An operator is preparing a commercial motor vehicle for a route through an area experienci… — Commercial Driver's License (CDL) General Knowledge Exam

An operator is preparing a commercial motor vehicle for a route through an area experiencing heavy snow, slush, and sub-freezing temperatures. To ensure equipment reliability and maintain vehicle stability, which combination of pre-trip inspection standards and driving procedures must the driver follow?

A
Engage the engine retarder at its highest setting to assist service brakes on slick downgrades, and maintain a standard 4-second following interval.
Verify steer tires have at least $\frac{4}{32}\text{ inch}$ of tread depth, disengage engine retarders on slick pavements, and lightly apply brakes before parking to dry wet linings and prevent freeze-up.Answer
C
Accept a minimum tread depth of $\frac{2}{32}\text{ inch}$ on steer tires, and bleed air from drive tires below manufacturer pressure ratings to widen the contact patch for traction.
D
Rely on spare electrical fuses as the only required emergency warning item, and add only 1 additional second of following distance when operating on hard-packed snow.

Answer

Verify steer tires have at least

\frac{4}{32}\text{ inch}

of tread depth, disengage engine retarders on slick pavements, and lightly apply brakes before parking to dry wet linings and prevent freeze-up.

The correct safety standard requires verifying that steer tires maintain at least

\frac{4}{32}\text{ inch}

of tread depth, deactivating engine retarders on slick pavements to avoid drive-wheel skids, and lightly dragging brakes before parking in sub-freezing temperatures to dry out moisture and prevent brake shoe freeze-up.

Step-by-Step Solution

Evaluate pre-trip tire tread depth requirements for winter conditions.

Steer tires must have at least

\frac{4}{32}\text{ inch}

of tread depth in every major groove; all other tires require at least

\frac{2}{32}\text{ inch}

Adequate tread depth on front steer tires is vital to steer through snow and channel slush away from the contact patch.

Assess auxiliary braking rules on slippery road surfaces.

Engine retarders and exhaust brakes must be switched off whenever operating on wet, icy, or snow-covered roads.

Retarder braking force is applied exclusively to the drive axle, which can easily break traction and initiate a sudden drive-wheel skid or jackknife.

Determine the proper procedure for managing brake moisture in sub-freezing weather.

Lightly apply service brakes while driving slowly before coming to a complete stop or parking.

Friction heats and dries the brake linings and drums, preventing moisture from freezing them together overnight.

Key Concept

Winter vehicle inspection standards, retarder deactivation on slippery surfaces, and wet brake freeze prevention.

Estimated Time:2m 0s

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Topics

More questions from this topic