Once a road's design is finalized and any necessary property has been acquired, the S.C. Department of Transportation advertises for construction bids. Bids are publicly opened on a specified date. In compliance with state law, the Secretary of Transportation then awards the contract to the lowest responsible bidder—a private contractor who must complete the work according to the approved plans and specifications.

An alternative method, known as “design-build,” involves awarding a single contract to a combined team of designers and builders. Selection is based on both technical proposals and cost. Under this approach, one contract covers design, environmental permitting, right-of-way acquisition, utility relocation, and construction. By consolidating these elements, design-build typically shortens overall construction time, helps avoid cost inflation, and allows the contractor to innovate—resulting in cost savings, reduced environmental impact, and fewer traffic disruptions.

Projects may be considered for design-build if they meet one or more of the following criteria:

• They need an expedited schedule (either for the public good or to utilize specific funding opportunities).
• They are emergency projects.
• They present challenging construction or traffic phasing conditions.
• They offer opportunities for innovative solutions.
• They are atypical projects that do not fit standard design-bid-build procedures.

Examples of projects well-suited to the design-build process include new roadways, major interstate expansions or rehabilitations, those carrying heavy traffic, and large or unique bridge projects.

Once a contract is awarded, SCDOT’s Division of Highways oversees it. A resident engineer and their staff manage day-to-day operations, interpret the project plans, ensure adherence to contract requirements, conduct quality tests, and record the amount of work performed for monthly contractor payments. They also protect the environment, manage traffic flow, work with nearby property owners, monitor work zone safety, and coordinate with state and federal agencies.

Before a road opens to traffic and the project is officially complete, an independent SCDOT team conducts a final inspection to confirm that the work meets all required standards.