No problem. If your concern is the particulate matter, then, yes, banning old diesels makes some sense. They don't have the particulate filters - those starte

No problem. If your concern is the particulate matter, then, yes, banning old diesels makes some sense. They don't have the particulate filters - those started showing up in the 2000-2010 era. However, I would rather see that implemented as tighter standards, and if you can meet them with a retrofit kit, you can continue driving the older ones. We saw this with noise kits for older jets (retrofit kits that reduce the noise to the new standards), and if the concern is specifically emissions, then if you can make an older vehicle meet the newer standards, there's no reason to keep them out. I'm not a fan of arbitrarily destroying old but operational equipment. My truck is a '97, and I believe the smoke opacity limit for emissions testing is 40% (it's allowed to block/scatter 40% of the light going through the exhaust). I believe commercial trucks of the same age are held to roughly the same standards. That's a good bit of smoke in the exhaust. But until you get into the high pressure common rail stuff (up at 30k+ psi, multiple injections per cycle), you'll get some smoke under certain conditions.