The powers and duties vested in or imposed upon the boards with respect to establishing, examining, surveying, constructing, altering, repairing, improving, and maintaining county roads, shall be exercised under the supervision and direction of the county road engineer.

The board shall by resolution, and not otherwise, order the survey, establishment, construction, alteration, or improvement of county roads; the county road engineer shall prepare all necessary maps, plans, and specifications therefor, showing the right-of-way widths, the alignments, gradients, and standards of construction.