Development of surfacing criteria for low-volume roads in South Dakota

On a daily basis, local road agencies in South Dakota face the challenge of how to maintain low-volume roads cost-effectively. Specifically, agencies are faced with the decision of determining when it is most economical to maintain, upgrade, or downgrade a road's existing surface. To assist decision makers with maintenance and rehabilitation decisions, the South Dakota Department of Transportation (SDDOT) initiated a study in 2002 to investigate surfacing criteria for low-volume roads. The overall objective of this research is to create a process that allows users to compare the costs associated with different types of roads to provide assistance in deciding which surface type (hot-mix asphalt, blotter, gravel, or stabilized gravel) is most economical under a specific set of circumstances. In addition to incorporating economic factors into the analysis, the process allows the user to consider other noneconomic factors that are more subjective and difficult to quantify. The process used during this study is flexible enough to allow users to consider any combination of agency costs incurred by the agency for maintaining its roads, user cost factors such as vehicle operating costs or crash potential, and noneconomic factors such as politics and housing densities. The methodology was created with agency cost and user cost models developed on the basis of specific road section information supplied by various local agencies in South Dakota, average daily traffic and crash occurrence information supplied by the SDDOT, information obtained through a literature search, and input from members of the project's technical panel.