Drowsy driving kills. It claimed 856 lives in 2014. NHTSA is working with the Centers for Disease Control and Prevention and the National Institutes for Health to expand our understanding of drowsy driving so that we can reduce related deaths and injuries and help people avoid being a drowsy-driving statistic.
Scope of the Problem
Precise counts of crashes caused by drowsy driving are not yet possible. Crash investigators can look for certain clues that drowsiness was likely to have contributed to driver error, but these clues are not always identifiable or conclusive. In lieu of consistent and conclusive evidence, researchers have used various methods to estimate the overall number of crashes or crash fatalities caused by driver drowsiness. These methods range from counts of crash reports where police-reports indicate drowsiness as a contributing factor, to statistical estimates based on crash reports and surveys of self-report crashes or driving experience.
In 2014 there were 846 fatalities (2.6% of all fatalities) recorded in NHTSA’s FARS database that were drowsy-driving-related. These reported fatalities (and drowsy-driving crashes overall) have remained largely consistent across the past decade. Between 2005 and 2009 there was an estimated average of 83,000 crashes each year related to drowsy driving. This annual average includes almost 886 fatal crashes (2.5% of all fatal crashes), an estimated 37,000 injury crashes, and an estimated 45,000 property damage only crashes.
There is ongoing research and discussion about how best to measure the impact of drowsy driving on crashes. A variety of research approaches and data indicate that traditional measures of drowsy driving may significantly underestimate the prevalence of the issue. Researchers have inferred the existence of additional drowsy-driving crashes by looking for correlations with related factors such as the number of passengers in the vehicle, crash time and day of week, driver sex and crash type. One such study from the AAA Foundation for Traffic Safety analyzed data from NHTSA's National Automotive Sampling System (NASS) Crashworthiness Data System (CDS). By using a multiple imputation methodology they estimated 7 percent of all crashes and 16.5 percent of fatal crashes involved drowsy driving. If this estimate is accurate, it suggests that more than 5,000 people died in drowsy-driving-related motor vehicle crashes across the United States last year. The 2009 Massachusetts Special Commission on Drowsy Driving, based on a different research methodology, estimated that there could be as many as 1.2 million crashes, 8,000 lives lost, and 500,000 injuries due to drowsy driving each year.
Crashes and Fatalities
Crashes caused by drowsy driving often exhibit a set of common factors. Although sleepiness can affect all types of crashes during the entire day and night, drowsy-driving crashes most frequently occur between midnight and 6 a.m., or in the late-afternoon – both times when there are dips in your circadian rhythm (the internal human body clock that regulates sleep). Many drowsy-driving crashes also involve only a single vehicle, with no passengers besides the driver, running off the road at a high rate of speed with no evidence of braking. Drowsy-driving crashes also frequently occur on rural roads and highways.
Avoid Driving Drowsy
- The best countermeasure to drowsy driving is to get enough rest on a daily basis. Sleep is the only true preventative measure against the risks of drowsy driving. Make it a priority to get 7-8 hours of sleep per night. For more information on healthy sleep, see the National Heart, Lung, and Blood Institute website.
- Before the start of a long family car trip, get a good night’s sleep, or you could put your entire family and others at risk.
- Many teens do not get enough sleep at the same time that their biological need for sleep increases, thereby increasing the risk of drowsy-driving crashes, especially on longer trips.
- Avoid drinking any alcohol before driving. Consumption of alcohol interacts with sleepiness to increase drowsiness and impairment.
- If you take medications that could cause drowsiness as a side effect, use public transportation when possible. If you drive, avoid driving during the peak sleepiness periods (midnight – 6 a.m. and late afternoon).
- If you must drive during the peak sleepiness periods, stay vigilant for signs of drowsiness, such as crossing over roadway lines or hitting a rumble strip, especially if you’re driving alone.
- Drinking coffee or energy drinks alone is not always enough. They might help you feel more alert. However, the effects last only a short time, and you might not be as alert as you think you are. If you drink coffee and are seriously sleep-deprived, you still may have “micro sleeps” or brief losses of consciousness that can last for four or five seconds. This means that at 55 miles per hour, you’ve traveled more than 100 yards down the road while asleep. That’s plenty of time to cause a crash.
- If you start to get sleepy while you’re driving, drink 1-2 cups of coffee and pull over for a short 20-minute nap in a safe place, such as a lighted designated rest stop. This has been shown to increase alertness in scientific studies but only for short time periods.
Drowsy Driving Prevention Week. Each November, the National Sleep Foundation conducts Drowsy Driving Prevention Week in an effort to reduce the number of drowsy-driving crashes.
Centers for Disease Control & Prevention (CDC)
- Dangers of Drowsy Driving
- Morbidity and Mortality Weekly Report (January 4, 2013) Drowsy Driving – 19 States and the District of Columbia 2009-2010
- Morbidity and Mortality Weekly Report (July 4, 2014) Drowsy Driving and Risk Behaviors
Food & Drug Administration (FDA)
- Caution: Some Over-the-Counter Medicines May Affect Your Driving
- FDA Basics Webinar (June 2014): Over-the-Counter Medicines and Driving
Federal Highway Administration (FHWA)
- Rumble Strips: A Wake-Up Call for Drowsy Drivers
- State DOT Report: Utah Department of Transportation Research & Development Division, A Safety Analysis of Fatigue and Drowsy Driving in the State of Utah
Federal Motor Carrier Safety Administration (FMCSA)
National Institutes of Health (NIH) National Center on Sleep Disorders Research and Office of Prevention, Education, and Control
- Educating Youth About Sleep and Drowsy Driving (PDF 981KB)
National Institute for Occupational Safety and Health (NIOSH)
- Quick Sleep Tips for Truck Drivers (PDF 1.9MB)
National Transportation Safety Board (NTSB)
Volpe National Transportation Systems Center
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