N.J. Stat. § 27:22-14: Agreement; approval by county

When a township applies to the board of chosen freeholders for an improvement to be made under section 27:22-13 of this title, an agreement shall be entered into between the township and the county specifying the amount that each shall contribute towards the improvement of the road, and the nature of the work to be done. After the execution of the agreement, the township may proceed to make the improvement, in compliance with the laws under which similar works are undertaken, contracted for and executed in the township.

The work shall be subject to the approval of the county engineer of the contracting county and if approved by him the board of chosen freeholders shall pay its share of the cost according to the terms of the agreement.