In some cases the networks are provided by a single mode, but more often transport is provided by a series of interconnected networks; the road network can be combined with the air transport network to offer door-to-door service. In some instance the networks are combined and provided by a single operator, but in others independent actors offer interactive networks of services. There are important links between transportation networks and the spatial economy. The form and technology of a transportation network affects location and production decisions. Networks issues can be considered in several ways. The discussion in this chapter largely concerns networks involving interconnectivity. Connectivity occurs when there is a connection between two points. Interconnectivity involves at least three nodes. For it to be worthwhile to develop a network of any configuration rather than simply provide single-link services there must exist some form of network economy. These economics may be on the cost side but they may also reflect the possibility of earning higher revenues on the demand side. On the cost side there may simply be traditional economies of scale linked to having larger operations and the ability to spread fixed costs over a larger number of customers but there may also be additional network benefits associated with particular network configurations.
Abstract