N.J. Stat. Ann. § 59:4-4

Subject to section 59:4-2 of this act, a public entity shall be liable for injury proximately caused by its failure to provide emergency signals, signs, markings or other devices if such devices were necessary to warn of a dangerous condition which endangered the safe movement of traffic and which would not be reasonably apparent to, and would not have been anticipated by, a person exercising due care.