Lately, we’ve seen increased complaints and news stories about drivers rolling coal on roads nationwide. Like any hot-button topic, there are always two sides to every discussion, and it seems neither side wants to listen to what the other has to say.
Whether you’re one of the coal rollers or have no idea what it means, it’s a crucial discussion worth having.
Today, we’re looking at the divide between truck owners for drivers rolling coal.
What Does Rolling Coal Mean?
“Rolling coal” is a term people use to refer to drivers modifying their diesel engines to produce large plumes of black smoke from their exhaust. When a driver hits the accelerator, it dumps a high amount of fuel into the engine, creating smoke from the exhaust system.
If you see a vehicle at a stoplight or on the highway emit a copious amount of dark smoke, they’re likely rolling coal intentionally. However, not everyone is happy when drivers operate their vehicles in this manner.
It comes as no surprise that the increased pollution doesn’t sit well with environmentalists. As a result, the practice is very controversial and divisive in the driving community.

Do All Diesel Engines Smoke?
No, not all diesel engines emit black smoke. In fact, a properly operating engine should not smoke at all. The black smoke is usually a result of incomplete combustion, which can be caused by various factors such as low-quality fuel, incorrect air-to-fuel ratio, or malfunctioning injectors. In most cases, these days the smoke you see from trucks is due to intentional modifications that create it.
Modern diesel engines have been designed to reduce or eliminate black smoke emissions through various technologies such as high-pressure fuel injection systems, exhaust gas recirculation, diesel particulate filters, and selective catalytic reduction.
However, older diesel engines or poorly maintained diesel engines may still emit black smoke. Our 1980 backhoe smokes a lot under load, but it always did. It’s important to properly maintain diesel engines and use high-quality fuel to reduce emissions and keep the engine running efficiently.
We once had a failing DPF in our first diesel truck that caused lots of smoke upon accelerating. Once getting it fixed the truck went back to running clean.
What Is the Point of Rolling Coal?
Rolling coal occurs naturally on the diesel racetrack. The more fuel you pump into the engine, the more smoke it generates. Thus when pushing the performance of a diesel engine, smoke will occur. This practice is often associated with some truck and car enthusiasts who do it as a way of showing off their vehicle’s power, performance, and dominance on the road.
Many drivers also do it to show off, attract attention, and put on a little show for their friends. However, some are even trying to send a political message to others. Some individuals may also roll coal to protest environmental regulations or to express their dissatisfaction with certain groups of people, such as bicyclists or pedestrians, who they feel are encroaching on their driving space. Rolling coal may also be seen as a form of rebellion against mainstream culture or as a way to display one’s identity or belonging to a particular subculture.
Many people don’t particularly enjoy it and respond negatively to any signs of it. Lately, we’ve seen a push for a change to electric vehicles. Some coal-rolling drivers will pull up beside electric vehicles and release a plume of smoke in front of the car to send a message. Some drivers express their freedom to oppose the political idea of using cleaner vehicles.
Pro Tip: Make your truck unique by using our guide on What Mods You Should Do to Your Truck First.

Is Rolling Coal Illegal in the US?
The legalities of rolling coal are somewhat tricky. This is because these types of regulations and laws vary by state. Maine, Utah, New Jersey, Maryland, Colorado, and Connecticut ban drivers from rolling coal. However, the federal government also has something to say about the practice.
In July 2014, the EPA (Environmental Protection Agency) unsurprisingly opposed rolling coal. They stated that the practice violated the Clean Air Act of 1963. In their defense, they have a solid argument.
The Clean Air Act prohibits the manufacturing, sale, or installation “of a part for a motor vehicle that bypasses, defeats, or renders inoperative any emission control device” and “prohibits anyone from tampering with an emission control device on a motor vehicle by removing it or making it inoperable prior to or after the sale or delivery to the buyer.”
More and more complaints are also landing some coal rollers in lawsuits claiming personal injury. Also, many companies that have been selling products that allow drivers to roll coal have been heavily targeted and fined.
Is Rolling Coal Making Pollution Worse?
An individual truck modified to roll call pollutes far worse and more than a standard diesel truck. In densly populated areas they sure don’t help with air quality and their emissions are particularly toxic. However, in the grand scheme of pollution problems, the (statistically) few people rolling coal are not going to make much of an impact compared to overall emissions. The emissions from manufacturing, energy generation, and transportation of the products we buy are a far larger problem; however, we don’t see them.

Can Only Diesel Trucks Roll Coal?
Diesel trucks don’t naturally roll coal. It requires some modification. Additionally, a gas truck can roll coal, but it needs you to add extra fuel to the engine and ignite it. However, the smoke gasoline engines create isn’t as intense as diesel engines.
In addition to violating the Clean Air Act, you’ll have to significantly modify the engine and exhaust system to make it happen. Not only do you risk getting yourself in serious legal trouble, but you could also damage your vehicle.

How Do You Roll Coal?
Drivers can roll coal in their diesel trucks in a few common ways. Usually through the use of electronic tuners or modules, but also via physical modifications to the engine.
Tuners and Modules
This is one of the easiest ways for a diesel truck to roll coal. Tuner and module devices change how much fuel and air an engine receives. By changing the parameters to decrease the turbo and increase fuel, vehicles produce a thick cloud of smoke from their exhaust during hard accelerations.
Keep in mind that most of these require removal of part of the emmissions system on modern trucks or catastrauphic failure of the system and damage will result.
Smoke Switches
A smoke switch is basically another version of a tuner connected to a physical switch. This changes the engine’s tune at the flick of a switch. The switch sends more fuel to the engine. The results are an on-demand, thick cloud of smoke and angry bystanders, especially if they’re not expecting the spectacle.
Physical Engine Modifications
Another way to create these smoke plumes is by physically modifying the engine. One of the first steps is to defeat or remove the environmental controls on the engine. Many call this “deleting” the truck. Beyond this performance, mods can allow further fuel to get into the engine.
Installing larger injectors and changing the tune on your vehicle. The injectors are devices that pump fuel into an engine. By changing the tune, the engine believes it needs more fuel. This is one-way racers get more power out of their engines.
Since you’re physically modifying the engine, you must know what you’re doing. If not, you could cause some severe damage to your vehicle. If that’s the case, you’ll need deep pockets and prepare to spend a pretty penny on a new engine.
Pro Tip: We compared Diesel vs. Gas Trucks: Which Is Better for Towing to help you decide which truck is right for you.
Why You Shouldn’t Roll Coal
Even if you like the way it looks, there are several reasons you should avoid rolling coal. Let’s dive in and see!
Not Good For the Engine
Unless modifications are done properly, injecting too much fuel into an engine can cause problems. From sooting up oil and injectors to overheating and warping heads, a lot of damage can occur. Not to say a proper modification won’t cause problems, but we have heard of more than one “smoke tune” causing major problems.
Negative Appearance to Most
Generally, most people find rolling coal to be gross and unappealing. It’s unnecessary, and many see it as a somewhat immature action. Not only are you wasting fuel, but you’re also creating a scene for everyone in the area.
However, this is the reason why many people choose to roll coal. They may enjoy the attention and upsetting others. Many of these drivers look for opportunities to trouble others by blowing smoke.

Health and Safety Risks
You never know what underlying health conditions people around you might have. Exhaust fumes can induce respiratory issues for some individuals, so you and your smoke could cause serious medical problems for them. Additionally, the American Cancer Society states there are strong connections between diesel exhaust and cancer.
If that’s not enough, these large smoke plumes can make it hard for drivers to see. They could hold you responsible if the exhaust from your vehicle obstructs a driver’s view and causes an accident. Do you want that on your hands?

Increased Pollution
While vehicle manufacturers have come a long way in reducing the amount of pollution from vehicles, it still exists. However, rolling coal drastically increases the amount of pollution in a car. Every time a driver stomps on the accelerator aggressively, they unnecessarily release much pollution into the environment.
It Might Be Illegal
Since the rules and regulations vary by state, you could be in legal trouble by rolling coal. Even if it’s not a state law where you live, the Clean Air Act prohibits tampering with an emission control device on any vehicle.
Some states are even instituting reporting programs to help identify potential violators. Depending on where you live, you could receive a fine of $250 or more. You’ll likely start questioning whether it’s worth it when it impacts your bank account.
To Roll Coal or Not to Roll Coal?
Rolling coal is a very controversial topic. Some drivers feel it shows off the power and performance of their vehicle or makes a political statement. However, others see it as a harmful and dangerous practice that needs to stop.
We stand somewhere in the middle on this one. While we feel its fine to smoke when pushing performance using it on the roadway with the intention to annoy or create mayham is rude. We’ve enjoyed the power of diesel engines in multiple motorhomes and pieces of heavy machinery we have owned over the years. However, we also feel a responsibility to help protect and care for the environment while exploring it.
Would you modify your vehicle to roll coal? Tell us your thoughts in the comments!
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Not So Free
Monday 3rd of April 2023
I have a name for peole who do this, but I can't print it here on a family site.
Andy
Sunday 11th of June 2023
@Not So Free, they're called mamatruckers!
Joel
Saturday 1st of April 2023
Several of your pics show burnouts which means the smoke is at least partially from burning rubber. Also, how old and where is the pic of coal burning stacks? EPA requires scrubbers in modern U.S. coal plants. I think most readers, including myself, are fairly neutral on many subjects and tend to steer away from sources that appear biased or untrustworthy. Careful with your picture selection please. That said, I've found your newsletter generally helpful and informative, especially when it comes to electrical systems which appear to be your specialty. Keep up the great work! Thank you.
p.s. I also enjoy your coverage of expeditions; i.e. Alaska, Mexico...