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South Dakota Department of Transportation
Project Synopsis
SD2002-10


Title: Local Road Surfacing Criteria
Project Researcher: Katie Zimmerman, Applied Pavement Technologies
Project Manager: Paul Oien
Research Period: 9/10/2002 - 5/30/2004
Status:
Cost: $91,000.00

Problem Statement: South Dakota's local highway system consists primarily of gravel- and bituminous-surfaced roads. Historically, the more rural and less-traveled roads have been gravel-surfaced, while those carrying more traffic have been surfaced with asphalt surface treatments or thin hot mix asphalt mats. Some of the gravel surfaces are chemically stabilized.

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.



Findings:

Research Objectives:
1  To model agency costs as a function of surfacing type and other potentially significant variables such as, materials availability, structural condition, traffic, and environmental factors.
2  To model certain user costs as a function of surfacing type and other potentially significant variables such as materials availability, structural condition, traffic, and environmental factors.
3  To develop practical methodologies for using agency and user cost models to determine when to maintain, upgrade, or downgrade road surface types on local road segments.

Research Tasks:
1  Meet with the project’s technical panel to review project scope and work plan.
2  Review literature pertaining to selection of rural road surfacing type on the basis of economic and other criteria.
3  Propose, for the approval of the project’s technical panel, analytical methods for relating initial and annualized life-cycle construction and maintenance costs to surfacing type and other factors such as traffic volume, truck traffic volume, terrain
4  Propose, for approval of the project’s technical panel, analytical methods for relating select user costs such as vehicle wear and crash costs surfacing type and other factors such as traffic volume, truck traffic volume, terrain, subgrade soil type,
5  With the assistance of the technical panel, identify a sample of local highway segments in counties and townships willing to collect data necessary to calibrate the approved analytical models.
6  Provide guidelines to SDDOT and the selected counties and townships for collection of necessary data.
7  Compile and assess the quality of data collected by the selected counties and townships.
8  Analyze the collected data to calibrate the economic models to conditions typically encountered in South Dakota.
9  Recommend a practical methodology for applying the calibrated economic models for the purpose of deciding whether and when to maintain, upgrade, or downgrade surfacing types.
10  Prepare a 4-8 page Technical Brief, suitable for distribution to local agencies through the South Dakota Local Transportation Assistance Program (SDLTAP), describing the methodology and demonstrating its manual application.
11  Prepare, in spreadsheet or other suitable form, software that the South Dakota Local Transportation Assistance Program can use to analyze cases at specific locations in South Dakota.
12  Prepare a final report and executive summary of the research methodology, findings, conclusions, and recommendations.
13  Make executive presentations to the SDDOT Research Review Board and the South Dakota Association of Counties at the conclusion of the project.

Documents Available:
sd200210_Final_Report.pdf
SD200210_Technical_Brief.pdf
SD200210_Users_Guide.pdf
SD_LowVolumeSurface.xls

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