Examkin

Question

Difficulty: HardDriving in Fog

When navigating a commercial vehicle through dense fog that has deposited moisture on the roadway, engaging the auxiliary engine retarder at its highest setting is recommended to assist in decelerating within the reduced sight distance without overheating the service brakes.

Answer: Answer

Answer

The statement is false.
The statement is false because moisture condensation from fog creates slick pavement conditions. Auxiliary engine retarders apply non-service braking torque directly to drive axles; when applied on slippery roads, they can easily cause drive wheels to lock and induce a violent jackknife or drive-wheel skid. Safe commercial driving procedures dictate disabling retarders on wet or slick surfaces.

Step-by-Step Solution

1
Assess the roadway surface condition resulting from fog accumulation.
Fog creates condensation and a greasy, slick moisture film across the pavement surface, significantly reducing tire traction.
Identifying reduced pavement friction is necessary to select appropriate deceleration mechanisms.
2
Analyze the mechanical operating dynamics of auxiliary engine retarders on reduced-traction surfaces.
Engine retarders apply substantial mechanical braking force exclusively to the drive axle wheels.
Concentrated braking torque on drive wheels without trailer brake activation can initiate wheel slip on low-friction pavement.
3
Apply standard commercial motor vehicle safety guidelines for retarder operation in adverse weather.
Commercial drivers must disengage auxiliary retarders on wet, icy, or fog-slicked roads to eliminate the risk of an unrecoverable jackknife or skid.
Maintaining directional stability and drive-wheel traction takes precedence over brake temperature management.

Key Concept

Disengaging auxiliary engine retarders on moisture-slicked pavement during fog operations to prevent drive-wheel skids.
Estimated Time:1m 0s
Rate this question

Topics

Driving in Fog

More questions from this topic