Accessibility, network efficiency, and transport infrastructure planning

Most accessibility measures reported in the literature do not meet certain requirements of transport planners, as the results offered by these indicators are heavily influenced by the geographic location of the places. Peripheral locations invariably figure as being of low accessibility and consequently as possible receptors for new investments, even though they may already have a very good provision of transport infrastructure. In this paper an accessibility indicator is formulated that neutralizes the effect of geographic location. To this end, the customary notion of distance (length, time, or costs) is substituted by another which expresses the ease of access in terms of network efficiency. This indicator can be useful to assist decisions to invest in transport networks, as it is more sensitive than the potential model to the transport infrastructure needs of each individual region. It has been tested by application to the current Spanish Infrastructure Master Plan.