SAFETY EVALUATION OF ROUNDABOUTS AT FREEWAY RAMP TERMINALS AND HSM CALIBRATION _______________________________________ A Thesis presented to the Faculty of the Graduate School at the University of Missouri-Columbia _______________________________________________________ In Partial Fulfillment of the Requirements for the Degree Master of Science _____________________________________________________ by JACOB A. BERRY Dr. Carlos Sun, Thesis Supervisor MAY 2017 The undersigned, appointed by the dean of the Graduate School, have examined the thesis entitled SAFETY EVALUATION OF ROUNDABOUTS AT FREEWAY RAMP TERMINALS AND HSM CALIBRATION presented by Jacob Berry, a candidate for the degree of or master of science, and hereby certify that, in their opinion, it is worthy of acceptance. Professor Carlos Sun Professor Praveen Edara Professor Tim Matisziw Dedication I would like to dedicate this to the unwavering support of my family and friends. Thank you to my parents, Jim and Rita, for challenging me to be my best and for the continual love and support that they show in so many ways. To my brother, Alex, for showing a good example. To my girlfriend, Kate, for being patient and strong. I would also like to thank my friends, contemporaries, prior students, and mentors for helping in the completion of all my work, both directly and indirectly. Acknowledgments The author is thankful for the assistance provided by John Miller, Myrna Tucker, Darrel Knierim, and others from the Missouri Department of Transportation. The author also recognizes the contributions of Boris Claros and Xiang Yu who worked in close cooperation throughout the entirety of these projects. The author also would like to acknowledge the help of undergraduate assistants Jeremy Metz, John Perlik, and Eunice Wang. Thanks is also due to a number of mentors for their guidance. ii TABLE OF CONTENTS ACKNOWLEDGMENTS .............................................................................................................. II LIST OF FIGURES........................................................................................................................V LIST OF TABLES.......................................................................................................................VII ABSTRACT .................................................................................................................................. IX EXECUTIVE SUMMARY ............................................................................................................ X CHAPTER 1: INTRODUCTION ....................................................................................................1 1.1. Roundabout Interchange Safety Evaluation ..................................................................1 1.2. Highway Safety Manual Calibration ............................................................................2 CHAPTER 2: LITERATURE REVIEW .........................................................................................3 2.1. Introduction ...................................................................................................................3 2.2. Safety Effects of Roundabout Implementation at an Intersection ................................3 2.3. Roundabout Interchange Terminal Case Studies ..........................................................5 2.4. Proposed Design Considerations to Improve Safety at Roundabouts ..........................7 2.5. Public Opinion of Roundabouts ....................................................................................9 CHAPTER 3: ROUNDABOUT EMPIRICAL BAYES SAFETY EVALUATION METHODOLOGY ............................................................................................................10 3.1. Background .................................................................................................................10 3.2. Project-level Empirical Bayes Methodology ..............................................................12 3.3. Site-specific Empirical Bayes Methodology ..............................................................17 3.4. Crash Prediction Model Calibration to Local Conditions...........................................21 CHAPTER 4: ROUNDABOUT INTERCHANGE SITE SELECTION.......................................24 4.1. Site 1: I-44 and Kingshighway, Rolla, Missouri.........................................................26 4.2. Site 2: I-64 and Spoede Rd, St. Louis, Missouri .........................................................27 4.3. Site 3: US-63 and RT-M, Ashland, Missouri .............................................................29 4.4. Site 4: I-44 and RT-E, Rolla, Missouri .......................................................................31 4.5. Site 5: I-435 and 87th St., Kansas City, Missouri ........................................................33 4.6. Site 6: I-70 and RT-Z, Wentzville, Missouri ..............................................................35 4.7. Site 7: MO-9 and Briarcliff Pkwy., Kansas City, Missouri ........................................37 4.8. Site 8: MO-100 and MO-109, Wildwood, Missouri ...................................................39 CHAPTER 5: DATA COLLECTION FOR ROUNDABOUT SAFETY EVALUATION ..........42 5.1. Geometry, Control Type, and Traffic Volume ...........................................................42 5.2. Crash Data Collection .................................................................................................49 5.3. Crash Reports Review and Assignment ......................................................................52 CHAPTER 6: ROUNDABOUT SAFETY EVALUATION RESULTS .......................................56 6.1. Project-level Safety Evaluation Results ......................................................................56 6.2. Site-specific Safety Evaluation ...................................................................................61 CHAPTER 7: ROUNDABOUT COLLISION DIAGRAMS AND CRASH DISTRIBUTION ...68 iii 7.1. Single-lane Roundabout Terminals.............................................................................68 7.2. Dual-lane Roundabout Terminals ...............................................................................71 CHAPTER 8: HSM CALIBRATION FOR RURAL TWO-LANE UNDIVIDED ROADWAY SEGMENTS ......................................................................................................................76 8.1. Introduction and Scope ...............................................................................................76 8.2. Calibration Data Requirements ...................................................................................76 8.3. HSM Crash Prediction Methodology..........................................................................82 8.4. Sampling Considerations ............................................................................................83 8.5. Data Collection ...........................................................................................................87 8.6. Results and Discussion ...............................................................................................91 CHAPTER 9: HSM CALIBRATION OF URBAN FIVE-LANE ARTERIAL SEGMENTS......96 9.1. Introduction and Scope ...............................................................................................96 9.2. Calibration Data Requirements ...................................................................................96 9.3. HSM Crash Prediction Methodology........................................................................104 9.4. Sampling Considerations ..........................................................................................106 9.5. Data Collection .........................................................................................................110 9.6. Results and Discussion .............................................................................................113 CHAPTER 10: HSM CALIBRATION OF URBAN SIX-LANE FREEWAY SEGMENTS ....119 10.1. Introduction and Scope ...........................................................................................119 10.2. Calibration Data Requirements ...............................................................................119 10.3. HSM Crash Prediction Methodology......................................................................133 10.3. Sampling Considerations ........................................................................................136 10.4. Data Collection .......................................................................................................139 10.5. Results and Discussion ...........................................................................................144 CHAPTER 11: HSM CALIBRATION OF RURAL TWO-LANE THREE-LEG UNSIGNALIZED INTERSECTIONS ............................................................................151 11.1. Introduction and Scope ...........................................................................................151 11.2 Data Requirements for Calibration ..........................................................................151 11.3. HSM Crash Prediction Methodology......................................................................156 11.4. Sampling Considerations ........................................................................................158 11.5. Data Collection .......................................................................................................161 11.6.