NSC Defensive Driving 4 — Questions and Answers
Question 1: Which factor most commonly contributes to hydroplaning?
- Driving on warm asphalt
- Driving too fast on wet roads with worn tires (Correct answer)
- Using all-season tires in rain
- Having tires inflated above recommended PSI
Correct answer: Driving too fast on wet roads with worn tires
Hydroplaning occurs when water builds up under tires faster than it can be displaced, and worn tires or excess speed worsen this effect.
Question 2: What is the 'two-second rule' designed to measure?
- Time between checking mirrors
- Minimum following distance expressed in time (Correct answer)
- Reaction time after seeing a hazard
- Time allowed to clear an intersection
Correct answer: Minimum following distance expressed in time
The two-second rule ensures a minimum safe following distance expressed as time rather than feet, which adjusts automatically for speed.
Question 3: When driving at night, you should dim your high beams when oncoming traffic is within how many feet?
- 200 feet
- 500 feet (Correct answer)
- 1,000 feet
- 100 feet
Correct answer: 500 feet
NSC guidelines recommend dimming high beams when within 500 feet of an oncoming vehicle to prevent blinding the other driver.
Question 4: What is 'inattentional blindness' in the context of defensive driving?
- Legally blind drivers who obtain restricted licenses
- Failing to see an object in plain sight because attention is focused elsewhere (Correct answer)
- Temporary vision loss from bright headlights
- Difficulty seeing in low-light conditions
Correct answer: Failing to see an object in plain sight because attention is focused elsewhere
Inattentional blindness means the brain misses visible hazards when cognitive attention is diverted, as with phone use.
Question 5: A vehicle behind you is tailgating. What is the safest defensive response?
- Tap your brakes to warn them
- Gradually slow down to increase your own following distance ahead (Correct answer)
- Maintain your speed and ignore them
- Speed up to create more space
Correct answer: Gradually slow down to increase your own following distance ahead
Increasing your following distance to the car ahead gives you a larger buffer so any sudden stop won't result in a three-car crash.
Question 6: What is the effect of carbon monoxide (CO) on a driver's ability to operate a vehicle safely?
- It improves night vision
- It impairs judgment and reaction time, similar to alcohol (Correct answer)
- It only causes fatigue after hours of exposure
- It has no effect at low concentration levels
Correct answer: It impairs judgment and reaction time, similar to alcohol
Even low CO levels reduce oxygen to the brain, impairing judgment, reaction time, and causing drowsiness.
Question 7: What percentage of all traffic fatalities does the NSC attribute to human error?
- 50%
- 75%
- 94% (Correct answer)
- 60%
Correct answer: 94%
NSC research consistently attributes approximately 94% of serious crashes to human error rather than vehicle failure or road conditions.
NSC Defensive Driving 4
Which factor most commonly contributes to hydroplaning?