Change in NO_x Emissions by Vehicle Class 1970-2002

	1970	2002
Light-Duty Gas Vehicles & Motorcycles	8542	2,166
Light-Duty Gas Trucks	1540	1,401
Heavy-Duty Gas Vehicles	723	404
Heavy-Duty Diesel Truck	1764	3,378

Change in NOx Emissions by Vehicle Class 1970-2002