The lessons learned from conducting a condition survey on unsealed roads surfaced with marginal materials in the Iringa region, Tanzania

Abstract

The data from the road condition survey has a number of applications, some of these are to determine optimal grading and reshaping frequencies. However, due to the number of variables contributing to the performance of gravel roads, each road organization has to record the characteristics of the distress on the gravel roads in their locality. This is due to the fact that variables behind distress formulation are not readily transferable from one geographical location to the other. This is the case, particularly if the locations in question differ in climatic condition, gravel material characteristics, quality of construction and maintenance, terrain, traffic characteristics and driver behaviours. This paper has focused on the condition survey done on gravel roads in the Iringa region. The survey was part of the research to establish a gravel loss prediction model ideal for local application. The results of the condition survey came out with, among other things, a new range of grading coefficient to suit the local marginal materials used for surfacing gravel roads in the Iringa region.