Rolling coal

File:F-450 coal rolling Monster.jpg

A Ford F-450 monster truck "rolling coal", or blowing large clouds of dark grey diesel smoke.

Rolling coal is the practice of intentionally disabling the Clean Burn Programming of a computer controlled diesel engine, so that the vehicle can emit an under-aspirated sooty exhaust that visibly pollutes the air. It also 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 $200 to $5,000.

Rolling coal is a form of conspicuous air pollution by anti-environmentalists: "a very public way for conservative drivers to simultaneously broadcast that they aren't worried about whether humans are the cause of global warming and to openly mock the people who are." Targets of coal rolling often include owners of hybrid vehicles (hence the nickname "Prius duster") as well as foreign vehicles, bicyclists and pedestrians. In addition to environmentalism concerns, it's been noted that this phenomenon also has health risks associated with it, particularly respiratory issues, as well as safety, as the black coal can make visibility difficult.

In March 2015, Illinois General Assembly Representative Will Guzzardi published a bill proposing to impose a $5,000 fine on anyone who removes or alters their vehicle's EPA emissions equipment. Guzzardi has made it clear that "The fine would come on top of any penalties enforced by the current law that prohibits emissions tampering." In May 2015, New Jersey Governor Chris Christie signed a bill into law which prohibits retrofitting diesel-powered vehicles to increase particulate emissions for the purpose of coal rolling. Those found in violation are subject to a fine by the state's Department of Environmental Protection. The bill was introduced by state Assemblyman Tim Eustace after a pickup truck blasted smoke at Eustace's Nissan Leaf while driving.