The Marine Transportation System (MTS) consists of waterways, ports, terminals, and intermodal landside connections that allow the movement of people and goods to, from, and on the water. As part of the MTS, the Nation’s ports provide critical connections between waterways, highways, pipelines, and railroads.
U.S.-International Freight Flows by Mode and Weight or Value
Waterborne vessels are the leading transportation mode for U.S.-international trade in goods, moving 41 percent of U.S.-international trade value in 2021—almost $1.9 trillion and nearly 1.6 billion short tons (69 percent of the total weight). In the 1st half of 2022, vessels continued to transport the majority of U.S.-international freight, moving more than $1.1 trillion (43 percent), two-thirds of which was containerized. The following figure shows the total (all), containerized, or noncontainerized monthly U.S.-international freight value transported by vessel.
For every dollar of trade goods exported by vessel from the United States, nearly two dollars are imported by vessel to the United States. Most consumer goods imported into the United States are relatively high value, lightweight, and transported as containerized cargo. Containerized cargo is cargo that will fit into an intermodal shipping container; container vessels provide economies of scale and have been one of the primary
focal points of port performance in recent years. Dry bulk (e.g., grains, coal) and liquid bulk (e.g., chemicals, petroleum, liquefied petroleum gas, liquefied natural gas) are relatively low value and heavy-weight, accounting for the majority of exported tonnage.