Pollution control systems.
Trucks used blow clouds black smoke outta the smoke stacks
Nowadays they got a "DPF" Filters which clog very frequently.
Low Sulfuer Fuel and the DPF Fluid
Now when the Diesel Particulate Filter Clogs its an Engine Light and get off the road.
Get this now
Ya do a "Reset" a Re-Generation
It runs very hot and black smoke sometimes so freaking hot it can actually set Asphalt & Blacktop on fire too
Basically the DPF system collecets all the soot
But during a Regeneration Cycle bascially burns all that crap off
Was good intentions " Cleaner Air" but for Carriers and Drivers thos constant "Breakdowns" and Repair bills too which is also refleceted on the Store Shelves ya paying extra 4 it too