Question

Difficulty: HardDriving in Adverse Weather and Low Visibility

You are traveling on a rural two-lane highway with a posted speed limit of 55 mph when a sudden severe rainstorm drops visibility to under 150 feet and creates standing water in the wheel ruts. Other traffic has slowed to approximately 30 mph. Under the Basic Speed Law and standard low-visibility driving rules, which of the following actions is legally required and safest?

  1. A
    Maintain the posted speed limit of 55 mph since it is the legally designated maximum for the highway, while switching on your high-beam headlights to improve visibility.
  2. Reduce your vehicle speed to a rate that is safe for the reduced visibility, maintain low-beam headlights, and increase your following distance behind preceding vehicles.Answer
  3. C
    Slow to 30 mph but switch on your high-beam headlights to penetrate the rain and signal your presence to oncoming traffic.
  4. D
    Maintain 55 mph to prevent being rear-ended by trailing traffic while repeatedly applying firm pressure to the brakes to clear water from the tires.

Answer

The driver must reduce speed below the posted limit to a rate safe for visibility, utilize low-beam headlights to prevent glare, and expand following distance.
The correct response recognizes that under the Basic Speed Law, drivers must adjust their speed downward when rain, fog, or poor visibility creates hazardous conditions. Using low-beam headlights prevents glare caused by light reflecting off precipitation, and increasing following distance provides essential reaction time on wet pavement.

Step-by-Step Solution

1
Evaluate environmental hazards and visibility limits
Standing water increases hydroplaning risk, and visibility under 150 feet restricts stopping sight distance.
Safe stopping distance must never exceed sight distance.
2
Apply the Basic Speed Law
The posted 55 mph limit is no longer legal or safe; speed must be reduced to match road and visibility conditions.
Traffic laws dictate driving at a speed reasonable and prudent for existing hazards regardless of posted limits.
3
Select correct vehicle equipment controls
Activate low-beam headlights and wipers while increasing following interval.
Low beams illuminate the road ahead without reflecting glare back from atmospheric water droplets.

Key Concept

Basic Speed Law compliance and headlight management in severe rain and low visibility
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