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Developing a Method to Identify Horizontal Curve Segments with High Crash Occurrences Using the Haf Algorithm

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Developing a Method to Identify Horizontal Curve Segments with High Crash Occurrences Using the Haf Algorithm Report No. UT-18.02 DEVELOPING A METHOD TO IDENTIFY HORIZONTAL CURVE SEGMENTS WITH HIGH CRASH OCCURRENCES USING THE HAF ALGORITHM Prepared For: Utah Department of Transportation Research Division Submitted By: Brigham Young University Department of Civil and Environmental Engineering Authored By: Mitsuru Saito, Ph.D., P.E. Joseph Browning, EIT Grant G. Schultz, Ph.D., P.E., PTOE Draft Final Report April 2018 DISCLAIMER The authors alone are responsible for the preparation and accuracy of the information, data, analysis, discussions, recommendations, and conclusions presented herein. The contents do not necessarily reflect the views, opinions, endorsements, or policies of the Utah Department of Transportation or the U.S. Department of Transportation. The Utah Department of Transportation makes no representation or warranty of any kind, and assumes no liability therefore. ACKNOWLEDGMENTS The authors acknowledge the Utah Department of Transportation (UDOT) for funding this research, and the following individuals from UDOT on the Technical Advisory Committee for helping to guide the research: Scott Jones, Safety Programs Engineer Jason Richins, Research Project Manager Travis Jensen, Research Project Manager (Consultant) Clancy Black, Traffic & Safety Support (Consultant) Linda Massie, HPMS Coordinator & LRS Manager Anne Ogden, Region 4 Traffic Engineer Ryan Ferrin, Region 2 Traffic Engineer Kelly Jones, Region 2 Traffic Engineer ii Protected Under Title 23 USC 409 TECHNICAL REPORT ABSTRACT 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. UT-18.02 N/A N/A 4. Title and Subtitle 5. Report Date DEVELOPING A METHOD TO IDENTIFY HORIZONTAL CURVE April 2018 SEGMENTS WITH HIGH CRASH OCCURRENCES USING THE 6. Performing Organization Code HAF ALGORITHM 7. Author(s) 8. Performing Organization Report No. Mitsuru Saito, Ph.D., P.E., Joseph Browning, Grant G. Schultz, Ph.D., P.E., PTOE 9. Performing Organization Name and Address 10. Work Unit No. Brigham Young University 5H07841H Department of Civil and Environmental Engineering 11. Contract or Grant No. Provo, UT 84602 17-8512 12. Sponsoring Agency Name and Address 13. Type of Report & Period Covered Utah Department of Transportation Final 4501 South 2700 West Dec 2016 to April 2018 P.O. Box 148410 14. Sponsoring Agency Code Salt Lake City, UT 84114-8410 PIC No. UT16.302 15. Supplementary Notes Prepared in cooperation with the Utah Department of Transportation and the U.S. Department of Transportation, Federal Highway Administration 16. Abstract Crashes occur every day on Utah’s highways. Curves can be particularly dangerous as they require driver focus due to potentially unseen hazards. Often, crashes occur on curves due to poor curve geometry, a lack of warning signs, or poor surface conditions. This can create conditions in which vehicles are more prone to leave the roadway, and possibly roll over. These types of crashes are responsible for many severe injuries and a few fatalities each year, which could be prevented to a large degree. This highlights a need for identification of curves with high crash occurrences. The Horizontal Alignment Finder (HAF) Algorithm created by a BYU team in 2014 was improved to achieve 87-100 percent accuracy in finding curved segments of UDOT’s highways, depending on highway type. A tool was then developed through Microsoft Excel Visual Basic (VBA) to sort through curve and crash data to determine the number of severe and total crashes that occurred along each curve. The tool displays a list of curves with high crash occurrences. The user can sort curves by several different parameters, including various rates and numbers of crashes. Many curves with high crash rates have already been identified, some of which will be shown in this report. This tool will help UDOT determine which highway curves warrant improvement projects. 17. Key Words 18. Distribution Statement 23. Registrant's Seal Crashes, safety, modeling, prediction, Not restricted. Available through: horizontal alignment, curve UDOT Research Division N/A 4501 South 2700 West P.O. Box 148410 Salt Lake City, UT 84114-8410 www.udot.utah.gov/go/research 19. Security Classification 20. Security Classification 21. No. of Pages 22. Price (of this report) (of this page) 118 N/A Unclassified Unclassified iii Protected Under Title 23 USC 409 TABLE OF CONTENTS LIST OF TABLES ........................................................................................................................ vii LIST OF FIGURES ..................................................................................................................... viii LIST OF ACRONYMS .................................................................................................................. x EXECUTIVE SUMMARY ............................................................................................................ 1 1.0 INTRODUCTION .................................................................................................................... 2 1.1 Problem Statement .................................................................................................................2 1.2 Objectives ..............................................................................................................................3 1.3 Scope ......................................................................................................................................3 1.4 Outline of Report ...................................................................................................................3 2.0 LITERATURE REVIEW ......................................................................................................... 5 2.1 Overview ................................................................................................................................5 2.2 Data Collection ......................................................................................................................5 2.2.1 GPS ................................................................................................................................ 5 2.2.2 LiDAR ............................................................................................................................ 6 2.2.3 Visual ............................................................................................................................. 8 2.2.4 Inertial Measurement Devices ....................................................................................... 9 2.3 Methods of Curve Identification ..........................................................................................10 2.3.1 Heading Change ........................................................................................................... 10 2.3.2 Spline Approximation .................................................................................................. 11 2.3.3 Geometric Curve Parameters ....................................................................................... 13 2.4 Other Curve Parameters .......................................................................................................14 2.4.1 Vertical Curves ............................................................................................................ 14 2.4.2 Superelevation .............................................................................................................. 15 2.5 Chapter Summary ................................................................................................................16 3.0 METHODOLOGY ................................................................................................................. 18 3.1 Overview ..............................................................................................................................18 3.2 Calibration ...........................................................................................................................18 3.3 HAF Errors and Improvements ............................................................................................18 3.4 Crash Data Combination ......................................................................................................19 iv Protected Under Title 23 USC 409 3.5 Chapter Summary ................................................................................................................19 4.0 HAF ALGORITHM CALIBRATION PROCESS ................................................................. 20 4.1 Overview ..............................................................................................................................20 4.2 How the HAF Algorithm Works .........................................................................................20 4.3 Calibration Procedures .........................................................................................................21 4.3.1 Determination of Segments to be Used ....................................................................... 21 4.3.2 Comparing Satellite Imagery ....................................................................................... 23 4.3.3 Determining Actual Curve Parameters ........................................................................ 23 4.4 Chapter Summary ................................................................................................................26 5.0 TYPES OF ERRORS IN THE ORIGINAL HAF ALGORITHM ......................................... 28 5.1 Overview ..............................................................................................................................28
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