Examkin

Question

Difficulty: MediumHot Weather Driving

On a sunny afternoon with high ambient temperatures, a truck driver observes shiny black patches developing along the wheel paths of an asphalt road. What hazard do these patches present, and what is the correct driving action?

  1. The patches are bleeding tar, which creates a very slippery road surface and requires reducing speed to maintain vehicle control.Answer
  2. B
    The patches indicate softened asphalt that creates excessive drag, requiring continuous application of engine retarders to stabilize road speed.
  3. C
    The patches represent severe structural pavement failure that triggers steer tire blowouts, requiring immediate hard service braking.
  4. D
    The patches indicate localized oil residue, which only poses a skidding risk if the steer tires have less than 4/32 inch of tread depth.

Answer

The patches indicate bleeding tar from the road pavement, creating a very slick surface that requires slowing down to maintain control.
Under high ambient and surface temperatures, tar in asphalt pavement rises and bleeds to the surface. This produces very slick patches that reduce tire grip, requiring the driver to slow down to prevent skids and maintain safe control.

Step-by-Step Solution

1
Identify the environmental road condition described in the scenario.
Recognize that intense solar heat draws tar up from asphalt pavement, forming shiny patches known as bleeding tar.
Extreme heat softens asphalt binders and causes them to rise to the pavement surface.
2
Determine the impact of bleeding tar on vehicle dynamics.
Understand that bleeding tar significantly reduces tire-to-road friction and creates extremely slippery driving conditions.
The liquid-like tar layer prevents tire treads from effectively gripping the aggregate in the roadway.
3
Select the correct CDL safe driving protocol for slippery road conditions.
Reduce vehicle speed and increase following distance to prevent skidding and maintain adequate stopping margins.
Adjusting speed downwards compensates for reduced traction and prevents drive-wheel slide or jackknife.

Key Concept

Tar Bleeding and Traction Loss in Hot Weather
Estimated Time:1m 0s
Rate this question

Topics

Hot Weather Driving

More questions from this topic