A transport hub (also transport interchange) is a place where passengers and cargo are exchanged between vehicles or between transport modes. Public transport hubs include train stations, rapid transit stations, bus stops, tram stop, airports and ferry slips. Freight hubs include classification yards, airports, seaports and truck terminals, or combinations of these. For private transport, the parking lot functions as a hub.
Historically, an interchange service in the scheduled passenger air transport industry involved a "through plane" flight operated by two or more airlines where a single aircraft was used with the individual airlines operating it with their own flight crews on their respective portions of a direct, no change of plane multi-stop flight. In the U.S., a number of air carriers including Alaska Airlines, American Airlines, Braniff International Airways, Continental Airlines, Delta Air Lines, Eastern Airlines, National Airlines (1934-1980), Pan Am, Trans World Airlines (TWA), United Airlines and Western Airlines previously operated such cooperative "through plane" interchange flights on both domestic and/or international services in the past with these schedules appearing in their respective system timetables.
Delta Air Lines pioneered the hub and spoke system for aviation in 1955 from its hub in Atlanta, Georgia, United States, in an effort to compete with Eastern Air Lines. FedEx adopted the hub and spoke model for overnight package delivery during the 1970s. When the United States airline industry was deregulated in 1978, Delta's hub and spoke paradigm was annexed by several airlines. A large number of airlines around the world operate hub and spoke systems facilitating passenger connections between their respective flights.
Intermodal passenger transport hubs in public transport include bus stations, railway stations and metro stations, while a major transport hub, often multimodal (bus and rail), may be referred to as a transport center or, in American English or Canadian English, as a transit center. Sections of city streets that are devoted to functioning as transit hubs are referred to as transit malls.
Modern electronic passenger information systems and journey planners require a digital representation of the stops and transportation hubs including their topology. Public transport data information standards such as Transmodel and IFOPT have been developed to provide a common terminology, conceptual models and data exchange formats to allow the collection and distribution of stop and interchange data.
Airports have a twofold hub function. First they concentrate passenger traffic into one place for onward transportation. This makes it important for airports to be connected to the surrounding transport infrastructure, including roads, bus services, and railway and rapid transit systems. Secondly some airports function as intra-modular hubs for the airlines, or airline hubs. This is a common strategy among network airlines who fly only from limited number of airports and usually will make their customers change planes at one of their hubs if they want to get between two cities the airline doesn't fly directly between.
Airlines have extended the hub-and-spoke model in various ways. One method is to create additional hubs on a regional basis, and to create major routes between the hubs. This reduces the need to travel long distances between nodes that are close together. Another method is to use focus cities to implement point-to-point service for high traffic routes, bypassing the hub entirely.
There are usually three kinds of freight hubs: sea-road, sea-rail and road-rail, though they can also be sea-road-rail. With the growth of containerization, intermodal freight transport has become more efficient, often making multiple legs cheaper than through services--increasing the use of hubs.