Pursuant to 1995 Public Law 157, and the adoption of amendments to N.J.A.C. 7:27- 14: Control and Prohibition of Air Pollution from Diesel-Powered Motor Vehicles and N.J.A.C. 7:27B-4: Air Test Method 4: Testing Procedures for Motor Vehicles, New Jersey implemented its Heavy-Duty Diesel Emissions Program (HDDVIP) in two phases for non-Diesel bus or school bus vehicles with a Gross Vehicle Weight Rating (GVWR) of greater than 8,500 lbs. Phase One introduced a roadside enforcement program with an enhanced variant of the existing self-inspection program as well as a mechanism to provide for voluntary inspections. Phase Two commenced with a periodic exhaust emissions test conducted by licensed inspection centers, and maintains the roadside enforcement program.