The Rural Access Index (RAI) is a measure of access, developed by the World Bank in 2006. It is now the key rural access indicator for the UN Sustainable Development Goals (SDGs) and has been incorporated as SDG 9.1.1. This measures the proportion of the rural population living within 2 km of an all-season road, using GIS layers and relying on three data sources: population, road network location and condition.There is potential to use open source GIS data for population and road location, but the most challenging aspect of the RAI is to define the all-season status of the road network.
The World Bank defines the term all-season as ‘a road that is motorable all year round by the prevailing means of rural transport, allowing for occasional interruptions of short duration’. Every country measures its road condition in a different way and against different parameters, for example some countries use visual assessment, some use speed and some use road roughness. Similarly countries use different levels of condition, typically between three and five levels, for example Good, Fair and Poor. This makes finding consistency for the assessment of an all-season road between countries very challenging.
The UKAid funded programme Research for Community Access Partnership (ReCAP) has commissioned research to refine the methodology for assessing SDG 9.1.1 to make it more sustainable, repeatable and consistent by using geospatial data and tools. This is an important aspect of refining the RAI and has been trialled in four countries, Ghana, Malawi, Myanmar and Nepal; selected for their diversity of environment and data. Where existing condition data exists, paved roads have been considered as ‘all-season’ if they are in Good or Fair condition, whereas unpaved roads would need to be in Good condition to be considered as all-season. Whilst this provides an initial coarse estimate of all-season access, it ignores a number of important issues with rural road networks, where for example poor condition paved roads and fair condition unpaved roads could provide all-season access, which could significantly affect the measurement of RAI.
TRL have developed a method of using ‘Accessibility Factors’ to determine the allseason status of road networks, using GIS tools. These factors are applied to the population and network location layers and substitute the need to measure the road condition, which can be an onerous and expensive process for low income countries.