Development of a Simplified Agency Life-Cycle Costing Tool for Gravel Roads

Abstract

Understanding how roads behave is necessary both for their design and also to make sure that suitable and appropriate maintenance is programmed and carried out effectively. The problem is that this is not an easy task because there are many variables that affect road performance, and these differ from place to place. This is true of both paved and unpaved roads. Most countries have a large network of rural unpaved roads that require regular maintenance at relatively high total cost over many years. If the performance of such roads can be improved, especially in whole life terms, their costs can be reduced. Decision support tools such as the highway development and management system have been developed based on several studies in different countries. The performance models developed as a result of these studies often contain many variables and require extensive data collection before they can be used. This is often beyond the resources available. To improve this situation and to develop better understanding of the performance of gravel roads, this study was undertaken in six countries. It was found that two material characteristics, namely plasticity product and grading modulus, had a major effect on the performance of gravel roads, and were found to predict the performance of gravel roads to an acceptable level of accuracy. The results of the study were used to develop a simple life-cycle costing model for gravel roads that allows engineers to improve the performance of gravel roads and to reduce whole life costs.

Rural Transportation Infrastructure in Low- and Middle-Income Countries: A Review of Impacts, Implications, and Interventions

“…In an attempt to extend the benefits that rural transportation infrastructure can bring to communities [7][8][9]207], particular experts have honed their focus onto pieces of the rural transportation system that serve different functions [208]. Rural roads are a widely discussed strategy that may also be referred to as feeder roads, tertiary roads, low-volume rural roads (LVRRs), community-level roads, village-roads, and lower class roads [34,38,[209][210][211][212][213]. Despite varied interpretations of rural roads across different contexts [214], characteristics such as a limited traffic volume [214,215], low travel speeds [216], limited levels of engineering [such as sealing and drainage] [2,216], and a focus on first [or last] mile mobility challenges appear routinely [217].…”

“…Strategically implementing rural roads in LMICs is a challenging endeavor. Typically relying on limited engineering, basic materials, and being constructed without prior technical appraisal, rural roads often require substantial maintenance that can be difficult to effectively deliver in environments with limited resources and institutional organization [211,215,222,226,228]. Further, road construction in many LMICs is often driven by political connotation and lacks formalized strategy, which limits the positive impacts that may be cultivated for rural dwellers [221].…”

“…Both recent reviews and further evidence suggest that maintenance [and similarly described activities such as rehabilitation] can be a highly cost effective intervention with reported rates of return on investment of up to 40%, compared to a rate of 10% more commonly achieved through the creation of new infrastructure [7][8][9]207]. However, rural infrastructure authorities in LMICs often lack the necessary resources, organization, and strategy to properly maintain roads, leading to rapid degradation that both increases costs over time and counteracts benefits for rural people [4,22,211,247,249]. Accordingly, the literature has presented strategies to organize, institutionalize, and incentivize rural transportation maintenance works by advocating for increased data collection and management [58,60,249,250], improved funding arrangements [215,246], and increased participatory and community engagement [7,228,251].…”