Drayage · July 9, 2026
A heavy container is legal to haul — but only with the right axle setup, route and permit. Here's how it works.
Ocean containers don't care about U.S. road law. A 20-footer packed with something dense — tile, stone, machinery, liquids — can easily put you over legal highway weight once it's on a chassis. Move it wrong and it's a fine, a stuck load, or an unsafe truck. Move it right and it's just another container.
Federal law caps you at 80,000 lbs gross without a permit, with limits per axle (roughly 12,000 on the steers, 34,000 on each tandem). Washington follows those, plus bridge-law spacing rules. The cargo weight might be legal in the box but illegal on the truck if it's on the wrong chassis or the axles aren't spread to carry it.
Go over 80,000 gross or over an axle limit and you're into overweight-permit territory — a state permit, sometimes a specific routing, and often a tri-axle or spread-axle chassis to keep each axle legal. The Ports of Seattle and Tacoma see a lot of heavy freight, so this is routine work, but it has to be set up before the truck shows up, not after.
We flag heavy containers before dispatch, match them to the right chassis (tri-axle or spread where needed), pull the permit and set the route, and make sure the axle weights are legal — not just the gross. Because we run the drayage ourselves, the weight gets checked against the equipment before the truck rolls, not discovered at the scale.
The word "overweight" gets used for two completely different problems and they have different consequences.
Problem one: the box is heavy but legal. Gross weight is above what a standard chassis and axle configuration can carry legally, but within what Washington allows on the right equipment. Nothing dramatic happens at the terminal. What happens is that the wrong truck shows up, discovers the weight at the scale, and either refuses the load or takes a routing that cannot support it. The cost is a wasted move, a lost gate appointment, and a day closer to your Last Free Day. This is the common case, and it is entirely avoidable by knowing the weight before dispatch.
Problem two: the box is over what any legal configuration can carry. Now it genuinely cannot leave as a single road move. The options are a permit where one is available for that weight and route, or stripping cargo out of the container at the port or at a nearby dock until it is legal — a partial transload. Both cost money and both take time, and both are far cheaper decided in advance than discovered at the gate.
What the terminal does and does not do. The terminal is not policing your axle weights on the way out; it hands you the box on the chassis you brought. Enforcement happens on the road, at the scales, and the ticket and the liability are the carrier's and the shipper's, not the terminal's. Which means nobody at the gate will stop you making an expensive mistake.
The one that catches people out: it was legal on the water and is not legal on the road. An ocean container's payload limit and a US road legal gross weight are different constraints. A container can be perfectly within its own rating, loaded correctly at origin, and still be illegal on a standard chassis in Washington. The packer overseas has no reason to know that.
The gross weight from the bill of lading, the container size, the terminal and the delivery address. With those four we can tell you whether it moves on a standard chassis, needs a tri-axle, needs a permit, or needs to be lightened — before a truck is sent and before a gate slot is burned. That conversation takes five minutes. Discovering it at a scale costs a day.
About one in sixteen of the Ad Hoc containers with a recorded gross weight is over 44,000 lbs — routine enough to have a process for, rare enough that the wrong truck still gets sent when nobody checks — see our case studies.
Federally, 80,000 lbs gross without a permit, with axle limits around 12,000 lbs on the steer and 34,000 lbs per tandem. Washington follows these plus bridge-spacing rules. Over any of them and you need an overweight permit.
When the loaded truck exceeds 80,000 lbs gross or any axle limit. That usually also means a tri-axle or spread-axle chassis to keep each axle legal, and sometimes a specified route.
The cargo can be within limits in the box but still overload an axle if it's on the wrong chassis or the axles aren't spread to distribute it. Matching the container to the right chassis is the fix.
Yes — heavy freight is routine at these ports. We match the box to the right chassis, pull the permit and set a legal route before dispatch.
Talk to us about a heavy container →
Usually nothing at the terminal — they hand you the box on the chassis you brought. The problem appears on the road, at a scale, and the cost lands on the carrier and the shipper. The expensive version is a truck that arrives, discovers the weight and cannot take it: a wasted move and a lost gate slot.
Partially, yes — cargo can be removed until the load is legal, either at the port or at a nearby dock. It costs a handling and it is normally the last resort, after the right chassis and a permit have been ruled out.
The gross weight is on the bill of lading. Compare it against a legal road gross weight, not against the container's own payload rating — they are different limits and the second one will reassure you wrongly.
Tell us what you are moving and a dispatcher replies the same day.