A five-axle tractor-semitrailer combination is being operated on an interstate highway. Th… — Commercial Driver's License (CDL) General Knowledge Exam

A five-axle tractor-semitrailer combination is being operated on an interstate highway. The power unit has a manufacturer Gross Combination Weight Rating (GCWR) of $86,000\text{ lbs}$ . When crossing a certified public scale, the vehicle records the following axle weights:

- Steer axle: $11,800\text{ lbs}$
- Drive tandem axle group: $35,400\text{ lbs}$
- Trailer tandem axle group: $31,200\text{ lbs}$
- Total Gross Combination Weight (GCW): $78,400\text{ lbs}$

Based on standard federal commercial vehicle weight limits, which of the following statements correctly evaluates the legal operating status of this combination?

A
The vehicle is legally compliant because its total gross combination weight of $78,400\text{ lbs}$ is below the manufacturer Gross Combination Weight Rating of $86,000\text{ lbs}$ .
The vehicle is overloaded because the drive tandem axle group exceeds the federal statutory limit of $34,000\text{ lbs}$ , despite total gross weight being within legal limits.Answer
C
The vehicle is legally compliant because each individual axle in the drive tandem group carries $17,700\text{ lbs}$ , which is below the single-axle statutory limit of $20,000\text{ lbs}$ .
D
The vehicle is overloaded because federal regulations restrict five-axle combination vehicles to a maximum statutory gross weight of $75,000\text{ lbs}$ .

Answer

The vehicle is overloaded because the drive tandem axle group exceeds the federal statutory limit of

34,000\text{ lbs}

, despite total gross weight being within legal limits.

Federal commercial vehicle regulations enforce a maximum allowable weight of

34,000\text{ lbs}

on tandem axle groups and

80,000\text{ lbs}

on total gross combination weight. While the overall gross weight (

78,400\text{ lbs}

) and steer axle (

11,800\text{ lbs}

) comply with federal laws, the drive tandem axle group weighs

35,400\text{ lbs}

, exceeding the federal limit by

1,400\text{ lbs}

. A vehicle is legally overloaded if any axle group exceeds its statutory threshold.

Step-by-Step Solution

Evaluate the total gross combination weight against federal statutory limits and manufacturer ratings.

The vehicle's gross combination weight is

78,400\text{ lbs}

, which is within the federal statutory limit of

80,000\text{ lbs}

and below the manufacturer GCWR of

86,000\text{ lbs}

A commercial motor vehicle must satisfy both overall gross limits and manufacturer structural ratings.

Evaluate each individual axle group against federal statutory limits.

Steer axle:

11,800\text{ lbs} \leq 20,000\text{ lbs}

(legal). Trailer tandem:

31,200\text{ lbs} \leq 34,000\text{ lbs}

(legal). Drive tandem:

35,400\text{ lbs} > 34,000\text{ lbs}

(overloaded by

1,400\text{ lbs}

Federal regulations dictate that tandem axle groups cannot exceed

34,000\text{ lbs}

, regardless of total combination weight.

Determine overall compliance status.

The vehicle is operating illegally due to an overloaded drive tandem axle group.

Exceeding any single statutory limit makes the entire vehicle configuration non-compliant.

Key Concept

Federal statutory weight limits require compliance at both the axle-group level (

20,000\text{ lbs}

single,

34,000\text{ lbs}

tandem) and total gross level (

80,000\text{ lbs}

), and manufacturer ratings (GCWR) cannot override these legal ceilings.

Estimated Time:1m 0s

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