Dwell time in trucking: what detention means for the driver's clock

Dwell time on this site usually means something happening at a port: a ship at the berth, a container in the terminal yard, or the queue of vessels waiting offshore, all covered in dwell, explained precisely. Trucking has its own dwell clock, and it happens somewhere else entirely: at the shipper's or receiver's loading dock, before the box ever reaches a marine terminal or after it has already left one. The industry usually calls this detention rather than dwell, though drivers and dispatchers use both words loosely. This guide is about that clock, not the three port-side ones.

Road-side dwell: the truck at the dock

Road-side dwell is the time a truck and its driver sit at a shipper's or receiver's facility waiting to be loaded or unloaded. Every stop has some legitimate loading or unloading time built in. Detention is what a shipper or receiver's own facility, not a marine terminal, causes when it keeps the truck past the time the load or unload should reasonably take: a driver who arrives on time and then waits two hours before a dock door opens is the plain case.

Not the same word as the container-side fee

This site also uses "detention" for a different charge entirely: the fee an ocean carrier bills an importer for holding its container off the terminal too long, covered in demurrage, detention and free time. That is a BOX sitting somewhere, with the ocean carrier as the biller. Road-side dwell is a TRUCK sitting somewhere, caused by a private shipper or receiver and billed by the trucking company to its customer. Same word, two different parties, two different clocks, and neither one is a port or terminal metric.

How carriers calculate and bill it

There is no federal detention rate schedule. FMCSA does not set or publish what a shipper or receiver owes a carrier for detention; the threshold and the rate are set commercially, in the contract or rate agreement between the trucking company and its customer. The American Transportation Research Institute, the industry's own research arm, treats time beyond two hours at a facility as the working definition, and reported that in 2023 drivers were detained on 39.3% of stops. Most fleets do charge for it (94.5% in ATRI's 2024 survey), but collection is inconsistent: fewer than half of those invoices get paid.

Hours of service: why the clock keeps running

Detention costs more than the wait itself because of how hours-of-service rules work. A driver's on-duty clock starts when the workday begins and runs continuously through on-duty time that is not driving, including a wait at a dock; it does not pause for detention. A long wait can burn hours off the window a driver has left to drive that day, sometimes before the truck is even loaded, which is why detention shows up in driver pay and carrier scheduling, not just as a delay.

The toll, in the industry's own numbers

This site does not track road-side dwell or detention itself; there is no live public feed for it the way there is for the ship queue or the truck planning-time index charted above. The truck index measures something adjacent but different: how much longer the ROAD trip to and from a port complex takes than free-flow conditions, not how long a truck sits still at a shipper's or receiver's dock once it gets there. Two federal studies have put numbers on the toll of the dock-side wait. A 2018 Department of Transportation Office of Inspector General audit estimated that a 15-minute increase in the time a truck spends at a facility raises the average expected crash rate by 6.2%, and associated detention with $1.1 billion to $1.3 billion in lost annual earnings for for-hire truckload drivers and $250.6 million to $302.9 million in lost annual income for their carriers. ATRI's 2024 update put the industrywide cost of detention in 2023 at $15.1 billion, $11.5 billion in lost productivity and $3.6 billion in direct expenses, with for-hire trucking alone losing more than 135 million hours to it.

The Dwell reports public port-congestion data. It does not track individual trucks, detention charges or driver pay, and this guide is descriptive only, not a rate schedule or a billing-dispute guide. For the port-side clocks this word usually means here, see dwell, explained precisely. For the container-side fee that shares the word "detention," see demurrage, detention and free time.