Fatigue slows down the central nervous system, increasing the time it takes to perceive a hazard, process the information, and execute a physical response, such as braking.
What effect does being awake for 18 hours have on driving ability?
Being awake for 18 consecutive hours can cause impairment equivalent to having a blood alcohol concentration (BAC) of 0.05%.
How does being awake for 24 hours compare to being legally drunk?
Being awake for 24 hours can cause impairment equivalent to having a BAC of 0.10%, which is higher than the legal limit for alcohol in all U.S. states.
How does fatigue affect a driver's judgment and decision-making?
It impairs the ability to make sound, safe decisions. A fatigued driver is more likely to take risks, such as speeding, tailgating, or making unsafe lane changes.
In what way does drowsiness impact a driver's vision and awareness?
Fatigue can cause blurred vision, reduced peripheral awareness (tunnel vision), and a decreased ability to scan the environment for potential hazards.
What is meant by 'impaired vigilance' in a fatigued driver?
Vigilance is the ability to maintain attention over a long period. Fatigue reduces this ability, making drivers less observant of their surroundings, road signs, and other vehicles.
Can an experienced driver overcome the effects of fatigue through skill alone?
No. The effects of fatigue are physiological and involuntary. No amount of driving experience can overcome the body's biological need for sleep.
How does fatigue impact a driver's ability to handle complex or unexpected situations?
It reduces cognitive flexibility and problem-solving skills, making it much harder to react appropriately to sudden events like a stopped car or a pedestrian.
Why is drowsy driving sometimes called the 'invisible' cause of crashes?
Unlike alcohol, there is no simple test (like a breathalyzer) to determine a driver's level of fatigue after a crash, making it difficult to track and often underreported.
How does fatigue affect a driver's motor skills beyond just reaction time?
It can lead to less precise steering inputs, overcorrection, and a general lack of coordination, all of which are critical for maintaining control of a vehicle.
