In a truck pull competition, excessive clouds of diesel smoke are a byproduct of the truck's functionality. But coal rollers have taken this idea from the county fair to the public roads -- all in the name of making people angry. Read more »
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Leech, Planet Green, Eric J.. "Top 7 Ways to Reduce Your Driving Emissions without Reducing Quality of Life" 06 December 2011. HowStuffWorks.com. <http://auto.howstuffworks.com/emissions-reduction-tips.htm> 26 April 2015.