# "Coal Rollers:" can they be charged with assault? **URL:** \ **Category:** Factual Questions\ **Created:** [July 8, 2014, 10:23pm UTC](https://boards.straightdope.com/t/coal-rollers-can-they-be-charged-with-assault/692669 "2014-07-08T22:23:02Z")\ **Posts on this page:** 12\ **Page:** 8
**Author:** ![joema](https://avatars.discourse-cdn.com/v4/letter/j/a9adbd/32.png) [@joema](https://boards.straightdope.com/u/joema)\ **Post date:** [September 6, 2016, 1:17pm UTC](https://boards.straightdope.com/t/coal-rollers-can-they-be-charged-with-assault/692669/141 "2016-09-06T13:17:25Z")
> [@eschereal](#): > > That appears not to be the case. In most normal use, the “coal rollers” appear to put out a typical exhaust stream, and would easily pass most emission tests. I think the modification allows for selective fuel dumping (into the engine) whenever the driver wants to billow. There is more involved than this, but I haven’t seen any article discuss it. Many states and counties requiring emissions testing don’t use tail pipe sniffing but plug-in OBD II testing – often annually. Relatively modest ECU modifications (so-called “stage 1”) will generally pass these tests. The vehicle ECU itself which reports whether emissions are within limits. I believe overriding this reporting feature is a felony so even avid performance enthusiasts don’t do that. However just modifying the engine or software is at most an emissions violation, much less serious, so this is commonly done. Going beyond stage 1 generally requires modification to the downstream O2 sensors otherwise a “check engine light” (CEL) will be generated. However modifying those or disabling them in software will cause plug-in OBD II emissions tests to fail with the error “readiness monitors not set”. This status can be reset with a scan tool but it then will immediately recur if the ECU software is not changed, and if O2 sensors are put back on line a CEL will happen. So the thing never discussed in all these articles are how the “coal rollers” generate such massive differences in engine operation yet still pass plug-in OBD II testing. Maybe someone more knowledgeable can elaborate. It’s possible diesel-powered light trucks may have less stringent emission testing requirements, so the whole thing with CEL and O2 sensors may not apply to them. If so this would be a regulatory loophole the owners have simply exploited. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [September 6, 2016, 1:30pm UTC](https://boards.straightdope.com/t/coal-rollers-can-they-be-charged-with-assault/692669/142 "2016-09-06T13:30:33Z")
> [@davidm](#): > > I suppose that there will always be bullies. Some people never really grow up. Spotted elsewhere on the internet: \*\*"Humans are [Deuterostomes](https://en.wikipedia.org/wiki/Deuterostome), which means that when they develop in the womb, the anus forms before any other opening. Which basally means that at one point, you were nothing but an asshole. Some people never develop beyond this stage."\*\* ---
**Author:** ![Duke\_of\_Rat](https://avatars.discourse-cdn.com/v4/letter/d/ad7895/32.png) [@Duke\_of\_Rat](https://boards.straightdope.com/u/Duke_of_Rat)\ **Post date:** [September 6, 2016, 2:25pm UTC](https://boards.straightdope.com/t/coal-rollers-can-they-be-charged-with-assault/692669/143 "2016-09-06T14:25:16Z")
> [@davidm](#): > > I thought that this was a stupid fad that came and went. > I suppose that there will always be bullies. Some people never really grow up. Like the train horn guys, but I think they eventually get at least ticketed for improper horn use or something like that. [![](https://img.youtube.com/vi/2kDORB3vR8s/hqdefault.jpg "THE BEST OF TRAIN HORN PRANKS #2") ](https://www.youtube.com/watch?v=2kDORB3vR8s) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 6, 2016, 2:42pm UTC](https://boards.straightdope.com/t/coal-rollers-can-they-be-charged-with-assault/692669/144 "2016-09-06T14:42:57Z")
> [@](#): > > Quoth **joema** : > > Many states and counties requiring emissions testing don’t use tail pipe sniffing but plug-in OBD II testing – often annually. Wow, if you mis-read that last word, it really changes the meaning of that sentence. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [September 6, 2016, 10:10pm UTC](https://boards.straightdope.com/t/coal-rollers-can-they-be-charged-with-assault/692669/145 "2016-09-06T22:10:56Z")
> [@joema](#): > > … > So the thing never discussed in all these articles are how the “coal rollers” generate such massive differences in engine operation yet still pass plug-in OBD II testing. Maybe someone more knowledgeable can elaborate. > > It’s possible diesel-powered light trucks may have less stringent emission testing requirements, so the whole thing with CEL and O2 sensors may not apply to them. If so this would be a regulatory loophole the owners have simply exploited. It’s dirt-simple. They use the same technique as airshow airplane smoke. Using a dedicated electric pump you inject oil into the exhaust plumbing downstream of all the emissions sensors. You want a super-rich mess of warmed & partly burned fuel, not nice lean burning. Leave the whole engine and emissions and exhaust system box-stock. ---
**Author:** ![Savannah](https://avatars.discourse-cdn.com/v4/letter/s/b3f665/32.png) [@Savannah](https://boards.straightdope.com/u/Savannah)\ **Post date:** [September 7, 2016, 12:41am UTC](https://boards.straightdope.com/t/coal-rollers-can-they-be-charged-with-assault/692669/146 "2016-09-07T00:41:35Z")
> [@Hail\_Ants](#): > > Personally I find it funny way of giving the proverbial finger to certain oh-so pretentious Prius owners! 😃 Funny? It can blind the driver whilst driving, and it also been done to cyclists and pedestrians. Anyone who thinks this is “funny” is a juvenile ass of the lowest order. It’s being a fucking asshole, not being “funny.” ---
**Author:** ![Savannah](https://avatars.discourse-cdn.com/v4/letter/s/b3f665/32.png) [@Savannah](https://boards.straightdope.com/u/Savannah)\ **Post date:** [September 7, 2016, 12:47am UTC](https://boards.straightdope.com/t/coal-rollers-can-they-be-charged-with-assault/692669/147 "2016-09-07T00:47:56Z")
Too late to edit, so I will add: I responded to Hail Ants’ post before continuing on and reading the rest of the thread. I see there is a moderator note. I assume that my opinion is shared by others, and has already been expressed, therefore, consider it that I’m “deleting” the post. ---
**Author:** ![Urbanredneck](https://avatars.discourse-cdn.com/v4/letter/u/ea5d25/32.png) [@Urbanredneck](https://boards.straightdope.com/u/Urbanredneck)\ **Post date:** [September 7, 2016, 2:17am UTC](https://boards.straightdope.com/t/coal-rollers-can-they-be-charged-with-assault/692669/148 "2016-09-07T02:17:56Z")
This conservative would be calling the cops immediately if I saw this. ---
**Author:** ![UltraVires](https://avatars.discourse-cdn.com/v4/letter/u/ecccb3/32.png) [@UltraVires](https://boards.straightdope.com/u/UltraVires)\ **Post date:** [September 7, 2016, 2:52am UTC](https://boards.straightdope.com/t/coal-rollers-can-they-be-charged-with-assault/692669/149 "2016-09-07T02:52:19Z")
> [@Bricker](#): > > And you have some case law for this “intimately associated” thing you’ve read into the law? Or the proposition that a car is “intimately associated” in the first place? > > Because I would love to defend against that charge with that fact pattern. I know this is two years old, but doesn’t the common law define battery as contact with something “intimately associated” with the person? If I slap a notebook out of your hand, never making contact with your hand or any other part of your person, I have committed a common law battery, have I not? The WV statute has since changed, requiring “force capable of causing physical pain,” but there is no case law to date on what quantity of pain might be sufficient. I agree that there could be defenses to the charge, but if I were a prosecutor, I would argue that the first driver intentionally caused the smoke (filled with some solid particles) to make a contact of an offensive nature, with something intimately associated with the motorist (his car, on a public road, offering his only protection), hence a battery. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [September 7, 2016, 11:25am UTC](https://boards.straightdope.com/t/coal-rollers-can-they-be-charged-with-assault/692669/150 "2016-09-07T11:25:24Z")
> [@joema](#): > > So the thing never discussed in all these articles are how the “coal rollers” generate such massive differences in engine operation yet still pass plug-in OBD II testing. Maybe someone more knowledgeable can elaborate. The exhaust system of late-model diesel vehicles includes a [diesel particulate filter (DPF)](https://en.wikipedia.org/wiki/Diesel_particulate_filter). This is a ceramic filter designed to capture the vast majority of the soot in the exhaust stream. It also has a catalyst coating on it, and after X hours of operation, when it’s starting to get clogged up, the engine’s computer adjusts operation so that the exhaust runs hot, and/or also adds a spritz of raw fuel to the exhaust. This, combined with the DPF’s catalyst, lights off the soot in the DPF so that it smolders away over the next half-hour or so of operation, leaving the filter almost as clean as new (though I understand incombustible ash does slowly accumulate over time, eventually requiring removal and cleaning). It’s possible to buy a [“DPF delete” kit,](https://www.google.com/?gfe_rd=ssl&ei=Q_fPV-euO4W--wWk0Y3ACA#q=dpf+delete) which provides the parts necessary to replace the DPF with a simple bare pipe. Coal rollers do this, and then go one step further, applying a tweak to the engine computer so that it always thinks full turbo boost is being applied, and will therefore happily inject large quantities of fuel as soon as the driver puts his foot to the floor. With the engine running extremely rich, the engine produces massive amounts of soot, and with no DPF to catch it, it ends up all over the Prius in the next lane. Most states do not perform emissions inspections of any kind; coal rollers in those states can, at present, operate without fear of enforcement actions. > [@LSLguy](#): > > It’s dirt-simple. They use the same technique as airshow airplane smoke. This would generate pretty white smoke, just like the airshows. ---
**Author:** ![joema](https://avatars.discourse-cdn.com/v4/letter/j/a9adbd/32.png) [@joema](https://boards.straightdope.com/u/joema)\ **Post date:** [September 7, 2016, 12:56pm UTC](https://boards.straightdope.com/t/coal-rollers-can-they-be-charged-with-assault/692669/151 "2016-09-07T12:56:03Z")
> [@Machine\_Elf](#): > > …Most states do not perform emissions inspections of any kind; coal rollers in those states can, at present, operate without fear of enforcement actions… I believe 32 out of the 50 states plus DC require emissions testing. The question is (still unanswered) whether diesel-powered light trucks are exempt from this or maybe tested via a different method or to a less stringent standard. In those states with testing, it’s not “fear of enforcement” as if you’d get pulled over and given a ticket. Rather at the annual emissions test if your vehicle doesn’t pass you can’t renew your registration, get no license plate or window stickers and cannot legally drive it. LSLGuy says “coal rollers” leave the engine, emissions and exhaust system totally stock and crudely inject fuel into the exhaust stream. That would answer the question, but do they all do it that way? ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [September 7, 2016, 2:48pm UTC](https://boards.straightdope.com/t/coal-rollers-can-they-be-charged-with-assault/692669/152 "2016-09-07T14:48:05Z")
> [@joema](#): > > I believe 32 out of the 50 states plus DC require emissions testing. The question is (still unanswered) whether diesel-powered light trucks are exempt from this or maybe tested via a different method or to a less stringent standard. That leaves [18 states with no emissions checks at all](https://en.wikipedia.org/wiki/Vehicle_inspection_in_the_United_States) and at least 18 others (hard to count the small ones on that map) in which only some areas are subject to emissions checks. That’s a whole lot of area where trucks can be permanently modified with impunity. > [@joema](#): > > In those states with testing, it’s not “fear of enforcement” as if you’d get pulled over and given a ticket. Rather at the annual emissions test if your vehicle doesn’t pass you can’t renew your registration, get no license plate or window stickers and cannot legally drive it. :dubious: “Can’t register/drive my truck because of non-compliant emissions” counts as an enforcement action in my book. > [@joema](#): > > LSLGuy says “coal rollers” leave the engine, emissions and exhaust system totally stock and crudely inject fuel into the exhaust stream. That would answer the question, but do they all do it that way? Google [how to roll coal](https://www.google.com/?gfe_rd=ssl&ei=ByLQV8mbFIqI-QXX9IrYAg#q=how+to+roll+coal); I don’t think any of them are doing it that way. Hot exhaust will vaporize/atomize oil and make a nice white cloud, but you need to partially combust fuel to release the raw carbon that makes nice black soot. That requires putting the fuel (too much of it) into the engine’s combustion chambers, not directly into the exhaust. And you won’t let much of that smoke out of the tailpipe unless you get rid of the DPF. [Previous page](https://boards.straightdope.com/t/coal-rollers-can-they-be-charged-with-assault/692669.md?page=7)