Maintenance Impact on Economic Evaluation of Upgrading Unsealed Roads

Abstract

The demand for upgrades to unsealed roads is high because road users prefer the comfort and dependability of paved roads; therefore, road agencies are faced with the challenge of upgrading as many kilometers as possible within limited budgets and requirements that govern the economic evaluation of road upgrades. The conditions of unsealed roads vary greatly as a function of the maintenance activities executed over time, but these are typically not applied systematically and thus compromise the transitability of unsealed roads. An argument made against the upgrading of roads with low traffic is typically that proper maintenance funds are not available; therefore, it is best to have a paved road in which the road condition is less susceptible to the maintenance standard applied. This paper presents a methodology for the economic evaluation of whether unsealed roads should be upgraded that was performed with the Highway Development and Management Model by consideration of different assumptions about the maintenance standard applied with or without the upgrade and some sample results. The study shows that the results of the economic evaluation vary according to the assumptions made about the maintenance standard applied. Nevertheless, under a worst- or best-case maintenance standard scenario, one obtains from the evaluation (a) the best investment for a given traffic level and (b) the minimum traffic needed to justify an investment economically. The results presented in the paper should be considered no more than a first approximation of country-specific results. To obtain country-specific results, the methodology should be replicated and adapted with refined country data.