Improved accessibility modeling and its relation to poverty – A case study in Southern Sri Lanka

Many studies have found close relationships between accessibility and various socio-economic indicators. Yet, since accessibility tends to have differentiated effects, both socially and spatially, there is a need for a model which allows for a disaggregated analysis of accessibility. The model should be possible to use in areas where road network data is incomplete. In this paper such an accessibility model is developed, using a raster-based approach in a Geographical Information System (GIS). One important factor in accessibility modeling is to estimate the traveling speed on different landscape entities. This paper develops a method where local knowledge and physical geographical data are integrated in the GIS model. From the interview data the best door-to-door traveling speeds of three road classes were estimated. The results from these calculations have been used as frictions for a cost surface. The analysis shows strong relationships between poverty indicators and estimated spatial accessibility, stronger than the commonly used accessibility measure of Euclidian distance.

Research highlights
► This research develops a new method to integrate local knowledge and geographical data to model accessibility in a GIS environment in a rural region of Sri Lanka.
► The modeled measure of accessibility is related to the spatial distribution of poverty.
► More generally it proposes methods to overcome poor data availability and quality common in developing countries.
► It was found that poverty on a regional level is not alleviated by market accessibility (important for farmers) but instead poverty decreases with accessibility to towns.