SDDC provides ocean terminal, commercial ocean liner service and traffic management services to deploy, sustain and redeploy U.S. forces on a global basis. The command is responsible for surface transportation and is the interface between DOD shippers and the commercial transportation carrier industry. This includes movement of DOD member household goods and privately owned vehicles. SDDC is the USA's largest customer to the moving industry with more than 500,000 household goods moves a year. The command also provides transportation for troops and materiel (materials) to ports of departure in the U.S. and overseas and provides SPM (Single Port Manager) functions at ports worldwide in support of the surface movement of United States Department of Defense cargo, including military terminals at Sunny Point, North Carolina, and Concord, California.