How to build a truck load that is cost-effective and secure

The rules and research behind a full, legal, stable load that arrives with its seal intact.

A good load does two jobs. It carries as much as it legally can, so you send fewer trucks. And it arrives the way it left: nothing shifted, nothing warm, nothing missing. Here is what the rules and the research say about both, for palletized food in 53-foot dry vans and reefers.

Part 1: the most cost-effective load

Fill the truck, but know which limit you hit

You're paying to ship air. Every empty pallet spot rides the whole route and costs the same driver hours and fuel as a full one. But "full" has three meanings: floor spots, cube and weight. For dense freight like produce and drinks, weight usually runs out before space does.

On the Interstate, federal law caps a truck at 80,000 pounds gross, 20,000 pounds on a single axle and 34,000 pounds on a tandem axle pair. A formula called the bridge formula can set a lower gross limit depending on axle spacing, and states set their own limits on other roads.

So a heavy load is not just "under 80,000." Where the pallets sit decides how that weight lands on each axle group. Spread heavy freight along the trailer so no axle group goes over its limit, instead of piling it all at the nose or the doors.

Load in reverse stop order

On a multi-stop route, the last stop loads first, at the nose. The first stop loads last, at the doors. That way no store's pallets are blocked by a later store's. Research on multi-drop loading adds a point many docks miss: each stop takes weight off, so the load must stay stable and balanced on every leg of the route, not only when it leaves the dock.

For reefers, leave room for the air

A cold trailer only works if cold air reaches every pallet. Studies of refrigerated containers found the pallets nearest the doors get the least airflow and run warmest, and an open gap down the center lets cold air rush back to the unit without cooling the product. Those studies were on shipping containers, which blow air differently from a road trailer, so treat them as a guide: block open gaps and watch the door-end pallets.

The federal Sanitary Transportation rule also applies to food that needs temperature control for safety. The shipper must give the carrier the operating temperature in writing, including pre-cooling if needed. The carrier pre-cools the trailer as told. The loader checks that each refrigerated compartment is ready and pre-cooled before loading. Mixed loads need protection too: raw foods and nonfood items must be kept from contaminating other food, by keeping them apart, isolating them or packaging them.

Part 2: the most secure load

Securement: nothing shifts

FMCSA's cargo rules (49 CFR 393, the 393.100 to 136 sections) say cargo must be contained, immobilized or secured so it cannot shift in a way that hurts the truck's stability. The securement has to hold against strong forces: 0.8 g forward, as in a hard stop, and 0.5 g backward and sideways.

In a closed van with strong walls, pallets that touch each other and the walls can meet the rule without straps. The trouble is gaps: a short load, a space at the doors, or the hole a stop leaves behind. The rule names the fixes: load bars, dunnage bags (airbags), blocking, or tiedowns. If you use straps, their combined working load limit must be at least half the weight of the cargo.

• Pack tight. Pallets against each other and the walls are the first line of securement.
• Bar every gap. A load bar or airbag behind the last row, and again after each stop.
• Re-check at stops. The driver closes the gap before driving on.

Security: nothing goes missing

The strongest published playbook for trailer seals comes from U.S. Customs' CTPAT program. It is required only for its members on cross-border freight, but it is a good model for any distributor.

• Use high-security seals. CTPAT calls for seals that meet ISO 17712 (qualifying bolt or cable seals) on loaded trailers.
• Keep a seal log. Count seals when they arrive, store them locked up, log each one you issue, and have a manager check the log against shipping papers.
• Seal with a witness. A trained person applies the seal and a second person watches.
• Check every seal the same way. CTPAT's four-step check: View, Verify, Twist, Tug.

Putting it together

The cheapest load and the safest load are mostly the same load: full to the limit that binds first, heavy freight balanced over the axles, stops in reverse order, gaps barred, cold air flowing, and a seal that is logged and checked. Dock to Route builds loads against floor spots, cube, weight and temperature together, prints the nose-to-doors order for your dock, and records seal checks at the gate, with an alert you can turn on when a seal is broken or does not match the last check.

Sources

• FHWA, bridge formula weights and size and weight FAQ
• Calik and others, routing with cargo stability and multi-drop constraints (KU Leuven)
• 49 CFR 393 subpart I, protection against shifting and falling cargo
• 21 CFR 1.908, sanitary transportation of food
• Nkwocha and others, airflow in refrigerated containers (Acta Horticulturae, 2022)
• CBP, CTPAT seal security procedures job aid