Transporting Cargo Safely
What this domain tests
The Cargo domain tests whether you can load, distribute, and secure freight so it cannot shift, fall, or overload an axle. Iowa CDL questions focus on tie-down rules, weight limits, inspections, and the consequences of poor securement.
Core rules
- Know the cargo weight and the vehicle’s axle and gross weight ratings before loading; overloaded axles reduce steering and braking control.
- Use at least two tie-downs for articles longer than 10 feet, and add one tie-down for each additional 10 feet of length.
- The aggregate working load limit (WLL) of all tiedowns must be at least 1.5 times the cargo weight for general freight.
- Do not obscure lights, reflectors, plates, or the rear view; cargo must not extend beyond allowed limits without proper flags and permits.
- Recheck securement within the first 50 miles, then every 150 miles or 3 hours, whichever comes first.
Worked example
A 20,000-pound load needs an aggregate WLL of at least 30,000 pounds. If each strap has a 5,000-pound WLL, four straps provide only 20,000 pounds and fail the rule. Six straps provide 30,000 pounds and meet the minimum. The reasoning is simple division: required aggregate WLL divided by WLL per tiedown equals the number needed, before considering placement and angle.
Traps
Counting straps instead of adding WLL; using cut or frayed straps; assuming initial securement stays tight; and forgetting that angled tiedowns can reduce effective capacity. A load that looks stable can shift after the first hard brake.