This indicator is measured as the proportion of rural people in the project area who live within 2 kilometers (typically equivalent to a 20-minute walk) of an all-season road. This indicator is also known as Rural Access Index (RAI).
Number of rural people with access to an all-season road
The TTL should indicate also the absolute number of rural people with access to an all-season road, i.e. the numerator of the share, as supplemental data. Note: From the indicator and this supplemental information, the size of the rural population (i.e. the denominator of the share) can be calculated as well. If the shares get aggregated across several project areas, or several countries, the size of the rural population serves as the weight. The supplemental information also allows one to aggregate the absolute number of rural people with access to an all-season road.
Guidance on rural population
"Rural" should follow the definition officially used in the country.
Guidance on all-season road
An all-season road is a road that is motorable all year by the prevailing means of rural transport (often a pick-up or a truck which does not have four-wheel-drive). Predictable interruptions of short duration during inclement weather (e.g. heavy rainfall) are acceptable, particularly on low volume roads.
Guidance on living within 2 kilometers
There are three main approaches to measure this indicator:
- Using mapping geo-referenced population to determine how many people live within 2 kilometers of the classified road network. Limitations relate to assumptions on the passability of the classified network as well as the absence of a non-classified network. The level of confidence is rated as good.
- Extrapolating based on sampling: physical data on population and road length (kilometer) generated in formal surveys are used to extrapolate the index. The level of confidence is rated as fair.
- Using partial spatial estimation: the index is physically measured in a sample of rural areas through geo-referencing of all roads and villages. Limitations come from possible lack of robustness of the sampling process. The level of confidence is rated as fair.