In light of financial pressures and changes in road use, county and township highway departments face decisions on whether to maintain existing surface types, to upgrade them to accommodate increasing vehicle traffic and user expectations, or to downgrade them to reduce construction and maintenance costs. The decisions are primarily economic, but costs may depend on a variety of factors, including traffic volume, truck traffic volume, existing surface type and condition, terrain, soil type, climate, availability of materials, and ancillary maintenance costs. Existing geometric conditions and the need for geometric improvements may limit or complicate available alternatives. The decisions may depend on public concerns such as safety, vehicle wear, and dust control which also have economic implications. Finally, because of funding constraints, decisions may depend as much on initial costs as on life-cycle costs for the surfacing alternative. Especially in areas of rapid population expansion or of depopulation, these decisions can be politically contentious.
R esearch is needed to help local government agencies assess the economic tradeoffs between maintaining existing highway surfaces and upgrading or downgrading surface type to match users' needs and expectations. The research should produce criteria and methodology for the assessment, as well as recommendations based on application of the methodology to typical South Dakota conditions.