I. INTRODUCTION

Kentucky in 1998 and Louisiana in 1999 repealed their laws requiring motorcycle helmet use by all riders. These actions follow recent helmet law repeals in Arkansas and Texas that took place in 1997.

This report examines data from Kentucky and Louisiana to assess the effects of the helmet law repeals on helmet use and motorcyclist fatalities and injuries. Following this introduction, the report is organized as follows:

• Chapter II, Background, describes the legislative history of motorcycle helmet laws in the U.S. and reviews the literature on the effects of helmet use and helmet use laws.
  
  
• Chapter III, National Trend, provides national data on trends in motorcycle registrations, travel and casualties.
  
  
• Chapter IV, Effects of the Law Change in Kentucky, describes the effect of Kentucky's law change on helmet use, fatalities, injuries and casualty rates per motorcycle registrations.
  
  
• Chapter V, Effects of the Law Change in Louisiana, provides similar descriptions for Louisiana.
  
  
• Chapter VI, Crash Descriptions, presents narrative descriptions of the fatal motorcycle crashes that took place in Kentucky and Louisiana immediately following the helmet law changes in these two states.
  
  
• Chapter VII, Discussion, briefly discusses the finding of the study.
  
  
• Chapter VIII, References.
  
  
• Appendix, State Helmet Law History, summarizes the history of motorcycle helmet laws in each state.