After seeing this article, disapproving of folks rolling coal, I figured I had to post this video.

http://www.vocativ.com/culture/society/dicks-pick-trucks-meme-rollin-coal/

Honestly, I don't see what the big deal is. It's only a small number of folks who have modified their diesel trucks this way with smoke switches or aggressive tunes, and typically rolling coal is only a very small portion of the time the vehicle is operating (e.g. when the smoke switch is activated). The effect may be dramatic, and cover things with soot, but environmental impact in grand scheme of things is zero.

http://www.dieselhub.com/tech/how-to-blow-black-smoke.html

Should have bought a diesel truck. Except diesels are expensive, more difficult to maintain, and but an more expensive fuel that is harder to get especially in rural areas.