Abstract
This chapter provides an overview of the epidemiological literature on the association between driver distraction and risk of crash. The types of distracting activities that have been studied to date are examined, resultsare summarized, and future directions for study are discussed. The chapter begins with a definition of risk, an explanation of the hierarchy of epidemiological evidence, and a discussion about the types of study designs used by epidemiologists to identify whether driver distraction is a risk factor for having a crash.