Over time, the use of oceanborne containers to transport international trade has affected the distribution of total maritime trade among U.S. ports. In the 1980s, when U.S.-Asia-Pacific Rim trade was modest, east coast ports handled the majority of U.S.-international maritime trade. As trade with Asia grew, the east coast ports’ share of the value of trade declined while west coast ports’ share increased reflecting the growth in container traffic between the two regions. Also during this period, changes in industrial activity in the Midwest affected the volume and type of cargo moving through Great Lakes ports. During this period, several industrial changes, such as changes in the location and distribution of final assembly plants and companies that produce auto parts, affected manufacturing activities in the Midwest. Since the 1990s, some auto companies and parts producers have moved out of the Midwest, impacting overall goods movements in the Great Lakes region. Gulf of Mexico ports experienced a modest increase in their relative share as trade with Latin America grew.
Over half, nearly 55 percent, of U.S. containerized merchandise trade in terms of TEUs passed through west coast ports in 2005, up from 42 percent in 1980. Regionally, west coast ports grew the fastest during this 25-year period (figure 3).
Although west coast ports handled the most container trade, they also had a larger share of the oceanborne containerized trade deficit, in terms of the export-import balance, than other regional U.S. ports. Overall, west coast ports serve more as U.S. import gateways than as export gateways to the rest of the world. In contrast, east coast ports tend to handle more container exports than imports. Gulf coast ports handle nearly an equal share of container imports and exports.
Container trade also affects the pattern of freight movement within the United States. Nearly all U.S. oceanborne container trade is transported by rail carriers, long-haul truck carriers, or local truck carriers to and from origins and destinations throughout the country. The growth in U.S.-international merchandise trade, particularly U.S. containerized trade, is placing pressure on the nation’s transportation network and influences traffic congestion in the areas surrounding the major U.S.-international gateways.