New Jersey Statutes Title 39. Motor Vehicles and Traffic Regulation 39 § 4-98.2

Any county or municipal governing body may adopt an ordinance or resolution, as appropriate, designating a county or municipal official who may order a reduction of a regular speed limit for periods not to exceed 72 hours on segments of highways under its jurisdiction for the purpose of maintenance or repairs.  Any resolution or ordinance adopted pursuant to this act shall specify the circumstance under which a speed limit may be reduced.

An order reducing the speed limit pursuant to this act shall not require the approval of the Commissioner of Transportation;  provided, however, that it shall be the duty of the designated county or municipal official to notify the commissioner of the affected segment of highway no less than 7 days before any reduced speed limit takes effect;  except that in cases of emergency situations the notification period may be waived by the commissioner.  It shall be the duty of the designated county or municipal official to place one or more signs indicating the reduced speed limit along the affected highway.

Any speed limit established pursuant to this act shall be prima facie lawful and subject to the provisions of R.S. 39:4-96 and 39:4-97 when appropriate signs giving notice thereof are erected.