Have you ever heard the term "Rolling Coal"? It's an actual "thing" done by the same kind of people who think Hummers make them look cool.
Rolling Coal On Protesters Compilation (BlackLivesMatter, Trump Haters, Tree Huggers):
https://www.youtube.com/watch?v=rYPMbLO4pAY
https://en.wikipedia.org/wiki/Rolling_coal
>Rolling coal is the illegal practice of modifying a diesel engine to increase the amount of fuel entering the engine in order to emit large amounts of black or grey sooty exhaust fumes into the air. Rolling coal is sometimes used as a form of anti-environmentalism. Such modifications may include the intentional removal of the particulate filter. Practitioners often additionally modify their vehicles by installing smoke switches and smoke stacks. Modifications to a vehicle to enable rolling coal may cost from US$200 to US$5,000.