Sleep Deprivation and Traffic Accidents

Ten years ago, a former colleague of mine, a fine teacher and person, was tragically killed in a car accident in British Columbia. He was on vacation with his daughter who miraculously survived the accident. What happened was a classic case of sleep deprivation: my friend was anxious to make his way to a chosen destination and despite his fatigue and the fact that he had been on the road for over 6 hours, he made the decision to drive through the night. He never made it there.

That there is a direct correlation between sleep deprivation and traffic accidents cannot be disputed. In 1998, 24,318 deaths were cited from accidents related to sleep deprivation in the US. There were as well 2, 474,430 disabling injuries resulting from accidents where decreased mental efficiency and attentiveness due to sleep loss was the major causative factor. In fact, a major review conducted in 1996 suggested that the oil spill of the Exxon Valdez, the destruction of the space shuttle Challenger, the nuclear accident at Chernobyl( costing over 50,000 lives) and the near nuclear accidents at the Three Mile Island and Peach Bottom reactors were all associated with sleep deprivation of the personnel involved.

Sleep deprivation is often caused by sleep disorders which are unknown to the subjects themselves. Sleep apnea, for example, is a common cause for sleep deficit. A study at the Sleep Disorders and Research Center of Stanford University Medical School showed that truck drivers identified with sleep disordered breathing had a two-fold higher accident rate than drivers without sleep-disordered breathing. Sleep disordered breathing, commonly known as sleep apnea, affects 15 million people in the United States. This condition, characterized by suffocation and oxygen deprivation which wake the subjects up several times in the course of the night, is responsible for daytime sleepiness and fatigue. Put these subjects on the highway and we have a recipe for disastrous traffic accidents.

Perhaps an examination of the influence sleep deprivation has on our mental acuity and performance level can shed light on how we can protect ourselves and others from the disastrous consequences of sleep fatigue.

What happens to you when you are sleep deprived? According to the Traffic Research Center, these are the influences of sleep deprivation on performance:

a) Slower reaction time: sleeplessness slows down your reflexes; reaction time slows down, preventing you from stopping in times of danger.

b) Decrease in concentration levels: When you are overly tired, your attention span decreases. Most people are subject to a decrease in attention every 90-120 minutes; however, sleepiness makes this decrease even worse and it can cause accidents when you fall asleep at the wheel.

c) Disorder in information processing: Sleepiness is very much like being under the influence of alcohol or drugs. When you are sleepy, your mental and psychomotor skills diminish. In one study, a group of subjects were kept awake for 28 hours; another group was given alcoholic drinks every half hour. When both groups were tested for hand-eye coordination, the ones who were sleep deprived performed equally bad as the ones with 0.5 blood alcohol level.

What are the factors that have a direct effect on a driver's tiredness?

a) The amount of time the driver has been on the road. When a driver has been on the road for 8 or more hours, his driving performance is impaired. The risk of accidents increases.

b) The amount of sleep the driver had the night before. Not having any sleep for 16 hours has a serious impact on driving performance. Research shows that the sleeping period of drivers who are involved in road accidents are shorter than the ones of those who had sufficient sleep.

c) Sleep disorders and Obesity. Sleep disorders like sleep apnea or narcolepsy in truck drivers are a major risk factor. In the same Stanford University Study mentioned above, even weight can seriously affect the frequency of traffic accidents. Obese drivers with a body mass more than 30 kg also presented a two-fold higher accident rate than non-obese drivers.

d) Environmental factors. The lack of resting and parking facilities for drivers is another factor that contributes to the accident rate.

What can we do to ensure that we get adequate sleep?

a) Set up a bedtime ritual—the same time to bed, the same routines like reading in bed or listening to relaxing music.

b) See your doctor if you have snoring or breathing problems, daytime fatigue, morning headaches, night time choking episodes. You could have sleep apnea which can be treated with new devices and technology.

c) If you are overweight, take the steps to bring down your weight. Obesity is a common factor in sleeplessness.

d) Get into a routine of exercise during the day. Do not exercise after 7Pm as the activity could be over stimulating and prevent you from sleeping.

A simple thing like sleep is nothing to be dismissed. More and more studies are revealing a direct link between our nighttime and daytime experiences.