Originally Posted by livedarklions

Yeah, I'd go with more like a smoker blowing smoke right into your face. The health issues of it are fairly trivial.

What's worse with the rolling coal is it usually involves moving the truck in closer to the cyclist and then loudly gunning the engine, which can be pretty scary. That's obviously the intent, so it is text-book harassment. Turbulence pretty much dissipates the smoke immediately, but the close pass/loud noise is just nasty and dangerous.