N.J. Stat. § 27:7-6
Upon such determination by the commissioner such route or part thereof shall become a state highway, and the further improvement, betterment, maintenance and repair thereof shall be at the expense of the state, under the jurisdiction of the commissioner, but when the determination of the commissioner or any amendment thereof made before the work on such portion of a state highway has been begun, shall contain a provision that certain indicated portions of a state highway to a length thereof in any particular location not exceeding five miles are subject to change of route at any time thereafter, which change is hereby limited to five years from the completion of such highway in its entirety as originally laid out, the certain indicated portion or portions thereof shall not become permanently dedicated as a part of the route of such state highway, but the commissioner may, in that case, alter the route and lay out the new part of the route as he may indicate, as he might have done in the first instance. The vacated portion of the highway to the extent limited herein may then be either vacated or abandoned and may be taken over by the board of chosen freeholders of the county and maintained as a county road as is otherwise provided by law.
N.J.S. § 27:7-6