N.J. Stat. § 26:2C-8.38
Notwithstanding the provisions of P.L. 2005, c. 219(C.26:2C-8.26 et al.), or any rule or regulation adopted pursuant thereto, to the contrary, no owner of any on-road diesel vehicle or piece of off-road diesel equipment may be required by the department to repower any on-road diesel vehicle or piece of off-road diesel equipment, or to replace or rebuild an engine in any on-road diesel vehicle or piece of off-road diesel equipment, unless the owner has voluntarily agreed to do so. The owner of any on-road diesel vehicle or piece of off-road diesel equipment may repower the on-road diesel vehicle or piece of off-road diesel equipment, or replace or rebuild its engine, to comply with the requirements of P.L. 2005, c. 219(C.26:2C-8.26 et al.).
N.J.S. § 26:2C-8.38