This comment is regarding…

This comment is regarding opacity. I believe a properly tuned diesel engine regardless of year, should not emit more then 10% opacity, as a diesel mechanic, I see vehicles that pass with less then 5% opacity. 20% is still a significant amount of particulate emitting from a vehicle. Furthermore, the test is at stand still. Imagine a vehicle that passed with 20% opacity operating on the roadway with a heavy load. That 20% will increase to 50% plus. I have witnessed it. Furthermore, when It comes to Enforcement, that vehicle that was stopped and charged for emitting 50% opacity for 15 sec; will turn around, obtain a Drive Clean test at stand still for 19% opacity pass, go to court and have his charge thrown out, because it met the Drive Clean standards. NO vehicle, regardless of Light Duty, heavy Duty, school bus, whatever, should emit more then 10% opacity. I should note I am also an Environmental Technologist. As a mechanic I have seen and inhaled noxious particulate and NOX, and as an Environmentalist, I know what that particulate and VOC, NOX can do to human health. Furthermore, I believe LD vehicles should still be a major focus. I cant tell you how many times I have been behind a tuner car with absent emission controls or jacked up diesel pick up that has been modified to emit excessive emission, and have my kids and myself covering our eyes and our mouths not to inhale there exhaust emissions. Take a drive up North, its all jacked up diesel pick ups with missing emissions and belching out black emissions because it is cool. Thank you