Fatigue, or drowsiness, is known to degrade driving performance by slowing reaction time, impairing judgment and situational awareness, and increasing attentional lapses as well as the occurrence of microsleeps (Rosekind, 2012). Operator drowsiness, sleepiness, or fatigue (hereafter referred to as drowsiness) has been documented as a contributing factor in aviation, maritime, and traffic crashes. However, in comparison to some other highway safety problems such as drunk and distracted driving, drowsy driving has received much less attention. Estimates of the prevalence of self-reported drowsy driving have been remarkably consistent. A national survey of drivers ages 16 and older conducted by the National Highway Traffic Safety Administration (NHTSA) in 2002 found that 37% of drivers reported having ever “nodded off for at least a moment or fallen asleep while driving,” including 4% who had done so in the past month (Royal, 2003). A survey of residents of 19 states and the District of Columbia conducted by the Centers for Disease Control and Prevention (CDC) in 2009-2010 found that 4 percent of drivers aged 18+ reported having fallen asleep while driving in the past 30 days (CDC, 2013). Another national survey conducted by the AAA Foundation for Traffic Safety in 2010 found that 41% of drivers reported having ever fallen asleep or nodded off while driving, including 4% who had done so in the past month (Tefft, 2010). Most previous studies of the prevalence of crashes that involved driver drowsiness analyzed data derived from police reports found that drowsiness was only cited as a contributing factor in 1-4% of crashes (Knipling & Wang, 1994; Knipling & Wang, 1995; Wang, Knipling, & Goodman, 1996). However, more recent studies have estimated that the actual prevalence is likely much higher. The AAA Foundation analyzed data from a representative sample of crashes that were subject to in-depth investigations, found that the drowsiness status of nearly half of all drivers was reported as unknown, developed a statistical model to estimate the proportion of those drivers who were drowsy, and estimated that 7% of all crashes in which a vehicle was towed, 13% of crashes that resulted in a person being admitted to a hospital, and 17% of fatal crashes in years 1999-2008 involved a drowsy driver (Tefft, 2010). An update of that study, based on data from 2009-2013, estimated that 6% of all crashes in which a passenger vehicle was towed, 13% of crashes that resulted in a person being admitted to a hospital, and 21% of fatal crashes involved a drowsy driver (Tefft, 2014). The purpose of the present study was to provide updated estimates of the prevalence of selfreported drowsy driving using data from a nationally-representative survey of drivers conducted in 2015. (Author/publisher)
Samenvatting