Examkin

Question

Difficulty: MediumRetarders Usage and Cautions

While hauling freight on an interstate, a driver encounters sudden freezing drizzle that turns the pavement slick. Which of the following describes the correct procedure for managing the vehicle's retarder system under these conditions?

  1. Switch off the retarder completely to prevent the drive wheels from losing traction and causing a skid.Answer
  2. B
    Increase the retarder setting to maximum to minimize friction heat on the primary service brakes.
  3. C
    Keep the retarder active only while navigating downhill curves to maintain steer-axle tracking.
  4. D
    Leave the retarder in automatic mode to allow the anti-lock braking system to regulate drive-wheel drag.

Answer

Turn off the retarder completely to prevent the drive wheels from losing traction and causing a skid.
On slick, wet, icy, or snow-covered roads, retarders must be switched off because the supplemental braking force applied to the drive wheels can cause them to lose traction and trigger a serious drive-wheel skid.

Step-by-Step Solution

1
Identify the environmental condition and vehicle component involved.
The roadway is covered with freezing drizzle (slick/low traction), and the vehicle is equipped with an auxiliary retarder.
Retarder safety rules strictly depend on road surface friction.
2
Evaluate the mechanical operation of retarders on drive axles.
Retarders apply supplemental braking torque directly to the drive wheels whenever the throttle is released.
When traction is compromised, even moderate auxiliary braking torque can break drive-tire adhesion.
3
Determine the required driver safety action.
The driver must switch the retarder system to the OFF position.
Disabling the retarder prevents inadvertent wheel lockup and avoids triggering a drive-wheel skid or jackknife.

Key Concept

Disengaging retarders on slippery or low-traction road surfaces to prevent drive-wheel skids
Estimated Time:1m 0s
Rate this question

Topics

Retarders Usage and Cautions

More questions from this topic