THE GEOGRAPHY OF TRANSPORT SYSTEMS


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Transportation / Land Use Relationships

Transportation and economic systems have a reciprocal relationship. In other words, transport supply and demand are mutually interdependent. For instance, the construction of an highway interchange favors the concentration of commercial and service activities, which will generate additional transport demand, which in turn will favor the location of new activities and a reorganization of the regional spatial structure. This interdependence can be conceptualized with three major elements:

  • Transport system. Is mainly composed of infrastructures conferring a level of supply, from which can be derived levels of accessibility as well as transportation networks. For instance, traffic assignment models take an existing spatial interaction structure and infer flows within a transportation network. Conceptual flows consequently become a physical reality.
  • Spatial interactions. Assume flows between locations mainly through a function of spatial impendence, which reflect the friction of the urban space. They have a long tradition in geography and many spatial interaction models were developed. They rely on distance decay parameters as well as the modes involved in urban trips.
  • Land use. Represents a level of spatial accumulation from which transport demand is derived. There is a wide base of spatial economic models aiming at estimating transport demand, mainly through the generation and attraction of traffic by different land use zones.