N.J. Stat. Ann. § 39:3-54.20

Any person authorized to display red emergency warning lights, sirens, or both, pursuant to this act, who willfully displays or uses the lights or sirens in violation of the provisions of this act, shall be liable to a penalty of not more than $50.00 and his privilege to display the lights or sirens may be suspended or revoked by the Director of the Division of Motor Vehicles.