The Prevalence and Impact of Drowsy Driving

Studies have documented operator drowsiness, sleepiness, or fatigue as causal or contributing factors in aviation, maritime, and trucking accidents. However, estimates of the prevalence of drowsy drivers on the road and of the proportion of motor vehicle crashes that involve drowsy drivers vary widely. This study presents new estimates of the prevalence of drowsy drivers on U.S. roads and of the proportion of crashes that involve a drowsy driver. In a nationally representative telephone survey of U.S. drivers conducted in the spring of 2010, 41.0% of drivers admit to having “fallen asleep or nodded off” while driving at some point in their lives, including 11.0% within the past year and 3.9% in the past month. More than one in four drivers admits to having driven when they were “so sleepy that [they] had a hard time keeping [their] eyes open” within the past month. Examination of data from a nationally-representative sample of crashes that occurred between 1999 and 2008 and involved a passenger vehicle that was towed from the scene shows that 3.9 percent of all of those crashes, 7.7 percent of those that resulted in at least one person being admitted to a hospital, and 3.6 of those that resulted in death involved a driver who was coded as drowsy. However, the attention status of 45% of the drivers in the data was unknown. The statistical technique of multiple imputation was used to take into account additional information about these drivers and the crashes in which they were involved and to estimate the proportion of these drivers who were drowsy. Taking all of these drivers into account, an estimated 7.0% of all crashes in which a passenger vehicle was towed, 13.1% of crashes that resulted in a person being admitted to a hospital, and 16.5% of fatal crashes involved a drowsy driver. © 2010, AAA Foundation for Traffic Safety