What is Driver Fatigue?
Driver fatigue is a state of mental or physical exhaustion that reduces alertness, slows reaction time, and impairs judgment behind the wheel. It is a leading cause of road accidents and can occur even when a driver feels only mildly tired.
Driver fatigue is exhaustion that reduces alertness and reaction time, leading to slower decision-making and increased crash risk. A fatigued driver is as impaired as a moderately intoxicated one.
Step-by-step worked examples
You have been driving for 4 hours without a break. What happens to your alertness and reaction time?
After 4 hours, alertness drops to approximately 60–65%. Reaction time increases by 20–30% (e.g., 1.5 s → 1.8–2 s). Decision-making ability declines; peripheral vision narrows. Crash risk increases 4–5 times compared to well-rested driving.
You feel your head nodding and eyelids drooping at 80 km/h on a highway. What is the safest response?
STOP immediately at the next safe location (service station, rest area). Never try to 'push through' fatigue—brain becomes uncontrollable. 20 min nap or 2 hours rest is minimum recovery. If alone, call for alternative transport; do not continue driving.
You are scheduled for an 8-hour drive tomorrow. How many stops should you plan?
Plan stops every 2 hours maximum. For 8 hours: 4 planned stops, each 15–30 minutes long. Include one longer break (1–2 hours) halfway through. Ensure sleep before the drive: 7–8 hours minimum; fatigue compounds.
Flashcards
Quick quiz
Q1.A driver has been on the road for 5 hours without stopping. Alertness is approximately:
Q2.Nodding off at the wheel is:
Q3.The most reliable way to combat driver fatigue is:
Q4.You feel drowsy after driving 3 hours. Legal options include:
The full card deck, worked steps and AI-tutor support for “What is Driver Fatigue?” are in Notek — study by hand before your exam.
Common mistakes
Fatigue is just mild sleepiness—you can push through with concentration. — Correct: Fatigue impairs judgment as much as alcohol; pushing through increases crash risk exponentially.
Drinking coffee will solve fatigue; you can then drive safely for hours. — Correct: Caffeine works in 20–30 minutes and provides only temporary relief. Naps are the true fix.
Talking on the phone or listening to music prevents fatigue. — Correct: Stimulation masks symptoms but doesn't restore mental alertness. Crash risk remains high.
Nodding off for 2–3 seconds is safe if traffic is light. — Correct: Micro-sleep at 100 km/h means 55 m of uncontrolled travel—a crash is nearly inevitable.
FAQ
What is driver fatigue?
Exhaustion that reduces alertness, slows reaction time, and impairs decision-making. It is as risky as moderate alcohol impairment.
What are the warning signs of fatigue?
Yawning, heavy eyelids, head nodding, difficulty maintaining lane position, and difficulty recalling recent driving.
How often should drivers take breaks?
Every 2 hours maximum; 15–30 min stops to stretch, drink water, and rest eyes. Longer breaks (1–2 hrs) improve recovery.
Is caffeine an effective fatigue treatment?
Caffeine provides temporary relief (20–30 min delay) but is unreliable for long drives. Naps and proper sleep are more effective.