Figure 21. Median width CMF, six-or-more-lane arterials. ........................................................ 104 Figure 22. Median barrier CMF for multiple-vehicle crashes, six-or-more-lane arterials. ........ 105 Figure 23. Median barrier CMF for single-vehicle crashes, six-or-more-lane arterials. ............ 106 Figure 24. Railroad crossing CMF, six-or-more-lane arterials. .................................................. 106 Figure 25. Major driveway CMF, six-or-more-lane arterials. .................................................... 107 Figure 26. Minor driveway CMF, six-or-more-lane arterials. .................................................... 108 Figure 27. Graphical form of the intersection SPF for crashes on three-leg stop-controlled intersections (3ST). ................................................................................ 116 Figure 28. Graphical form of the intersection SPF for crashes on three-leg signalized intersections (3SG). ....................................................................................... 116 Figure 29. Graphical form of the intersection SPF for crashes on four-leg stop-controlled intersections (4ST). ................................................................................ 117 Figure 30. Graphical form of the intersection SPF for crashes on four-leg signalized intersections (4SG). ....................................................................................... 117 Figure 31. Graphical form of the SPF for FI multiple-vehicle collisions, one-way arterials. .... 131 Figure 32. Graphical form of the SPF for FI single-vehicle collisions, one-way arterials. ........ 131 Figure 33. Graphical form of the SPF for PDO multiple-vehicle collisions, one-way arterials. 132 Figure 34. Graphical form of the SPF for PDO single-vehicle collisions, one-way arterials. .... 132 Figure 35. Right shoulder width CMF, one-way arterials. ......................................................... 135 Figure 36. Major commercial driveway CMF, one-way arterials. ............................................. 136
ix Figure 37. Minor driveway CMF, one-way arterials. ................................................................. 137 Figure 38. Graphical form of the intersection SPF for crashes on one-way street three-leg stop-controlled intersections (3ST). ................................................................. 142 Figure 39. Graphical form of the intersection SPF for crashes on one-way street three-leg signalized intersections (3SG). ........................................................................ 142 Figure 40. Graphical form of the intersection SPF for crashes on one-way street four-leg stop-controlled intersections (4ST). .................................................................. 143 Figure 41. Graphical form of the intersection SPF for crashes on one-way street four-leg signalized intersections (4SG). ....................................................................................... 143 Figure 42. Comparison of the SPF by intersection category for crashes on one-way street four-leg signalized intersections (4SG). ................................................................ 144 LIST OF TABLES Table 1. Input variables of the safety prediction models for six-lane arterial segments and the HSM Chapter 12 methodology. ................................................................ 12 Table 2. CMF values for land use and parking presence (based on Bonneson and McCoy, 1997). ................................................................................................................. 20 Table 3. CMFc values (based on Hadi et al., 1995). ........................................................................... 21 Table 4. PDO proportions (based on Squires and Parsonson, 1989). ................................................ 22 Table 5. Crash rates and input variables for six-lane roadway segment models in the literature. .... 23 Table 6. Land use CMF values. .......................................................................................................... 27 Table 7. On-street parking CMF values. ............................................................................................ 27 Table 8. Access or crossing point presence CMFs............................................................................. 32 Table 9. CMFs in intersection safety prediction models.................................................................... 33 Table 10. Input variable values for intersection model comparisons. ............................................... 34 Table 11. Signal timing parameters CMFs. ........................................................................................ 36 Table 12. Left-turn lane CMFs for four-leg signalized intersections. ............................................... 37 Table 13. Right-turn lane CMFs for four-leg signalized intersections. ............................................. 38 Table 14. Right-turn channelization CMFs for signalized intersections (based on Bonneson and Pratt, 2009). .................................................................................... 39 Table 15. Left-turn lane CMFs for unsignalized intersections. ......................................................... 42 Table 16. Right-turn lane CMFs for unsignalized intersections. ....................................................... 43 Table 17. Right-turn channelization CMFs for unsignalized intersections (based on Bonneson and Pratt, 2009). .................................................................................... 43 Table 18. Midblock crash rates and counts on one-way and two-way streets (based on Hocherman et al., 1990). ........................................................................................ 45 Table 19. Conflict points at four-leg intersections (based on Smith and Hart, 1949). ...................... 46 Table 20. Intersection CMFs for two-way to one-way frontage road conversion (based on Eisele et al., 2011). ................................................................................................. 46 Table 21. Size of data from different states. ....................................................................................... 58 Table 22. Distribution of roadway segment data by segment type and state. ................................... 60 Table 23. Distribution of intersection data by intersection type and state. ........................................ 61
x Table 24. List of data variables collected for roadway segments. ..................................................... 62 Table 25. Descriptive statistics for two-way roadway segment variables. ........................................ 64 Table 26. Descriptive statistics for one-way roadway segment variables. ........................................ 66 Table 27. List of data variables collected for intersections as a whole. ............................................ 68 Table 28. List of data variables collected for individual streets (major and minor). ........................ 69 Table 29. Descriptive statistics for continuous variables for 2Ã2 intersections. ............................... 70 Table 30. Breakdown of the number of 2Ã2 intersections by categorical variablesâ data variables for intersection as a whole. ............................................................................. 70 Table 31. Breakdown of the number of 2Ã2 intersections by categorical variablesâ major-street data variables. ..................................................................................................... 71 Table 32. Breakdown of the number of 2Ã2 intersections by categorical variablesâ minor-street data variables. ..................................................................................................... 72 Table 33. Descriptive statistics for continuous variables for 1Ã2 intersections. ............................... 73 Table 34. Breakdown of the number of 1Ã2 intersections by categorical variablesâ data variables for intersection as a whole or for one-way street data variables. ................... 74 Table 35. Breakdown of the number of 1Ã2 intersections by categorical variablesâ two-way street data variables. ................................................................................................ 75 Table 36. Descriptive statistics for continuous variables for 1Ã1 intersections. ............................... 76 Table 37. Breakdown of the number of 1Ã1 intersections by categorical variablesâ data variables for intersection as a whole or major-street data variables. ............................. 77 Table 38. Breakdown of the number of 1Ã1 intersections by categorical variablesâ minor-street data variables. ..................................................................................................... 78 Table 39. Summary of crash frequency and exposure data for roadway segments. ......................... 80 Table 40. Summary of crash type data for roadway segments. ......................................................... 81 Table 41. Summary of crash frequency and exposure data for intersectionsâ Texas and Illinois. ................................................................................................................... 82 Table 42. Summary of crash frequency and exposure data for intersectionsâ California and Michigan. ........................................................................................................ 83 Table 43. Summary of crash type data for intersectionâTexas and Illinois. ................................... 84 Table 44. Summary of crash type data for intersectionâCalifornia and Michigan. ........................ 85 Table 45. Sample size based on intersection type and location. ........................................................ 86 Table 46. Descriptive statistics for collected data at signalized intersections in California and San Antonio, Texas. ....................................................................................... 87 Table 47. Variables acquired from state databases for six-or-more-lane arterials. ........................... 91 Table 48. Supplemental data collected for six-or-more-lane arterials. .............................................. 92 Table 49. Calibrated coefficients for FI crashes on six-or-more-lane arterials. ................................ 95 Table 50. Calibrated coefficients for PDO crashes on six-or-more-lane arterials. ........................... 96 Table 51. Distribution of multiple-vehicle collisions for roadway segments by manner of collision type. ........................................................................................................ 99 Table 52. Distribution of single-vehicle crashes for roadway segments by collision type for arterials with six or more lanes. ................................................................................ 99 Table 53. Pedestrian crash adjustment factor for two-way roadway segments. .............................. 100 Table 54. Bicycle crash adjustment factor for two-way roadway segments. .................................. 101 Table 55. Increase in crashes with driveways. ................................................................................. 108 Table 56. Roadside fixed-object CMF, six-or-more-lane arterials. ................................................. 109 Table 57. Supplemental data collected for intersections as a whole. .............................................. 111
xi Table 58. Supplemental data collected for individual streets (major and minor). .......................... 111 Table 59. Calibrated coefficients for FI crashes at two-way street intersections. ........................... 114 Table 60. Calibrated coefficients for PDO crashes at two-way street intersections. ...................... 115 Table 61. Distribution of total vehicle collisions for intersections with six or more lanes by collision type. ......................................................................................................... 118 Table 62. Pedestrian crash adjustment factors: two-way street intersections. ................................ 120 Table 63. Bicycle crash adjustment factors: two-way street intersections. ..................................... 121 Table 64. Nighttime crash proportions for unlighted intersections. ................................................ 122 Table 65. CMF for major-street left-turn signal phasing. ................................................................ 122 Table 66. CMF for number of lanes at a signalized intersection. .................................................... 124 Table 67. Variables acquired from state databases for one-way arterials. ...................................... 125 Table 68. Supplemental data collected for one-way arterials. ......................................................... 126 Table 69. Calibrated coefficients for FI crashes on one-way arterials. ........................................... 129 Table 70. Calibrated coefficients for PDO crashes on one-way arterials. ....................................... 130 Table 71. Distribution of multiple-vehicle collisions for roadway segments by manner of collision type. ...................................................................................................... 133 Table 72. Distribution of single-vehicle crashes for roadway segments by collision type for arterials with six or more lanes. ............................................................... 133 Table 73. Pedestrian crash adjustment factor for one-way roadway segments. .............................. 133 Table 74. Bicycle crash adjustment factor for one-way roadway segments. .................................. 134 Table 75. Values of bpk used in determining the CMF for on-street parking. ................................. 135 Table 76. Roadside fixed-object CMF, one-way arterials. .............................................................. 137 Table 77. Calibrated coefficients for FI crashes at one-way street intersections. ........................... 140 Table 78. Calibrated coefficients for PDO crashes at one-way street intersections. ....................... 141 Table 79. Distribution of total vehicle collisions for 1Ã2 or 1Ã1 intersections by collision type. . 144 Table 80. Pedestrian crash adjustment factors: one-way street intersections. ................................. 146 Table 81. Bicycle crash adjustment factors: one-way street intersections. ..................................... 146 Table 82. Nighttime crash proportions for unlighted intersections. ................................................ 147 Table 83. CMF for number of lanes at a signalized intersection. .................................................... 148 Table 84. Crash SDF: six-or-more-lane arterials. ............................................................................ 152 Table 85. Crash severity distribution of six-or-more-lane segments based on area type. .............. 153 Table 86. Crash severity distribution of six-or-more-lane segments based on posted speed limit. ................................................................................................................ 153 Table 87. Crash severity distribution of six-or-more-lane segments based on road type. .............. 154 Table 88. Crash SDF: one-way roadways. ....................................................................................... 154 Table 89. Crash severity distribution of one-way segments based on lane width. ......................... 156 Table 90. Crash severity distribution of one-way segments based on right shoulder width........... 156 Table 91. Crash severity distribution of one-way segments based on area type. ............................ 157 Table 92. Crash severity distribution of one-way segments based on bike lane presence. ............ 157 Table 93. Crash SDF: two-way street signalized intersections. ....................................................... 158 Table 94. Two-way street signalized intersection severity distribution based on area type. .......... 159 Table 95. Two-way street signalized intersection severity distribution based on RTOR. .............. 159 Table 96. Two-way street signalized intersection severity distribution based on U-turn prohibition. ................................................................................................................ 160 Table 97. Two-way street signalized intersection severity distribution based on major-street left-turn lane. ............................................................................................... 160
xii Table 98. Two-way street signalized intersection severity distribution based on lighting presence. .................................................................................................................. 161 Table 99. Crash SDF: one-way street signalized intersections. ....................................................... 161 Table 100. One-way street signalized intersection severity distribution based on area type. ......... 163 Table 101. One-way street signalized intersection severity distribution based on major-street left-turn lane. .................................................................................................... 163 Table 102. One-way street signalized intersection severity distribution based on channelization. ...................................................................................................................... 164 Table 103. Crash SDF: stop-controlled intersections. ..................................................................... 164 Table 104. Stop-controlled intersection severity distribution based on area type. .......................... 165 Table 105. Stop-controlled intersection severity distribution based on lighting presence. ............ 166 Table 106. Stop-controlled intersection severity distribution based on minor-street left-turn lane. ......................................................................................................................... 166
