drowsy driving

Drowsy Driving: Causes and How to Avoid It

by Zutobi · Updated Feb 23, 2022

Driver fatigue, or drowsy driving, is the feeling of being tired, sleepy, or exhausted when driving and is a major cause of crashes. It affects everyone regardless of driving experience, but experienced drivers are often better able to avoid fatigue by knowing when to take a break.

Fatigue can slow your reflexes, affect your attention, affect your judgment, and cause you to fall asleep at the wheel.

The Dangers of Drowsy Driving

Drowsy driving can cause microsleeps. Microsleep is a short, unintended loss of consciousness characterized by the closing of the eyes, head-snapping, or nodding. At 60 mph a 1-second microsleep means that the car will travel about 88 feet without the driver having any control.

car running off the pavement
A 1-second microsleep is enough to cause a dangerous situation.

Every year across the United States, almost 100,000 crashes are caused by drivers falling asleep at the wheel. Almost half of these involve drivers between 15 and 24 years old.

The only way to stop fatigue is by getting enough sleep.

What are the Early Signs of Drowsy Driving?

Below are some of the most common signs of drowsy driving. If you recognize any of them while driving, try to pull off the road and get some rest before continuing.

  • Missing road signs
  • Slow reactions
  • Tired, sore or heavy eyes
  • Daydreaming
  • Struggling to stay in the lane
  • Troubles changing gear
  • Yawning
  • Poor concentration
  • Drowsiness
  • Blurred vision
  • Dim/fuzzy vision
car driving on Highway and looking in the mirror
If you find yourself having a hard time staying in your lane – pull off the road.

Not sleeping for 17 hours has the same effect on driving as a BAC of 0.05 and not sleeping for 24 hours has the same effect as a BAC of 0.10.

When Does Driver Fatigue Normally Happen?

  • When you drive soon after waking up. You have a high risk of fatigue during the first 30 minutes after waking up.
  • If you’re driving when you would normally be sleeping (e.g. 10 pm – 6 am). Your blood pressure and temperature fall during these hours, which impairs your ability to perform tasks (this is part of your natural sleep pattern and there is nothing you can do about it). Crash risk is much higher during these hours.
  • When you have been awake for longer than usual. The risk increases greatly after being awake for 17 hours.
  • When you haven’t had enough sleep, you can acquire a ‘sleep debt’ that can only be repaid by sleeping.
  • When you have been driving non-stop for a long time. The longer you drive, the higher the risk of fatigue.
You’re at higher risk of becoming fatigued if driving at night.

How to Avoid Drowsy Driving

  • Don’t drive when tired!
  • Drive with a companion – that way you can switch drivers every once in a while.
  • Schedule regular stops (e.g. 15 minutes every 2 hours).
  • Avoid driving just after waking up. Your body won’t have adjusted fully.
  • Don’t take alcohol and/or medications to become more alert. It will have the opposite effect.
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