Short sea shipping has the potential to reduce the amount of oil consumed by heavy trucks by shifting ton-miles onto ships and waterborne highways that travel up and down our coasts and interior waterways. In addition, waterborne goods movement generally faces fewer failure points: while trucks face traffic, failing bridges, and potential for accidents, ships can largely circumvent these barriers to affordable, on-time delivery. Currently, short sea shipping is hampered by a costly harbor maintenance tax on all shipped goods and infrastructure limitations at key ports. Port improvements and further government support of "marine highways" in specific transportation corridors will help lower short sea shipping costs and convince shippers that sending goods by boat is just as safe and reliable as sending them by truck.
Bureau of Transportation Statistics. 2007. National Transporation Statistics, table 1-46b, “U.S. Ton-Miles of Freight.” Washington DC: U.S. Bureau of Transportation Statistics. link