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Drowsy driving is a widespread issue among motorists in the United States. According to the National Highway Traffic Safety Administration (NHTSA), drowsy driving led to roughly 72,000 accidents, 44,000 injuries and 800 deaths in 2013 alone.
This article will explore some of the key warning signs and risk factors associated with drowsy driving, as well as some prevention tips to help you avoid getting behind the wheel when you are sleep-deprived. First, let’s look at the way ‘drowsy driving’ is currently defined and evaluated by both the scientific and law enforcement communities.
Drowsy driving, also referred to as ‘driver fatigue’, occurs when someone is too tired to operate a motor vehicle and, in turn, puts themselves, their passengers and other motorists in danger. Some of the most common causes of drowsy driving include the following:
The effects of drowsy driving will vary from person to person. Most fatigued drivers have slower reaction times, and often experience short-term memory loss while behind the wheel. Drowsiness has also been linked to overly aggressive driving.
The following statistics highlight the scope of drowsy driving as a nationwide problem:
However, it should be noted that these statistics can be somewhat misleading because drowsy driving can be mistaken for other causes, such as distracted driving or driving under the influence of drugs and/or alcohol. As a result, drowsy driving cases often go unreported.
Investigators can use certain clues to pinpoint a high likelihood of drowsy driving at accident scenes. Most accidents involve single cars with serious or fatal injuries, and there are usually no skid marks or other signs that the driver attempted to avoid the collision. And, not surprisingly, most drowsy driving incidents occur between the hours of 12am and 7am – when we are biologically programmed to be sleepy.
Although many states have enacted or are currently pursuing laws designed to crack down on drowsy driving, there are no blood or breath tests that law enforcement officers can administer to evaluate motorists for this condition. Police may stop a car for general reckless driving, but in general people caught for drowsy driving face less severe penalties than drunk drivers.
Preventing drowsy driving is also difficult at the agency level. Many roads feature rumble strips, or sequences of plastic bumps along the shoulder designed to alert drivers when their vehicle leaves the roadway. Frequently spaced rest areas can also cut down on driver fatigue. Additionally, drowsy driving is a citable driving infraction in most states – although these are much less severe than penalties for drunk driving. Authorities today stress that the ultimate responsibility for preventing drowsy driving falls on individual drivers.
Every driver is susceptible to drowsy driving, but this issue is more commonplace with certain groups. Men, for instance, are more likely to be involved in a drowsy driving accident than women; this trend spans all age brackets. Other groups considered at-risk for drowsy driving include the following:
Drivers between the age of 18 and 29 are considered especially prone to drowsy driving for multiple reasons. For one, younger drivers simply do not get drowsy in the same way as older individuals. This is due to the high-functioning sleep cycle of teenagers and young adults; they are able to resist becoming drowsy more easily, but they are also at risk higher of suddenly falling asleep without warning.
Sleep deprivation is another factor. While most adults require seven to eight hours of nightly sleep, teenagers and young adults need at least nine in order to achieve the same levels of daytime functionality. However, the average young person gets between five and seven hours of sleep on a nightly basis. These one to three lost hours per night can accumulate with each passing day. This buildup is known as sleep debt, and by the end of a standard five-day week, the average young person has accrued a sleep debt of 10 hours. This puts them at risk for falling asleep while driving, just as the weekend arrives.
Studies have also linked high rates of drowsy driving to the typically early schedules of young people who work or attend school. The Journal of Clinical Sleep Medicine noted a connection between car accidents and students who begin their day before 7am, and a similar study noted that vehicular crash rates involving teen drivers dropped 16.5% after classes shifted to later start times. Additionally, young people are biologically programmed to stay up later, and high school and college students are often required to study past their normal bedtimes. Many jobs popular among teens and people in their 20s include late or shift work schedules, as well.
It is believed that drivers between the age of 18 and 29 account for more than half of all drowsy driving accidents in the United States. The table below looks at the high likelihood of a drowsy driving accident involving young people, compared to other age groups. This data comes from a poll published by the National Sleep Foundation.
|Age Group||Likelihood of Being Involved in a Drowsy Driving Accident|
|18 to 29||71%|
|30 to 64||52%|
|65 and older||19%|
Young people are encouraged to adopt a healthy sleep schedule in order to reduce their risk of drowsy driving. Lifestyle choices are also key. Using tobacco, consuming alcohol or drugs and using electronic devices at night are some of the leading causes of sleep deprivation among young people.
According to the the Bureau of Labor Statistics (BLS), roughly 15% of the country’s full-time wage and salary workers follow a shift work schedule. Shift work is currently defined as any work schedule that falls outside the standard business day of 9am to 5pm. Shift work may refer to swing shifts, which usually begin in the mid-afternoon and end at midnight or later; and graveyard shifts, which typically span from late evening to early morning. Shift work also includes shifts that cover 20 to 40 consecutive hours; these schedules are commonly found in industries where round-the-clock personnel are needed, such as healthcare, law enforcement and fire protection.
A study by the National Institute for Occupational Safety and Health noted that car crashes account for roughly 22% of all work-related deaths ? and drowsy driving is considered the leading cause for 7% of these fatalities. Drowsy driving has also been noted in particular industries where shift work is common. For example, medical interns with shifts that span 24 hours or longer are more than twice as likely to be involved in a vehicular accident, and five times as likely to experience a ‘near-miss’ incident while driving to or from work.
There are several ways for shift workers to mitigate the risk of drowsy driving. Carpooling and ride-sharing will reduce their time behind the wheel each week. Shift workers are also discouraged from taking lengthy or overtime shifts if they plan on driving themselves to and from work; employees who work more than 60 hours per week are 40% more likely to be involved in a drowsy driving incident.
For more information on the effect that shift work can have on sleep, check out our guide to shift work sleep disorder.
Commercial drivers are considered particularly at-risk for drowsy driving. Many of these employees follow shift work schedules, and their job requires long days, and often nights, behind the wheel. Roughly 13% of commercial drivers involved in a large truck collision report being drowsy behind the wheel.
The Federal Motor Carrier Safety Administration (FMCSA) discourages commercial drivers from operating their vehicles between the hours of 12am to 6am, and also 2pm to 4pm; these are periods when we naturally begin to get drowsy. Napping for up to 45 minutes, and then allowing an extra 15 minutes to wake up, can help drivers restore their energy during break periods. They can also increase their alertness by following a proper diet and abstaining from sleep-inducing medications.
The FMCSA also warns of ‘tricks of the trade’ that commercial drivers use to stay awake. These include using tobacco, consuming caffeine, turning up the radio and/or rolling down the window. Although these activities can provide momentary bursts of renewed energy, none of them have much lasting power. This can quickly lead to drowsiness. Rather than relying on these temporary tactics, it’s important for drivers to recognize the warning signs of drowsiness, and get off the road as soon as they begin to experience these symptoms.
Business trips involving long journeys can take a toll on your body and affect your circadian rhythm. This is especially true of international travel, since returning home typically involves readjusting to the local time. The transition period, commonly referred to as jet lag, may include periods of sleeplessness and/or fatigue. Flights that depart or arrive in the early morning or late night hours can also impact your sleep schedule. For these reasons, pilots, flight crews and other airline personnel are also at risk for drowsy driving after their shifts have ended.
Business travelers are encouraged to commute to and from airports using taxis or car services. For airline employees, a carpooling or ride-sharing schedule may also be feasible. You can also mitigate the effects of jet lag prior to your trip by gradually adjusting to the local time of wherever you’re headed. During long flights, also try to follow a sleep schedule that aligns with the time zone of your destination. Abstaining from alcohol, tobacco and other stimulants like caffeine while in the air can also ease the jet lag process.
Many sleep disorders can cause drowsiness. These include the following:
Sleep disorders affect millions of Americans, but they often go undiagnosed. A driver with an undiagnosed sleep disorder is at high risk of being involved in a drowsiness-related accident. Alternatively, many people who are diagnosed with sleep disorders take sleep-inducing medication to help them get enough rest on a daily basis. These medications also increase the likelihood of a drowsy driving incident.
If you live with a sleep disorder or suspect you may have one, it’s important to speak with a physician as soon as possible. People with sleep disorders who must commute long distances are discouraged from taking medications with soporific side effects.
Now that we have discussed some of the risk factors associated with drowsy driving, let’s look at some preventative measures you can take to reduce your likelihood of being involved in a drowsy driving collision.
Remember: it is dangerous and against the law to pull your car onto the shoulder of a freeway or highway in order to sleep.
Alcohol use is another important consideration. The effects of alcohol on humans vary from person to person, and often depend on factors like weight and medical history. The general rule of thumb is that 12 ounces of beer, five ounces of wine and 1.5 ounces of liquor are all roughly equivalent, and that more than three individual servings of any combination over the course of a few hours will cause intoxication. However, even one serving of alcohol can cause you to become drowsy.
Additionally, it’s important for people who regularly take medication to read the warning labels, even if they have been prescribed for a non-sleep-related condition. The following medication types are designed to induce drowsiness to some extent:
Finally, understanding your own individual symptoms of drowsy driving is critical when you are on the road. If you are concerned about your fatigue level and worried that drowsiness may be impacting your driving, here are a few considerations to make:
If you answered yes to any of these questions, then you should get off the road immediately and refrain from driving until you are properly rested.
No matter how roads are engineered to cut down on driver fatigue or vehicles are programmed to provide drowsiness alerts, the responsibility for safe and vigilant driving will always fall on the driver. By following the guidelines laid out in this article, you can make the road safer for you, your passengers and other drivers.
For more information about drowsy driving identification and prevention, check out the following online resources: