Source: Notteboom, T. and J-P Rodrigue (2005) "Port Regionalization: Towards a New Phase in Port Development", Maritime Policy and Management, Vol. 32, No. 3, pp. 297-313. Notteboom, T. and J-P Rodrigue (2010) "Foreland-Based Regionalization: Integrating Intermediate Hubs with Port Hinterlands", Research in Transportation Economics, Vol. 27, pp. 19-29.
- The first extension (Phase 5; late 1980s - early 1990s) encompasses the explicit integration of transshipment hubs. They tend to have greater depth since they were built recently in view to accommodate modern containership drafts, placing them at a technical advantage. Increasing volumes as such can lead to an increasing segmentation in liner service networks and a hierarchy in hubs (both 'offshore' and 'mainland').
- The second extension (Phase 6; from the late 1990s) relates to the incorporation of inland freight distribution centers and terminals as active nodes in shaping load center development. The port regionalization phase is characterized by strong functional interdependency and even joint development of a specific load center and (selected) multimodal logistics platforms in its hinterland, ultimately leading to the formation of a regional load center network.