The duty of maintaining and keeping in repair every road so laid out and opened, taken over, or acquired, shall devolve exclusively upon the board of chosen freeholders, and all other duties and all powers respecting such road shall be imposed upon and be vested in it, but when a road is acquired in accordance with section 27:16-5 of this title nothing herein contained shall divest any municipality in which the road or any portion thereof may be, or through which it may extend, of its authority to light such road, or its power to construct, grade, curb, pave or repair the sidewalks and curbs along it, nor shall this power of the municipalities divest the board of chosen freeholders of its right to construct across or under the sidewalks of the road the necessary culverts or other structures for the proper drainage, protection and maintenance of the road.

The board of chosen freeholders shall not grant an easement, right of way, or use in, under or over, any portion of a county road in a municipality, unless the governing body of the municipality, or the board of public utility commissioners, shall consent thereto. When, in connection with any such grant, the consent of property owners is required by law, it shall be obtained before such grant of any such easement, right of way or use.