N.J. Stat. § 27:16-15
When a county road is not built and improved to its authorized or full width and in the judgment of the board of chosen freeholders it is desirable that it be so built and improved for the accommodation of public travel, the board may, upon the affirmative vote of at least three-fourths of all its members, so build and improve it.
If a street railway company has its rails laid on the road or any part thereof, the board may enter into an agreement with the company whereby the company, in consideration of the work being undertaken, will bear and pay a portion of the cost thereof. If the road is crossed by a steam railroad at grade the board may enter into an agreement with the railroad company owning or operating such steam railroad and the street railway company using the road, to change the grade of the road or tracks of the steam railroad and abolish the grade crossing, in the manner provided by law, and the funds for these purposes shall be raised by the board in the manner provided by section 27:16-19 of this title.
N.J.S. § 27:16-15