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

A commercial driver is operating a 5-axle tractor-semitrailer combination on an interstate highway. The vehicle's data plates and shipping papers indicate the following specifications:

Tractor Manufacturer Ratings:
* Steer Axle GAWR: 12,500 lbs12,500\text{ lbs}
* Drive Tandem Axle GAWR: 38,000 lbs38,000\text{ lbs}
* Tractor GVWR: 50,500 lbs50,500\text{ lbs}
* Tractor GCWR: 80,000 lbs80,000\text{ lbs}

Trailer Manufacturer Ratings:
* Trailer Tandem Axle GAWR: 40,000 lbs40,000\text{ lbs}
* Trailer GVWR: 65,000 lbs65,000\text{ lbs}

Upon crossing a weigh station, the official scale ticket shows:
* Steer Axle: 11,400 lbs11,400\text{ lbs}
* Drive Tandem Axles: 35,600 lbs35,600\text{ lbs}
* Trailer Tandem Axles: 32,000 lbs32,000\text{ lbs}
* Total Gross Weight: 79,000 lbs79,000\text{ lbs}

Based on standard federal weight limits and the manufacturer ratings provided, which of the following best describes the legal and safety compliance of this combination?

  1. The configuration is in violation because the drive tandem axle weight of 35,600 lbs35,600\text{ lbs} exceeds the federal maximum limit of 34,000 lbs34,000\text{ lbs}, despite being under the manufacturer's axle rating.Answer
  2. B
    The configuration is fully compliant because the 35,600 lbs35,600\text{ lbs} drive tandem weight is safely below the manufacturer's 38,000 lbs38,000\text{ lbs} rating, and the total gross weight is under 80,000 lbs80,000\text{ lbs}.
  3. C
    The configuration is in violation because the total gross weight of 79,000 lbs79,000\text{ lbs} severely exceeds the tractor's single-unit Gross Vehicle Weight Rating (GVWR) of 50,500 lbs50,500\text{ lbs}.
  4. D
    The configuration is fully compliant because the total gross weight is less than the combined Gross Vehicle Weight Ratings of both the tractor and trailer (115,500 lbs115,500\text{ lbs}).

Answer

The configuration is in violation because the drive tandem axle weight exceeds the federal maximum limit of 34,000 pounds, despite being under the manufacturer's axle rating.
The vehicle is operating illegally because the drive tandem axles weigh 35,600 pounds, which exceeds the federal interstate maximum of 34,000 pounds for a tandem axle group. The fact that the manufacturer's Gross Axle Weight Rating (GAWR) is 38,000 pounds merely means the axle can physically handle the weight without breaking; however, the lower federal legal limit strictly supersedes the manufacturer's structural rating.

Step-by-Step Solution

1
Evaluate total gross weight against legal and manufacturer limits.
The total weight (79,000 lbs79,000\text{ lbs}) is under both the federal gross limit (80,000 lbs80,000\text{ lbs}) and the tractor's GCWR (80,000 lbs80,000\text{ lbs}).
Gross weight must never exceed the lowest of the federal maximum or the manufacturer's specified GCWR.
2
Evaluate the steer axle weight.
The steer axle (11,400 lbs11,400\text{ lbs}) is under the manufacturer's GAWR (12,500 lbs12,500\text{ lbs}) and the standard single-axle limit (20,000 lbs20,000\text{ lbs}).
Individual axles must be within both legal limits and structural ratings.
3
Evaluate the drive tandem axle weight.
The drive tandem (35,600 lbs35,600\text{ lbs}) is under the GAWR (38,000 lbs38,000\text{ lbs}) but EXCEEDS the federal tandem limit (34,000 lbs34,000\text{ lbs}).
Even if an axle is physically rated by the manufacturer for more weight, it cannot legally exceed the federal interstate limit.
4
Evaluate the tractor's GVWR.
The tractor's actual power-unit weight (11,400 lbs+35,600 lbs=47,000 lbs11,400\text{ lbs} + 35,600\text{ lbs} = 47,000\text{ lbs}) is under its GVWR (50,500 lbs50,500\text{ lbs}).
GVWR strictly applies to the single unit (the tractor), not the entire combination. The total combination is governed by GCWR.

Key Concept

When evaluating commercial vehicle weights, the legal weight limit is always the lower of the manufacturer's rating (GAWR/GVWR/GCWR) or the federal highway limit (20,000 lbs single / 34,000 lbs tandem / 80,000 lbs gross).
Estimated Time:2m 30s
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Topics

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

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