Algorithmic and simulation-based optimisation of blading maintenance of a gravel road network

Abstract

Paper presented at the 23rd Annual Southern African Transport Conference 12 - 15 July 2004 "Getting recognition for the importance of transport", CSIR International Convention Centre, Pretoria, South Africa. Gravel roads are maintained by an activity called blading, which entails the redistribution of surface material over the road surface using a mechanical grader. Blading may be performed dry or wet, depending on the condition of the road surface, and compacting of the graded road may also be required in some cases. The required frequency of blading is a function of the road usage pattern and the properties of its surface material. Emergency blading may be required when a road was damaged by natural phenomena or an abnormal usage pattern. The Provincial Government of the Western Cape (PGWC) is supporting research aimed at the optimization of blading activities on its gravel road network. To start off an investigation was undertaken to determine the constraints and variables that would determine the domain within which optimised routes for blading teams might be determined. Based on the results of this investigation, two possible solution techniques were devised and a third possibility identified through a literature study. The constraints and variables of the particular problem are described as well as the possible solution techniques. The merits of simulation-based optimisation are compared to those of directly solved algorithmic optimisation.