Mon Sep 05, 2016 1:14 am
The New York Times has an article that describes 'rolling coal' a term used to describe a diesel truck that has been modified so the muffler is disabled or the engine tuned to belch out as much smoke as possible.

http://www.nytimes.com/2016/09/05/business/energy-environment/rolling-coal-in-diesel-trucks-to-rebel-and-provoke.html