CDL Combination Vehicles TestInspecting Combination VehiclesHard
When inspecting the cargo securement in a combination vehicle, you notice that a heavy load of machinery is secured with only two tie-downs over the top. The machinery weighs 20,000 lbs. According to federal regulations, what is the minimum aggregate working load limit (WLL) required for the tie-downs to secure this load against movement in all directions?
- A15,000 lbs
- B20,000 lbs
- C5,000 lbs
- D10,000 lbs
Show answer & explanationAnswer & explanation
Correct answer: D. 10,000 lbs
Federal regulations (FMCSA 393.106) require that the aggregate working load limit (WLL) of all tie-downs used to secure an article of cargo must be at least one-half (50%) of the weight of the article. For a 20,000 lb load, 50% is 10,000 lbs. Additionally, specific rules for heavy machinery require a minimum number of tie-downs based on length, and direct tie-downs are often required, but the aggregate WLL calculation is fundamental.
Why the other options are wrong
- A. 15,000 lbs would be sufficient but is not the minimum required.
- B. 20,000 lbs would mean the WLL equals the cargo weight, which is more than the minimum required 50%.
- C. 5,000 lbs is insufficient; it's only 25% of the load weight.
Cargo Securement WLL Rule
The aggregate working load limit (WLL) of all tie-downs must be at least one-half (50%) of the weight of the cargo being secured.
- WLL is the maximum weight a component can safely hold.
- Applies to securing cargo against movement in all directions.
- Additional rules apply for specific cargo types (e.g., machinery, logs).
Memory trick: Half the weight, safe and sound, that's the WLL you've found!