New Jersey Statutes Title 27. Highways 27 § 9-1

The board of chosen freeholders of any county in which a state highway route has or shall have been laid out by the state highway commissioner may, with the consent of the commissioner, construct and improve the whole or any part of the highway within the county.

The construction and improvement shall be in accordance with plans and specifications submitted by the board of chosen freeholders and approved by the commissioner, and shall be conducted by the board of chosen freeholders at all times subject to the inspection of the commissioner.

A contract for the construction or improvement of a highway made by a county under this section and sections 27:9-2 to 27:9-5 of this title shall not be effective until approved by the commissioner both as to character and cost of work and materials, and shall provide that no payment shall be made thereunder to any contractor except on the certificate of the county engineer, countersigned by the state highway engineer, certifying that the work for which payment is claimed has been done in all respects in accordance with the contract and with the plans and specifications.