N.J. Stat. Ann. § 27:7-11

The commissioner shall take charge of all work on state highways and maintain them in good order. All work of improvement, betterment, reconstruction, or resurfacing shall be done in accordance with plans and specifications prepared by the department. All work of maintenance, repair and extraordinary repair shall be done at the expense of the state and may be done either as an independent contractor or employer or through contracts made in the name of the state.