Examkin

Question

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

A motor carrier operates a three-axle combination vehicle consisting of a two-axle single-drive tractor coupled to a single-axle semitrailer. The vehicle specification records list the following ratings and weights:

- Unladen (tare) weight: 18,600 lbs18,600\text{ lbs}
- Manufacturer Gross Combination Weight Rating (GCWR): 58,000 lbs58,000\text{ lbs}
- Steer axle Gross Axle Weight Rating (GAWR): 12,000 lbs12,000\text{ lbs}
- Drive axle Gross Axle Weight Rating (GAWR): 22,000 lbs22,000\text{ lbs}
- Trailer axle Gross Axle Weight Rating (GAWR): 20,000 lbs20,000\text{ lbs}

Under federal interstate highway regulations, single axles are capped at a statutory limit of 20,000 lbs20,000\text{ lbs}, and total gross combination weight is capped at 80,000 lbs80,000\text{ lbs}. Assuming cargo weight can be distributed across all axles without exceeding any individual rating or statutory limit, what is the maximum legal cargo payload weight (in pounds) that this vehicle combination can transport?

Answer: 33400 lbs

Answer

33,400 lbs
The maximum legal cargo payload is determined by subtracting the tare weight from the most restrictive governing gross weight limit. Each axle is governed by the lesser of its manufacturer GAWR and statutory limit: steer at 12,000 lbs12,000\text{ lbs}, drive capped at 20,000 lbs20,000\text{ lbs}, and trailer at 20,000 lbs20,000\text{ lbs}. The total maximum gross weight supported by the axles is 52,000 lbs52,000\text{ lbs}, which is less than the GCWR (58,000 lbs58,000\text{ lbs}) and federal gross limit (80,000 lbs80,000\text{ lbs}). Subtracting the 18,600 lbs18,600\text{ lbs} tare weight yields an allowable cargo payload of 33,400 lbs33,400\text{ lbs}.

Step-by-Step Solution

1
Determine the governing weight limit for each individual axle.
Steer axle: 12,000 lbs12,000\text{ lbs}; Drive axle: 20,000 lbs20,000\text{ lbs}; Trailer axle: 20,000 lbs20,000\text{ lbs}.
An axle cannot legally exceed either its manufacturer GAWR or the federal statutory limit for single axles (20,000 lbs20,000\text{ lbs}). The drive axle GAWR (22,000 lbs22,000\text{ lbs}) is restricted by the statutory cap of 20,000 lbs20,000\text{ lbs}.
2
Calculate the maximum allowable gross combination weight based on the combined axle limits.
12,000 lbs+20,000 lbs+20,000 lbs=52,000 lbs12,000\text{ lbs} + 20,000\text{ lbs} + 20,000\text{ lbs} = 52,000\text{ lbs}.
The sum of the individual governing axle limits defines the physical axle capacity ceiling for the entire combination.
3
Identify the overall governing gross weight ceiling among axle sum, GCWR, and federal gross maximum.
Maximum legal gross combination weight =52,000 lbs= 52,000\text{ lbs}.
The vehicle combination is constrained by the lowest of the sum of axle limits (52,000 lbs52,000\text{ lbs}), the manufacturer GCWR (58,000 lbs58,000\text{ lbs}), and the federal gross cap (80,000 lbs80,000\text{ lbs}).
4
Calculate maximum allowable cargo payload.
52,000 lbs−18,600 lbs=33,400 lbs52,000\text{ lbs} - 18,600\text{ lbs} = 33,400\text{ lbs}.
Payload is calculated by subtracting unladen tare weight from the governing gross combination weight.

Key Concept

Allowable Cargo Payload and Governing Weight Limits (GAWR vs. GCWR vs. Statutory Caps)
Estimated Time:1m 30s
Rate this question

Topics

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

More questions from this topic