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How does driver fatigue contribute to car accidents?


How does driver fatigue contribute to car accidents?

Driver fatigue affects people from all walks of life, from those who commute for work to those who drive for a living. Long hours behind the wheel can cause drowsiness and a reduction in focus for any driver, no matter their age or health.

The National Safety Council notes that more than 300,000 crashes occur annually due to drowsy driving. While the circumstances behind these crashes may vary, the physical and mental fatigue connected with drowsy driving often causes the same dangerous symptoms for those behind the wheel.

Delayed reaction time

Drivers who operate a motor vehicle while sleepy or fatigued tend to experience a reduction in reflexes that may cause an accident. Awareness of their surroundings may fall and lead to several different crash risks, including:

  • Striking stopped traffic
  • Hesitation at intersections
  • Braking too soon or too late

The risk of such accidents tends to increase depending on how sleep-deprived drivers become.

Vision changes

Drowsiness can affect driver vision, especially in desolate areas where the landscape does not change for miles. When drowsiness occurs, drivers may find it difficult to focus their vision on the road, may drift into other lanes or experience dry or gritty eyes that could interfere with clear vision.


Some drivers with extreme fatigue may experience micro-naps, where sleep occurs without drivers knowing it. These periods of semi-consciousness usually last no longer than five or six seconds, but a crash can happen in half that time when drivers micro-sleep behind the wheel.

Drivers can avoid accidents connected with drowsiness by increasing how much sleep they get a night and by creating a consistent and healthy sleep schedule.