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Difficulty: Very hardWeight Definitions and Limits (GVWR, GCWR, Axle Weights)

A commercial driver is operating a 3-axle straight delivery truck towing a 2-axle pup trailer. To ensure legal compliance before transit, the driver reviews the manufacturer specification plates and current scale weights.

Manufacturer Ratings:
- Truck Gross Vehicle Weight Rating (GVWR): 52,000 lbs52,000\text{ lbs}
- Truck Gross Combination Weight Rating (GCWR): 72,000 lbs72,000\text{ lbs}
- Trailer Gross Vehicle Weight Rating (GVWR): 26,000 lbs26,000\text{ lbs}

Current Scale Weights (measured while fully coupled on a platform scale):
- Truck steer axle: 11,000 lbs11,000\text{ lbs}
- Truck drive tandem axles: 19,000 lbs19,000\text{ lbs}
- Trailer tandem axles: 25,000 lbs25,000\text{ lbs}

The trailer is sealed and will not receive any additional cargo. The driver needs to load heavy machinery into the truck's cargo box. Assuming perfect weight distribution over the truck's axles and sufficient individual tire ratings, what is the absolute maximum payload weight the driver can legally load onto the truck without violating any manufacturer ratings or standard federal interstate weight limits?

  1. 17,000 lbs17,000\text{ lbs}Answer
  2. B
    22,000 lbs22,000\text{ lbs}
  3. C
    24,000 lbs24,000\text{ lbs}
  4. D
    25,000 lbs25,000\text{ lbs}

Answer

17,000 lbs17,000\text{ lbs}
The maximum legal payload is strictly determined by the most restrictive bottleneck among all federal limits and manufacturer ratings. Evaluating all constraints: the truck's GCWR restricts the entire combination to 72,000 lbs72,000\text{ lbs}. Since the combination currently weighs 55,000 lbs55,000\text{ lbs} (30,00030,000 truck + 25,00025,000 trailer), a maximum of only 17,000 lbs17,000\text{ lbs} can be added safely (72,000−55,000=17,00072,000 - 55,000 = 17,000). Although the truck's GVWR (52,000 lbs52,000\text{ lbs}) technically has 22,000 lbs22,000\text{ lbs} of remaining capacity, and federal axle limits allow up to 24,000 lbs24,000\text{ lbs}, the GCWR creates the lowest, binding limit.

Step-by-Step Solution

1
Calculate the current weight of the truck and the entire combination based on the scale readings.
Current Truck Weight = 30,000 lbs30,000\text{ lbs} (11,00011,000 steer + 19,00019,000 drive). Total Combination Weight = 55,000 lbs55,000\text{ lbs} (30,00030,000 truck + 25,00025,000 trailer).
Establishing current weights is the prerequisite for calculating available capacity against legal and manufacturer limits.
2
Determine the available payload capacity based strictly on the truck's Gross Vehicle Weight Rating (GVWR).
Truck GVWR (52,000 lbs52,000\text{ lbs}) - Current Truck Weight (30,000 lbs30,000\text{ lbs}) = 22,000 lbs22,000\text{ lbs} available.
The truck power unit cannot legally exceed its manufacturer-designated structural weight limit.
3
Determine the available payload capacity based on standard federal statutory axle and gross weight limits.
Federal Gross: 80,000−55,000=25,000 lbs80,000 - 55,000 = 25,000\text{ lbs} available. Federal Axles: Steer allowance (20,000−11,000=9,00020,000 - 11,000 = 9,000) + Drive Tandem allowance (34,000−19,000=15,00034,000 - 19,000 = 15,000) = 24,000 lbs24,000\text{ lbs} available.
Federal law strictly caps interstate gross weight at 80,000 lbs80,000\text{ lbs}, single axles at 20,000 lbs20,000\text{ lbs}, and tandem axles at 34,000 lbs34,000\text{ lbs}.
4
Determine the available payload capacity based on the manufacturer's Gross Combination Weight Rating (GCWR) and identify the binding bottleneck.
GCWR (72,000 lbs72,000\text{ lbs}) - Total Combination Weight (55,000 lbs55,000\text{ lbs}) = 17,000 lbs17,000\text{ lbs} available.
The absolute maximum legal payload is dictated by the lowest (most restrictive) limit among all calculated constraints (17,000 lbs17,000\text{ lbs} is lower than 22,00022,000, 24,00024,000, and 25,00025,000).

Key Concept

To determine maximum allowable payload, operators must calculate available capacity across all structural ratings (GVWR, GCWR) and statutory regulations (federal gross, axle limits). The lowest resulting value represents the legally binding maximum limit.
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Topics

Weight Definitions and Limits (GVWR, GCWR, Axle Weights)

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