When driving on our daily route, we may often become tired, even more so if we spend prolonged periods behind the wheel. The Insurance Information Institute reported 4,111 motor fatalities and 50,000 injuries between 2013 and 2017 directly related to driver fatigue. These are sobering figures, and you may wonder why driving a car makes people so tired?
Here are 4 reasons why car travel is so tiring:
- Going against natural circadian rhythms.
- Sleep deprivation and driver fatigue.
- Monotonous driving may cause driver fatigue.
- Car vibrations make drivers sleepy.
- Signs of driver fatigue.
- How to stay safe on the road.
These factors enhance driver fatigue and result in “drowsy driving,” which is a dangerous condition in terms of road safety. Driver fatigue is a dangerous condition and a very real problem in terms of road safety, and understanding the factors behind driver fatigue may help you to prevent fatigue-related accidents and injuries. Keep reading to find out why car travel is so tiring.
1. Going Against Natural Circadian Rhythms
Research has shown that driver fatigue correlates strongly with the driver’s circadian rhythms.
Circadian rhythms are the natural physical, mental and behavioral responses of most living things, including humans. These responses are biological processes that respond to dark and light within a 24-hour cycle.
A clinical study found that the 15 test subjects who performed a 6-hour on-road driving test showed more significant driver fatigue levels at certain hours with the 24-hour circadian cycle. The study found that driving duration and circadian rhythms considerably affected driver fatigue levels and corresponding steering and lane positioning capabilities.
The experiment results showed that drivers were more likely to feel tired between 2 pm and 4 pm and 2 am and 4 am, where the driver’s ability to stay in their designated lane showed significant impairment.
2. Sleep Deprivation and Driver Fatigue
When a driver is sleep-deprived and takes the wheel of a car, the condition of drowsy driving can be a dangerous undertaking. There are several reasons why a driver may be sleep-deprived, but most commonly, the driver has not slept enough, but it may also be due to:
- Untreated sleep disorders
- Shift work
Drowsy driving affects one’s ability to drive safely, even if you don’t necessarily fall asleep at the wheel. It makes drivers less attentive, slows reaction time, and affects their decision-making ability.
Studies suggest that drivers who snored at night or had less than 6 hours of sleep a night were most likely to suffer from drowsy driving or fall asleep at the wheel.
3. Monotonous Driving May Cause Driver Fatigue
Studies suggest that driving on monotonous terrain causes a cognitive underload, and the resulting lack of stimulation reduces a driver’s alertness. This lack of mental engagement may even induce more fatigue than drivers negotiating challenging terrain for long periods.
The study found that test subjects with more significant speed increases and decreases showed less driver fatigue than those with a more constant speed throughout the test.
Through pupil diameter tests, the rescuers found the pupil diameter became smaller as fatigue progressed in test subjects with minor speed variations. Through EEG tests, they also found that tired drivers exhibited a smaller EEG algorithm between Alpha brain activity and the Theta state of drowsiness.
The study showed that driver fatigue correlates to monotonous travel with minor speed variations and that drivers may increase alertness and reduce fatigue by self-regulating their driving speed variances.
4. Car Vibrations Make Drivers Sleepy
There is evidence to suggest that the low-level vibration a driver experiences may induce drowsiness and impaired concentration. In a clinical study of 15 participants, researchers found a direct correlation between vibration and sleepiness in a simulated driving experiment.
The laboratory-controlled study found changes in heart rate viability which indicated the mental effort of the brain to maintain alertness when experiencing low-level vibration. The researchers found that the test subjects showed signs of drowsiness even only 15 minutes into the test, which increased at the 30 minutes mark.
At this stage, the test subjects had to use substantial effort to maintain alertness.
At 60 minutes, the test subjects’ drowsiness showed a significant peak. The control subjects performing the same exercise on a non-vibrating set showed little to no sleepiness under the same driving conditions.
Tiredness caused by vibration makes it harder for test subjects to perform mental tasks psychologically. The test subject’s body’s nervous system is then activated to compensate for the drowsiness, which causes corresponding changes in their heartbeat.
Signs of Driver Fatigue
A rather sobering report from the Centers for Disease Control and Prevention (CDC) reveals that sleep-deprived drivers perform as poorly on the road as inebriated ones. If you have been awake for 24 hours it is equal to a blood alcohol content of 0.10%, which is higher than the legal limit in all states of the US.
Furthermore, some sleep disorders are unknown to a driver, which may render them unaware of their drowsy driving predicament. You should be aware of the signs that you may be suffering from driver fatigue which include these signs:
- Blinking and yawning frequently.
- Difficulty recalling the past few miles of travel.
- Missing turnoffs and exits.
- Drifting from your allocated lane.
- Hitting the curb or rumble strip.
If you experience the above symptoms, you should stop driving at the nearest safe stop and address your fatigue.
Engage in frequent rest stops and leg stretches and keep yourself well hydrated, and eat often.
A 2012 study found that a single cup of coffee can help combat the effects of drowsy driving, but this should be a temporary fix while you address the underlying issues. After all, extending a deadline is less critical than endangering your safety and the other drivers on the road.
How To Stay Safe On the Road
With evidence that fatigued drivers may be as dangerous as drunk drivers on the road, you should always be vigilant about drowsy driving.
Be especially cautious in the hours between 2 pm to 4 pm and 2 am to 4 am and try to vary a monotonous route with safe speed variations and frequent leg stretches. It is far better to arrive at your destination late than not to arrive at all.
- III: Facts+Statistics: Drowsy Driving
- SagePub Journals: Effect of Circadian Rhythms and Driving Duration on Fatigue Level and Driving Performance of Professional Drivers
- CDC: Drowsy Driving: Asleep at the Wheel
- NCBI: The Relationship Between Drivers’ Cognitive Fatigue and Speed Variability During Monotonous Daytime Driving
- Taylor Francis Online: The effects of physical vibration on heart rate variability as a measure of drowsiness
- NCBI: Effects of coffee on driving performance during prolonged simulated highway driving