A transport terminal is composed of a set of intermodal infrastructures taking advantage of a geographical location, conferring a higher level of accessibility to local, regional, and global markets. Depending on the mode being considered, terminals are bound to various degrees to their sites. For instance, maritime transportation terminals are particularly dependent on local conditions, especially for large port activities which can be accommodated in a limited number of locations. Airport terminals are more flexible in their locations, but still bound to specific locational constraints. Terminals fulfill three general functions within transport systems:
- Connectivity. Transport terminals provide connectivity within a modal transport network as they are the only locations from which a network can be entered or exited. For instance, subway stations are the connecting nodes of a transit network, while ports and airports are the connecting nodes within maritime and air networks.
- Interface. Transport terminals provide an interface between transport modes enabling passengers and cargo to transit. Ports and airports are points of interface between maritime or air and land transport systems.
- Buffer. Transport terminals provide a buffer between the different capacities and frequency of the transport modes they connect, such as a port for maritime and land transportation systems. A containership carrying thousands of containers may call a port once every two days, while trucks carrying single containers may come in and out of the terminal every few minutes. A similar analogy applies to airports that act as buffers between the various levels of service of land transport systems and the scheduling of air services.