The Dwell US port congestion, weekly

Reference

Glossary

The terms the brief uses, defined the way the import trade says them.

Vessel dwell at berth
How long a container ship sits at the berth, from its arrival at the berth to its departure, derived from AIS ship-position data. This is a ship metric. It is the dwell the BTS container-vessel-dwell data measures, and it is not how long a container sits in the yard. This site labels it as vessel dwell every time.
Container dwell (box dwell)
How long a loaded import container sits on the marine terminal after it is discharged, before it leaves by truck or rail. This is a box metric, and it is the one that drives an importer's free-time and demurrage exposure. It is a different number from vessel dwell. This site reports it only where a source publishes it, and says so.
Ships awaiting berth
The count of container ships waiting offshore, at anchor or in a slow-steaming queue, for a berth to open at a port complex. This is a queue, not a dwell time at all. It is published for LA/Long Beach and NY/NJ through MARAD and the Marine Exchange.
TEU (Twenty-foot Equivalent Unit)
The standard container count. A forty-foot box is 2 TEU. Port volumes are quoted in TEU. The monthly statistics split loaded imports, loaded exports and empties; for a US importer the loaded-imports line is the demand read.
Loaded imports, loaded exports, empties
The three TEU streams a port authority reports each month. Loaded imports are inbound full boxes, the import-demand signal. Loaded exports are outbound full boxes. Empties are repositioned empty containers, a tell about trade imbalance and equipment availability.
Import-friction read
This site's composite: a rules-based, descriptive label per port complex, derived from where its component metrics sit against their own trailing-12-month normal. It describes current friction, it never predicts it. The exact rule is on the methodology page.
Trailing-12-month normal
The baseline this site compares a reading against for the friction read and the on-page normal line: the median and range of that series over the prior twelve months. A reading well above its trailing-12-month normal is elevated; well below is eased. The AIS-derived port series are young, so a trailing-12-month band is the honest recent normal.
Demurrage
The storage fee a marine terminal charges for a loaded container left on the terminal past its free time. Rising vessel dwell and a longer ship queue are early warnings that boxes will sit and demurrage exposure will rise. This site reports the congestion, never a fee amount or how to fight one.
Detention
The fee a carrier charges for keeping the carrier's equipment, the container or chassis, too long off the terminal. Detention is the equipment clock, demurrage is the terminal clock. The two are charged by different parties for different things.
Free time and the last free day (LFD)
The days a terminal or carrier allows a container to sit before charges start, and the final day before that clock begins. Free time varies by terminal and contract. This site's calculator counts the days as mechanics, never as fee or negotiation advice.
PTI (Truck Planning-Time Index)
The FHWA truck planning-time index at a port complex: how much longer a drayage trip takes relative to a free-flow baseline. It measures road congestion around the terminals, a proxy for drayage conditions. It is not the terminal turn time, and this site headlines it as a road-congestion proxy, not a turn-time figure.
Truck turn time
The gate-to-gate minutes a drayage truck actually spends inside the marine terminal to drop or pick up a container. It is the number the harbor trucking trade watches most, and it is distinct from the FHWA planning-time index, which measures the road congestion around the complex. HTA and PMSA publish turn times as monthly write-ups rather than a clean public data feed, so this site does not carry them and uses the planning-time index as the public, consistent proxy.
Rail terminal dwell
How long a container waits for its outbound train at an intermodal rail terminal, published by the Surface Transportation Board. It is context for the inland leg of the chain.
Berth
The spot at the wharf where a ship ties up to be worked. A ship awaiting berth is waiting for one to open. Vessel dwell is measured from arrival at the berth to departure from it.
Drayage
The short-haul trucking of a container between the marine terminal and a nearby warehouse or rail yard. The truck planning-time index is a drayage-window signal.
San Pedro Bay
The bay that holds the adjacent ports of Los Angeles and Long Beach, the largest container gateway in the United States. This site groups the two as the LA/Long Beach complex.