(a) Subject to the limitations of this Code section, in addition to the authority to contract with a private contractor, a county may enter into a contract with the state, a state agency, another county or municipality, or with any combination or number of the foregoing entities for work on any public road system of Georgia.

(b) Such a contract with a state agency is subject to the limitations of Code Section 32-2-61, including the cost of the negotiated contract, and the right of the department to supervise performance of the contract.

(c) A county shall have authority to enter into a contract with adjoining counties for the joint work on a road constituting a part of the county road system of those counties which are parties to such contract.

(d) A county shall have the authority provided in subsection (b) of Code Section 32-4-112 to contract with a municipality and expend funds for work on public roads within a municipality in the county.