It shall be the duty of the county engineer to do all of the following:
(1) To employ, supervise, and direct all assistants as are necessary properly to maintain and construct the public roads, highways, bridges, and ferries of Lawrence County, and he or she shall have authority to prescribe their duties, and to discharge employees for cause, or when not needed.
(2) To perform such engineering and surveying service as may be required, and to prepare and maintain the necessary maps and records.
(3) To maintain the necessary accounting records to reflect the cost of the county highway system.
(4) To build, or construct new roads, or change old roads, but only when ordered to do so by proper order of the county commission.
(5) It shall be his or her further duty, insofar as is feasible to construct and maintain all county roads on the basis of the county as a unit, without regard to any district or beat lines.