A number of studies have acknowledged the positive impacts that rural roads have
on the social and economic development of a region. This impact is due to the
increased accessibility offered by road development. The effect of the social impact,
however, has proven to be difficult to quantify, with many studies opting to use
ratings to define this impact. The need to quantify the social impact arises from the
need to aid decision-making processes, which seek to identify or prioritise the most
cost effective projects. This is more often the case in rural communities where a
typical economic prioritisation method, such as a cost-benefit analysis, will likely
yield unfavourable results because of the low traffic volumes present on these roads.
The method proposed for prioritisation in this research introduces an accessibility
index that takes into account the accessibility provided by the road infrastructure,
and by transportation modes, and by public facilities such as public schools and
clinics. The data required to formulate and validate the model was collected in three
villages located in the Limpopo Province of South Africa. The accessibility provided
by the road infrastructure is quantified as the percentage of the length of the road
link that conforms to road classification standards. The standards relate to travel
speed for motorised transport and cross sectional dimensions for non-motorised
transport. The probabilities of a preference to use a facility or transport mode are
used as accessibility indices for the facilities and the transport modes. The
probabilities are a result of stated preference experiments, which take into account
the different quality attributes of public facilities, and characteristics of the transport
mode. The final weighted accessibility index is obtained by considering the number
of users in each observed facility in South Africa and the budget allocated to it. This
enables the accessibility index to be converted further into a monetary value that is
compared with the cost of successfully completing the project and the figures that
arise from alternative projects. The facilities investigated were selected with the
guidance of the National Development Plan (NDP) and included public schools and
public healthcare facilities.
The exercise resulted in accessibility indices that were used successfully to rank
seven hypothetical projects from two of the identified villages. The research showed
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that, for low-volume roads, non-motorised transport modes are just as important as
motorised transport modes. Other key findings were made which illustrated
significant variables that influence preference for transport modes, school
attendance and clinic visitation.