If my car fails while I'm driving through the desert and leaves me stranded in 100+ degree heat in the summer, that would be a critical situation.
If my car fails while I'm driving on a busy part of I5, that could be a critical situation.
I get that the rolling coal mods or whatever aren't designed to improve reliability, but things like deleting EGR or modifying the control logic for the DEF system are and can prevent a vehicle from failing in a situation that could be life threatening. Again, the government already knows this which is why they order their vehicles with those exact modifications already done.
If you're talking about black smoke out of the exhaust, no it doesn't help reliability. If you just mean tuning to optimize not for emissions, yeah it can help if you know exactly what you're doing or screw it up if you don't, either way you'll only find out later. Doesn't seem to matter because most professionals already make their living without messing with their trucks.
idk who downvoted you, that's not appropriate, so +1'd you to avoid comment death
The fact is, emissions regulations in many ways have nothing to do with health or clean air. I don't drive a diesel truck myself so its not like I'm trying to defend my own behavior or anything. I'm a former automotive engineer who is unfortunately very familiar with the regulations and how nonsensical they are.