How do ocean carriers organize the empty containers reposition activity in the USA?

The routing of empty containers is an unavoidable activity of the intermodal chain. In fact, import containers that arrive at a national port are sent toward a multiplicity of interior destinations. Then the empty containers must return to a port to accomplish an export voyage. The purpose of this paper is to analyse the organizational choice of ocean carriers to reposition their empty containers in the USA. Ocean carriers have four options to relocate their empty containers: the spot organization and the adoption of three different renewable contracts to frame the externalization. How do ocean carriers choose their organization form to relocate their empty containers?