N.J. Stat. § 27:23-27
A person operating a vehicle on any such highway project shall operate it at a careful and prudent speed, having due regard to the rights and safety of others and to the traffic, surface and width of the highway, and any other conditions then existing; and no person shall operate a vehicle on any such highway project at such a speed as to endanger life, limb or property; provided, however, that it shall be prima facie lawful for a driver of a vehicle to operate it at a speed not exceeding a speed limit which is designated by the Authority as a reasonable and safe speed limit, when appropriate signs giving notice of such speed limit are erected at the roadside or otherwise posted for the information of operators of vehicles.
No person shall operate a vehicle on any such highway project at such a slow speed as to impede or block the normal and reasonable movement of traffic except when reduced speed is necessary for safe operation thereof.
No person shall operate a vehicle on any such highway project in violation of any speed limit designated by regulation adopted by the Authority as hereinafter provided.
N.J.S. § 27:23-27