• Drowsy Driving

    Drowsy driving. It doesn't sound serious, does it? Yet, asleep-at-the-wheel and driving-off-the-road accidents are claiming more lives and causing more injury and property damage each year. In fact, drowsy driving is now as dangerous as drinking and driving, based on the injuries, deaths and damages it causes. Whether you actually fall asleep at the wheel, or you have delayed reactions and mistakes in your driving, you are equally at risk for serious results of drowsy driving..

    What Is Drowsiness?

    Your body requires three things: water, food and sleep. You can choose not to drink water until you eventually die. Your body's need to sleep is so strong however; that you can try not to sleep, but your brain will eventually make your body sleep, no matter what you are doing at the time.

    Several factors can cause drowsiness: the time of the body clock, exposure to daylight/darkness, and how long you've been awake. Your body's internal clock (called circadian rhythm) signals you to be sleepy twice a day: first in the evening at bedtime, and again about 12 hours later, during the "siesta" time of the afternoon. The cycle of sunlight and darkness in a day helps set our bodies' internal clock. In addition, the length of time we stay awake can increase our need for sleep (i.e., the longer you stay awake, the more you need sleep).

    Although each person's sleep needs and patterns vary, most adults require an average of eight hours of restful sleep each night. If you are not getting enough sleep, you build up sleep debt. Your sleep continues to grow as you "add on" more and more hours of sleep time. The longer you try to stay awake or the more nights you do not get enough sleep, the drowsier you become and the greater the effect on your mental and physical abilities.

    Excessive sleepiness reduces your alertness and performance. You react more slowly and have more trouble making decisions. You also have a difficult time paying attention, and your memory and coordination are weaker. In fact, people who are drowsy sometimes don't realize that they have these symptoms, making drowsiness that much more dangerous.

    The effects of drowsiness are actually just like the effects of drinking. In many states a blood alcohol concentration (BAC) of .08 is the legal limit for alcohol. A 1997 research study found that being awake for 18 hours produced impairment equal to a BAC of 0.05. After 24 hours of being awake, it jumps to 0.10. Even if you only lose one or two hours of sleep a night, drowsiness can impair your ability to drive at a rate that is higher than the legal alcohol limit.

    This fact is even more disturbing when compared with the average amount of sleep that adults get every night. Sleep studies report that adults do not get the recommended eight hours of restful sleep at night. One study found 64% get less than eight hours and 32% report they get six hours or less. Whether you are severely drowsy only once in your lifetime, or you're sleepy all the time, the consequences can be fatal.

    How Widespread is Drowsy Driving?

    The U.S. National Highway Traffic Safety Administration (NHTSA) cites drowsiness as a factor in 100,000 police-reported crashes annually involving 76,000 injuries and 1,500 deaths. This represents 1%-3% of all police reported crashes and 4% of fatalities.

    Public surveys, however, suggest an even higher rate of drowsy driving. In one survey, 55% of those answering said they had driven while drowsy in the past year. Over a lifetime, 23% said they had fallen asleep but had not crashed, 3% had fallen asleep and crashed, and 2% had crashed when driving while drowsy.
    It is not easy to pinpoint drowsy driving as a cause for an accident because there is no physical test to determine sleepiness (like the Breathalyzer for detecting alcohol levels). Traffic officials are often not trained to look for sleep-related causes and, therefore, may attribute a sleep-related accident to speeding or intoxication. Many states do not have a "fall asleep crash" code on their crash report forms, nor do they have a central database to track such causes.

    There are usually no witnesses to a driver's drowsiness prior to a crash, and drivers themselves don't always realize they are drowsy before they doze off. In fact, drowsy drivers are often more alert after an accident or other sleep-related mistake, which can be misleading since you can't tell how sleepy they were before the incident. When drowsiness is combined with alcohol, often the alcohol is listed as the only cause of an accident. After an accident, many drivers are also reluctant to tell police they were drowsy. With all these factors working against awareness of drowsiness as a cause of car accidents, it is no wonder that official statistics that do exist, however all show that drowsy driving accidents are increasing every year.

    Drowsy drivers need to know more about good sleep habits in order to stop driving while they are sleepy. Sleep debt also needs to be recognized as a serious problem. It is currently overlooked because it is too common.

    What Are The Common Characteristics in Drowsy Driving Accidents?

    Time of Day: As mentioned above, there are two times during a 24-hour period when our body clocks tell us to sleep - at night and during the "siesta" time of the afternoon. These are the two times when most people are naturally sleepy, whether they are getting enough sleep or not. Statistics show that these are also the two most common times for drowsy driving accidents. Most occur between midnight and 8:00 A.M.; the rest typically occur between 1:00 P.M. and 3:00 P.M. If you must drive during these times, make sure you are aware of the risks, and get plenty of rest before hand.
    Single driver: In one study, 82% of reported fall-asleep/drowsy crashes involved someone driving alone. A single driver has no one to interact with and help keep him or her alert. Another person in the vehicle usually will be able to notice when the driver is getting sleepy. In addition, someone driving by him or herself is responsible for doing all the driving, while two or three other people carpooling can rotate when the driver gets sleepy.

    No attempt to avoid crash: Because a drowsy or asleep driver may close his or her eyes for a moment, a common characteristic of drowsy driving accidents is that the driver did not seem to avoid the crash. Because of this, a high percentage of drowsy driving accidents are fatalities. A reported 4% of all motor vehicles fatalities are attributed to driver sleepiness. A sleepy driver is less able than an alert driver to take corrective action prior to a crash, which is shown by the lack of evidence of skid marks or witness accounts of seeing brake lights.

    Who is Most at Risk?

    Young male drivers: In one study of fall-asleep accidents, the driver was under the age of 25 in 55% of the crashes. Seventy-five percent of those drivers were males. Sleepiness may be due to lifestyle of behavior choices, and this group is usually more likely to make choices that cause sleepiness (staying up late, working longer hours).

    Shift workers, business travelers, others experiencing circadian rhythm disorders: Shift workers (people who work overnight) are always trying to sleep when their bodies want to be awake, and to work when their bodies want to sleep. For this reason, they may suffer from body clock (circadian rhythm) disorders where their bodies are programmed for a sleep-wake schedule that differs from their bodies' natural schedule or form what they are used to at home. Any of these circumstances can cause lack of sleep, or poor sleep quality. This can result in excessively sleepy drivers, who may have far less alertness for the task of driving.

    Drivers suffering from cumulative partial sleep deprivation: Some people suffer from cumulative partial sleep deprivation (i.e., they consistently get less than the recommended eight hours of restful sleep per night). They report a high tendency to doze off in many different situations and, therefore, are also at greater risk for drowsy driving incidents. Their sleep debt grows larger over time. As the debt becomes greater, so does their bodies' desire to sleep. They become excessively sleepy, which affects their attention and performance in a variety of tasks, including driving.

    Drivers suffering from acute sleep deprivation: People who have acute sleep deprivation have been awake for many hours (e.g., working all day and making a trip that same night). This lack of sleep has a serious impact on their ability to pay attention and react while driving. One study showed drivers awake for 15 or more hours had four times the risk of a drowsy driving crash. If a driver had been awake for 20 more hours, the risk of crashing increased by 30 times.

    Drivers suffering from untreated sleep disorders: Drivers who have undiagnosed or untreated obstructive sleep apnea syndrome (OSAS), narcolepsy, or other sleep disorders are also at greater risk, because if left untreated, sleep disorders rarely allow the person to get enough restful sleep at night. Because of this, the most common symptom of many sleep disorders is excessive daytime sleepiness. Studies show OSAS occurs in many people and creates a two- to seven-time increase in the rate of drowsy driving crashes.

    Drivers using medications with sleep-inducing side effects: Certain over-the-counter and prescription medication may cause you to be very drowsy. Such medications have warning labels because these effects can certainly impair a driver's attention and ability to react quickly. These medications include: sleeping pills, narcotic pain pills, some antidepressants, tranquilizers, some high blood pressure pills, cold or cough tablets/liquids, and muscle relaxants.

    Drowsy drivers who have consumed alcohol: Alcohol naturally makes you sleep, and it alone can be enough to cause a vehicle crash. However, when combined with excessive drowsiness, its effects are multiplied. Alcohol interacts with sleepiness, greatly lowering mental and physical alertness, and creating a greater amount of swerving and drifting off the road than either alcohol or drowsiness alone. In one driving simulation study, alcohol levels below the legal driving limit produced a higher number of mistakes after four hours of sleep than after eight hours of sleep. In fact, the study found that on four hours of sleep, one beer had the impact that a six-pack had on a well-rested person.

    What are the Signs of Drowsy Driving?

    Below, are a few of the most common signs that a driver is excessively drowsy. If you experience any or all of these signs, you may be at risk for a car accident.
    • You can't remember driving the last few miles
    • You drift from your lane or hit the rumble strip
    • Your attention is weakened and your thoughts wander
    • You find yourself yawning frequently
    • You are unable to focus or keep your eyes open
    • You tailgate or miss traffic signs
    • You catch yourself "nodding off" and have trouble keeping your head up

    How Do We Prevent Drowsy Driving?

    Behavior: The two most effective ways to prevent drowsy driving involve behavior choices. The first is to get a good night's sleep prior to driving. Unfortunately, most people don't think of the effects of drowsy. However, prevention is the best measure, and for that, there is no substitute for sleep. Consistently good sleep habits are the best prevention for drowsy driving.
    The second way to prevent drowsy driving is to stop and sleep when you are feeling drowsy, whether you think you have any signs of drowsy driving or not. When you're drowsy, you are not always aware of your own symptoms of drowsy driving, or you think you can deal with the problem as you continue to drive. If you feel at all tired or sleepy while driving, be safe and stop before your drowsiness is out of control. Even if you think you can handle it, try to remember that it is not easy for drowsy drivers to realize how much danger they're in.
    It is also wise for all drivers to avoid alcohol and medications that impair their ability to drive. Ask your healthcare professional about any medications you take if you do knot know whether they can hinder your driving ability.

    Alerting devices: One of the most effective alerting devices to date is the roadway rumble strip, which is the pattern of grooves along both sides of a highway or freeway. The purpose of a rumble strip is to make enough noise and vibration to wake up a dozing driver if his or her vehicle starts drifting off the road. While rumble strips have been proven to reduce off-road deviations, they are definitely not a cure-all for drowsy driving since drivers are just as likely to drift into oncoming traffic, as they are to drift off the road.
    Some auto manufacturers have been experimenting with the use of in-vehicle devices for keeping drivers alert. These devices are used to keep drivers alert. These devices are intended to monitor driver sleepiness and some include alarms. However, there is insufficient data at this time to prove the effectiveness of such devices. Also, driver dependence on such devices does not address the issue of preventing drowsy driving by getting enough restful sleep. These devices may, in fact, give drowsy drivers a false sense of security - they may feel safer driving while sleepy, trusting these devices to keep them awake.

    Shift work & Jetlag: The best preventive measure for shift workers and their employers is education. Several programs have had success in this area. Reducing the number of times a worker's shift changes, changing shifts forward in time rather than backward, implementing regular rest periods, offering the option of exercise periods, and using bright light can all minimize the effects of shift work on a person's body clock.
    Jet-lagged travelers can adjust their sleeping times prior to their trip to help them adjust (try to use the new sleep/arise times if possible). Rest periods, exercise, and the use of bright light can also be helpful for adjusting to a different time zone.

    Awareness of medical disorders: As mentioned earlier, some drowsy drivers may actually suffer from untreated sleep disorders. The two most common are Obstructive Sleep Apnea Syndrome (OSAS) and narcolepsy. Habitual loud snoring, gasping for air while sleeping, or the stopping of breathing are the most common symptoms of OSAS. OSAS results in many awakenings during the night (even though they may not be remembered) and non-restful sleep. Narcolepsy causes someone to fall asleep rapidly in almost any situation at any time throughout the day. Both sleep disorders should be diagnosed by a sleep specialist.

    Courtesy of the American Academy of Sleep Medicine (http://www.aasmnet.org)

Table of Contents