Marine Highways

Innovations: US/MARAD Marine Highways

West Coast Corridor

The M-5 Corridor

US Maritime Administration

Coastal shipping, short sea shipping and America’s Marine Highway are all terms that describe waterborne freight that is transported without crossing a major ocean or leaving a continent. According to the U.S. Maritime Administration (MARAD), coastal shipping reduces the infrastructure constraints of clogged highways, which in turn curtails the need for expensive bridge retrofits, road expansion and additional highway safety funding.

The European Union’s (EU) Marco Polo Program funds coastal shipping through its Motorways of the Sea grant program. The entire intermodal program, which includes rail, aims to remove the equivalent of 700,000 trucks per year between Paris and Berlin, or 74.4 billion tons of freight per mile, which in turn will reduce congestion and emissions, while improving throughput and reliability.

In the United States, coastal shipping is not very popular. Though the mode has been around for some time, only 2% of U.S. freight moves via domestic water. Shipping routes between the Pacific Northwest and Alaska, as well as routes along the Eastern seaboard, have long been used to transport goods; however, coastal shipping is generally secondary to trucking, which is seen as more flexible and without as many legal and financial constraints. There are also environmental concerns, including fuel type and the potential need to expand port operations to accommodate coastal shipping. The two U.S. cases highlighted here, SeaBridge Freight and the 64 Express, are exceptions, and have demonstrated considerable benefits, including reduced congestion along high-traffic truck corridors.

Funding from the National Defense Authorization Act for Fiscal Year 2010 (HR 2647) provides language for short sea shipping infrastructure and freight transportation needs within the United States, though money has yet to be allocated.

Sponsor: West Coast Corridor Coalition

Supporters: Pacific Northwest Waterways Association, California Marine Affairs and Navigation Conference,
Humboldt Bay Harbor, Recreation, and Conservation District / Port of Humboldt Bay, Port of Skagit County,
WA, Skagit County Board of Commissioners, Town of La Conner, WA, and Swinomish Tribal Community.

Landside Corridor Served: Interstate-5

Corridor Description:

The M-5 Corridor includes the Pacific Ocean coastal waters, connecting commercial navigation channels,
ports, and harbors from San Diego, CA to the US-Canada border north of Seattle, WA. It spans Washington,
Oregon and California along the West Coast. It connects to the M-84 Corridor at Astoria, OR, and the M-580
Connector at Oakland, CA.


This corridor contains several areas identified by the U.S. Department of Transportation as having considerable annual truck hours of delay, most notably in the urban areas of California, Portland, OR, and Seattle, WA. The Department reports that Southern California and the Pacific Northwest are also plagued with freight rail congestion. Total domestic trade movements between the three States along the I-5 Corridor are expected to grow from 145 million tons per year to 366 million tons by 2030, exacerbating existing challenges.

Navigable coastal waters that parallel the entire I-5 Corridor, combined with numerous deep and safe rivers, bays, and ports, can help to accommodate some of this expected increase in traffic, reducing landside travel delays and greenhouse gas emissions along this essential freight corridor.