Commercial Driver Safety Risk Factors (CDSRF) June 2020 FOREWORD The objective of this study was to examine a wide array of driver and situational factors that impact commercial motor vehicle (CMV) safety. The study evaluated the prevalence of these factors as well as their relationship to being involved in a crash or moving violation in a diverse sample of over 21,000 truck drivers. The goal was to identify and prioritize driver individual differences with respect to risk factors. Primarily, these risk factors consisted of personal factors, such as demographic characteristics, medical conditions, personal attitudes, and behavioral history. The study identified risk factors by linking the characteristics of individual drivers with their driving records, especially the occurrence or absence of crashes, during the duration of the study. The prospective study design afforded the opportunity to observe these drivers for up to 3 years using a combined dataset from carrier and national sources. This report documents the methods, data analyses, results, and conclusions involved in successfully conducting this study and evaluating the data. NOTICE This document is disseminated under the sponsorship of the U.S. Department of Transportation (USDOT) in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document. The contents of this report reflect the views of the contractor, who is responsible for the accuracy of the data presented herein. The contents do not necessarily reflect the official policy of the USDOT. This report does not constitute a standard, specification, or regulation. The U.S. Government does not endorse products or manufacturers named herein. Trademarks or manufacturers’ names appear in this report only because they are considered essential to the objective of this report. QUALITY ASSURANCE STATEMENT The Federal Motor Carrier Safety Administration (FMCSA) provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FMCSA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement. Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. FMCSA-RRR-17-014 4. Title and Subtitle 5. Report Date Commercial Driver Safety Risk Factors (CDSRF) June 2020 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. Hickman, Jeffrey; Mabry, J. Erin; Marburg, Laurel; Guo, Feng; Huiying, Mao; Hanowski, Richard; Whiteman, Joel; Herbert, William. 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Virginia Tech Transportation Institute, Blacksburg, VA Road Ready, Inc., Springdale, AR 11. Contract or Grant No. 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered U.S. Department of Transportation Final Report, September 2010–January Federal Motor Carrier Safety Administration 2017 Office of Analysis, Research, and Technology 1200 New Jersey Ave. SE 14. Sponsoring Agency Code Washington, DC 20590 FMCSA 15. Supplementary Notes Contracting Officer’s Representative: Theresa Hallquist 16. Abstract The objective of this study was to prospectively examine a wide array of driver personal and situational factors to determine the prevalence of these factors as well as their relationship to being involved in a crash. This study involved the collection of driver medical, demographic, and other personal factors to examine the relationship between these factors with various safety outcomes. Interested drivers completed initial study materials during a driver orientation session with the participating carrier at one of eight different recruitment sites across the United States. Safety outcomes included crash data from the participating carrier and crashes and moving violation convictions from national datasets. Depending on the analysis, exposure included the driver’s tenure at the participating carrier during the study or the amount of time under observation during the study. Data from over 21,000 drivers were collected, and 20,753 of these drivers were included in the analyses. Many of the prevalence rates for several of the medical conditions were similar to or above the U.S. averages. In general, those receiving treatment for a medical condition were no riskier in terms of safety outcomes than drivers without the medial condition and, in several cases, were less risky than those who did not have the medical condition. When there was an increase in risk in one or more of the safety outcomes, it was usually associated with the driver not receiving treatment or the driver not being clinically diagnosed with the medical condition (and thus not receiving treatment). 17. Key Words 18. Distribution Statement Commercial motor vehicle, medical conditions, crash No restrictions risk, prospective, life experiences, demographics 19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price Unclassified Unclassified 231 Form DOT F 1700.7 (8-72) Reproduction of completed page authorized. SI* (MODERN METRIC) CONVERSION FACTORS Approximate Conversions to SI Units Symbol When You Know Multiply By To Find Symbol Length in inches 25.4 millimeters mm ft feet 0.305 meters m yd yards 0.914 meters m mi miles 1.61 kilometers km Area in² square inches 645.2 square millimeters mm² ft² square feet 0.093 square meters m² yd² square yards 0.836 square meters m² ac Acres 0.405 hectares ha mi² square miles 2.59 square kilometers km² Volume (volumes greater than 1,000L shall be shown in m³) fl oz fluid ounces 29.57 milliliters mL gal gallons 3.785 liters L ft³ cubic feet 0.028 cubic meters m³ yd³ cubic yards 0.765 cubic meters m³ Mass oz ounces 28.35 grams g lb pounds 0.454 kilograms kg T short tons (2,000 lb) 0.907 megagrams (or “metric ton”) Mg (or “t”) Temperature (exact degrees) °F Fahrenheit 5(F-32)/9 or (F-32)/1.8 Celsius °C Illumination fc foot-candles 10.76 lux lx fl foot-Lamberts 3.426 candela/m² cd/m² Force and Pressure or Stress lbf poundforce 4.45 newtons N lbf/in² poundforce per square inch 6.89 kilopascals kPa Approximate Conversions from SI Units Symbol When You Know Multiply By To Find Symbol Length mm millimeters 0.039 inches in m meters 3.28 feet ft m meters 1.09 yards yd km kilometers 0.621 miles mi Area mm² square millimeters 0.0016 square inches in² m² square meters 10.764 square feet ft² m² square meters 1.195 square yards yd² Ha hectares 2.47 acres ac km² square kilometers 0.386 square miles mi² Volume mL milliliters 0.034 fluid ounces fl oz L liters 0.264 gallons gal m³ cubic meters 35.314 cubic feet ft³ m³ cubic meters 1.307 cubic yards yd³ Mass g grams 0.035 ounces oz kg kilograms 2.202 pounds lb Mg (or “t”) megagrams (or “metric ton”) 1.103 short tons (2,000 lb) T Temperature (exact degrees) °C Celsius 1.8c+32 Fahrenheit °F Illumination lx lux 0.0929 foot-candles fc cd/m² candela/m² 0.2919 foot-Lamberts fl Force and Pressure or Stress N newtons 0.225 poundforce lbf kPa kilopascals 0.145 poundforce per square inch lbf/in² * SI is the symbol for the International System of Units. Appropriate rounding should be made to comply with Section 4 of ASTM E380. (Revised March 2003, Section 508-accessible version September 2009.) ii TABLE OF CONTENTS LIST OF ACRONYMS, ABBREVIATIONS, AND SYMBOLS............................................ xii EXECUTIVE SUMMARY ....................................................................................................... xiii Data Entry and Reduction .......................................................................................... xiv 1. INTRODUCTION.................................................................................................................1 1.1 BACKGROUND ...........................................................................................................1 1.1.1 Commercial Motor Vehicle Driver Demographics ........................................... 1 1.1.2 Crashes and Violations ..................................................................................... 1 1.1.3 Driver Factors and Crash Risk .......................................................................... 2 1.1.4 Environmental and Work Factors and Crash Risk ............................................ 2 1.1.5 Situational Factors and Crash Risk ................................................................... 3 1.2 SUMMARY ...................................................................................................................3 2. DATA COLLECTION MATERIALS ................................................................................5 2.1 MEDICAL EXAMINATION REPORT FOR COMMERCIAL DRIVER FITNESS DETERMINATION ......................................................................................................5 2.2 BRIEF MEDICAL EXAM ............................................................................................5 2.3 INITIAL DRIVER SURVEY ........................................................................................6 2.3.1 Demographic Information ................................................................................. 6 2.3.2 Epworth Sleepiness Scale ................................................................................. 6 2.3.3 Berlin Questionnaire ........................................................................................