The ease of approach to one location from other locations: in terms of the distance travelled, the cost of travel, or the time taken. The improvement of infrastructures produces an increase in accessibility that positively affects the competitiveness of the economic system and favours the appearance of specialization benefits and scale economies. In fact, regions with high levels of accessibility to the locations of input materials and markets tend to be more productive and competitive than peripheral and remote regions; see Gutiérrez in R. Kitchin and N. Thrift, eds (2009). Accessibility also refers to the ability to connect with information, knowledge, and people.

Topological accessibility

is measured in relation to a system of nodes and paths (transportation network), assuming that accessibility is significant only to specific elements of a transport system, such as airports or ports. Contiguous accessibility is a measurable attribute of every location, as space is considered in a contiguous manner. See Miller and Wu (2000) GeoInformatica 4, 2 on GIS software for space-time accessibility measures. Physical accessibility is the spatial separation of people from the supply of goods and services; see, for example, Orcao and Diez-Cornago (2007) Area 39, 3 on physical access to health services in Spain, and Gage and Calixte (2006) Pop. Studs 60, 3 on maternal health services in Haiti. Social accessibility is the ability of an individual to reach a resource or location, as affected by class structures, income, age, educational background, gender, or race. See Parks (2004) Econ. Geog. 80, 2 on social accessibility in Los Angeles, and the UK Transport Studies Group’s Social Accessibility Mapping Project.