Examkin

Question

Difficulty: MediumWinter Driving, Snow, and Black Ice

You are driving on a highway at night in sub-freezing temperatures around 28∘F28^\circ\text{F} (−2∘C-2^\circ\text{C}). The road surface ahead looks dark and wet, but you notice that the tires of the vehicle traveling ahead of you are no longer throwing up any water spray. What condition does this visual cue most likely indicate?

  1. The surface moisture has frozen into transparent black ice, creating extremely slippery driving conditions.Answer
  2. B
    The road surface has completely dried, indicating that it is safe to travel at the posted speed limit.
  3. C
    The vehicle ahead is hydroplaning, requiring you to immediately slam on your brakes to prevent a collision.
  4. D
    The vehicle ahead is entering a rear-wheel skid, so you should steer sharply in the opposite direction of the rear slide.

Answer

The sudden disappearance of water spray from tires on a dark, wet-looking road in freezing temperatures indicates that surface water has frozen into black ice.
On cold days when temperatures are near or below freezing (32∘F32^\circ\text{F} / 0∘C0^\circ\text{C}), a road that appears wet but produces no tire spray from preceeding vehicles indicates that the moisture has frozen into a smooth layer of black ice. Recognizing this warning sign allows drivers to ease off the accelerator early and avoid sudden maneuvers.

Step-by-Step Solution

1
Analyze ambient environmental factors and visual roadway cues.
The ambient temperature is below freezing (28∘F28^\circ\text{F} / −2∘C-2^\circ\text{C}) and the pavement appears dark and shiny.
Freezing temperatures turn standing liquid water into invisible ice sheets.
2
Evaluate the behavior of leading traffic tire spray.
Liquid water creates visible spray when lifted by spinning tires; solid ice produces no spray.
The absence of tire spray on a wet-looking road surface confirms that surface moisture has solidified into black ice.
3
Determine the appropriate safe driving response under basic speed laws.
Smoothly reduce speed, increase following distance, and avoid abrupt steering or braking inputs.
Black ice drastically reduces tire friction, requiring defensive speed adjustments well below posted limits.

Key Concept

Visual Detection of Black Ice via Tire Spray Observations
Estimated Time:1m 0s
Rate this question

Topics

Winter Driving, Snow, and Black Ice

More questions from this topic