What is detention in trucking and drayage?

Detention means two related things depending on who says it. To a drayage operator it is equipment detention: the ocean carrier charging by the day for its container, and often its chassis, while they sit outside the terminal past free time. Many carriers bill this as per diem, and the two words are used interchangeably. To a truck driver it is driver detention: hours spent waiting at a dock to be loaded or unloaded, past the free time in the rate confirmation.

Same idea, different asset. One is the carrier renting you its box, the other is the trucker renting you its driver's day.

For containers, the terminal gate is the line. While the loaded box sits inside the terminal the charge is demurrage. The moment it gates out, the equipment clock starts, and it runs until the empty is received back. That window is longer than most back offices assume, and it depends heavily on the port.

In live drayage data the average time a container spends outside the gate ranges from about three days at the fastest terminals to more than two weeks at the most congested ones. Same container, same carrier, very different detention exposure.

On the road, the standard deal is two hours free at the dock, then an hourly rate. The waiting is not rare. ATRI's 2024 study of 2023 data found detention on 39.3% of stops, costing the industry about $3.6 billion in direct expenses and another $11.5 billion in lost productivity. Nearly every fleet, 94.5%, charges for it, but fewer than half of those detention invoices actually get paid.

The rate itself is modest. An OOIDA survey of drivers found owner-operators collecting around $53 an hour on average and company drivers closer to $37, well under the roughly $80 an hour drivers said would be fair. And it is not only money. The DOT Inspector General found that every extra 15 minutes of average dwell raised the expected crash rate by 6.2%, because the hours lost at the dock get made up on the highway.

Detention is one of the few charges where the carrier is owed money and still does not bill it. The reason is paperwork, not generosity. The proof of the wait lives in one system, the driver's GPS or ELD arrival and departure times. The invoice lives in another, the TMS. Somebody has to match the two, stop by stop, and attach the evidence before the customer will pay.

That matching is tedious enough that it quietly stops happening. One drayage operator was spending about three hours a day of a staffer's time lining up GPS timestamps against container records by hand. Most carriers never get that far, and the detention they earned becomes a discount they never meant to give.

For equipment detention and demurrage, the Federal Maritime Commission's billing rule took effect on May 28, 2024. Ocean carriers and terminals now have 30 days from the last day a charge accrued to send the invoice, and the invoice has to show the container, the dates, how the amount was calculated, and a point of contact. Miss the deadline or leave out a required element, and the billed party does not have to pay. The billed party also gets at least 30 days to dispute.

One part did not survive. In September 2025 a federal appeals court struck down the provision limiting who could be billed, so a trucker with its own contract with the ocean carrier can be invoiced directly again. The 30-day clock and the invoice requirements still stand. Separately, the FMC has said since 2020 that charging detention when an empty cannot be returned is likely unreasonable, which matters every time a depot turns a driver away.

Collecting detention is a data problem with a deadline. For driver detention it means capturing arrival and departure automatically and attaching them to the load before invoicing. For equipment detention it means tracking every empty to its return receipt and checking every carrier invoice against the 30-day rule and your own timestamps.

When both happen without a person stitching systems together, detention goes back to what it was meant to be: a charge that gets billed when it is earned and disputed when it is not.