TruckDisp Equipment Specifications Flashcards

A flatbed trailer is rated at 48,000 lbs payload capacity, but the shipper wants to load 47,200 lbs of steel coils. The tractor's front axle weighs 11,800 lbs unloaded and the rear tandem axle weighs 34,600 lbs unloaded. What is the primary compliance concern before accepting this load?

Answer: The combined gross vehicle weight will exceed the 80,000 lb federal limit

Total GVW = 11,800 + 34,600 + 47,200 = 93,600 lbs, which far exceeds the 80,000 lb federal gross vehicle weight limit. Even though the payload is under the trailer's rated capacity, trailer capacity ratings do not override federal GVW limits. The dispatcher must reject or restructure the load.

A refrigerated trailer (reefer) unit specs show a temperature range of -20°F to +70°F with a 'continuous run' fuel consumption of 0.8 gal/hr at 0°F ambient. A load of frozen seafood must travel 1,400 miles estimated at 56 hours transit time. The trailer's fuel tank holds 50 gallons. What is the MINIMUM number of fuel stops required for the reefer unit alone?

Answer: At least 1 stop — fuel consumption will likely exceed tank capacity

At 0.8 gal/hr over 56 hours, the reefer consumes 44.8 gallons. However, 0.8 gal/hr is specified at 0°F ambient. Real-world variation (door openings, defrost cycles, temperature swings) typically increases consumption by 10–25%, potentially pushing total consumption to 50–56 gallons — exceeding the 50-gallon tank. The correct answer acknowledges this operational reality. A dispatcher must plan for at least one precautionary fuel stop.

A carrier operates a 53-ft dry van with a kingpin-to-rear-axle (KPRA) distance of 41 feet. The shipper loads the heaviest pallets at the rear of the trailer, resulting in a rear tandem axle weight of 36,500 lbs. The bridge formula for a 41-ft spread calculates the maximum allowable weight as 35,870 lbs. What is the dispatcher's correct course of action?

Answer: Instruct the driver to slide the rear tandems forward to reduce the KPRA and increase the bridge formula allowance

Sliding the rear tandem axles forward shortens the KPRA distance. A shorter KPRA produces a lower bridge formula allowance for weight, but the key issue here is that the load weight (36,500 lbs) exceeds the bridge formula maximum (35,870 lbs) for the current 41-ft spread. Sliding tandems rearward increases the axle spread, which increases the bridge formula allowance — the correct directive. Sliding forward would worsen the violation. Simply approving it ignores bridge law. The 34,000 lb per-axle limit applies per individual axle, not the tandem group.

A step-deck trailer has a main deck height of 48 inches and a lower deck height of 22 inches. A piece of machinery is 11 feet 2 inches tall and must be loaded on the lower deck. The tractor's fifth wheel height is 52 inches. What is the approximate total loaded height, and is a permit required?

Answer: Approximately 13 ft 8 in; an overheight permit is required in most states

The lower deck of a step-deck sits at 22 inches (1 ft 10 in) from the ground. Adding the cargo height of 11 ft 2 in gives 11 ft 2 in + 1 ft 10 in = 13 ft 0 in at the load top. However, the fifth wheel height (52 in = 4 ft 4 in) creates a slight nose-up pitch on the trailer that effectively raises the rear deck — industry standard adds approximately 6–8 inches for this pitch effect on step-decks loaded at the rear. Total estimated height: ~13 ft 6–8 in, which triggers overheight permit requirements (legal max is 13 ft 6 in in most states). A dispatcher must order a permit.

A liquid tanker is certified for a maximum of 9,500 gallons of product. The product being loaded is ethanol with a specific gravity of 0.789. The tanker's maximum payload rating is 45,000 lbs. How many gallons can legally be loaded before the weight limit — not the volume limit — becomes the binding constraint?

Answer: Approximately 6,832 gallons, after which the 45,000 lb payload limit is reached

Water weighs 8.34 lbs/gal. Ethanol's specific gravity of 0.789 means it weighs 8.34 × 0.789 = 6.58 lbs/gal. Dividing the 45,000 lb payload limit by 6.58 lbs/gal = approximately 6,838 gallons. At that point, the weight limit is hit well before reaching the 9,500-gallon volume capacity. A dispatcher must calculate product density — not just volume — to determine the actual load limit.

A flatbed carrier has a trailer with 4-inch ratchet straps rated at 5,400 lbs Working Load Limit (WLL) each. The load is 42,000 lbs of unsecured steel pipe (round cross-section). Per FMCSA cargo securement rules for this load type, what is the MINIMUM number of tie-downs required?

Answer: At least 14 tie-downs — FMCSA requires aggregate WLL ≥ 50% of load weight for round pipe, and additional placement rules apply

FMCSA regulations (49 CFR 393.116) for steel pipe require aggregate WLL of tie-downs to equal at least 50% of cargo weight: 42,000 × 0.50 = 21,000 lbs. At 5,400 lbs WLL each, that's at minimum 4 tie-downs for weight alone. However, steel pipe (cylindrical) in multiple tiers requires chocking or cradling AND tie-downs at each point of contact to prevent rolling, with spacing rules (one every 10 ft for loads over 5 ft). For a typical 40-ft load of pipe, placement rules mandate far more tie-downs than the weight formula alone — commonly 14 or more. Answer A ignores the 50% rule; answer C overstates the requirement; answer D undercounts placement-driven requirements.