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Volkswagen Dieselgate Reexamined

Donate In the wake of VW Dieselgate, the government took the wrong steps to solve the wrong problem.  

by Brian Dunning

Filed under Consumer Ripoffs, General Science

Skeptoid Podcast #586
August 29, 2017
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Volkswagen Dieselgate Reexamined

In 2016, Volkswagen was nailed by United States regulators for a whole raft of charges related to what's become known as Dieselgate. For a decade, most of their diesel-engined passenger cars were found to have been cheating the US' stringent emissions tests. When on a testing rig, the cars had been programmed to emit clean exhaust that passed the test; but in ordinary driving, the engines would run in a different mode that produced more pollutants but gave higher performance and better fuel economy. With total penalties approaching $20 billion, it is the largest fine ever imposed by any government against any one company. Reporting has thoroughly criticized Volkswagen not only for its deadly excess pollutants, but also for its staggering hubris and dishonesty. Today we're going to take a second look, not at the ethical implications, but at the science of what took place, and the impact to the planet not only of what Volkswagen did, but of what the regulatory actions are demanding. If you've come to expect a somewhat iconoclastic view from Skeptoid, this episode is for you.

The basic facts: When the cars' software detected that its emissions were being tested, it reduced horsepower and fuel efficiency in order to produce less NOx (nitrogen oxides) and thus pass the emissions test. Nitrogen oxides are not greenhouse gases so they don't contribute to global warming, but they do contribute to acid rain and to respiratory diseases. For the fraudulent behavior and the damage to human health, Volkswagen was fined billions of dollars and is required to buy back or apply software updates to all the affected cars on the road. The angle most widely — and rightly — trumpeted by the press has been Volkswagen's astonishing hubris and callousness by causing illness and deaths in order to more profitably sell a better performing product. Rather than duplicating that part of the reporting, today I want to discuss the underlying subtleties, particular those that affect global warming, which I find to be the most important, yet virtually unreported, aspects of what happened.

I must include a conflict of interest statement at this point: I own a Volkswagen turbodiesel that is included in the scandal. I am benefitting financially by this. It was inexpensive to buy, it gets wonderful fuel economy, the insurance is cheap, and I will actually make a profit when I sell it back to Volkswagen under their mandated buyback program. I have not opted to have the software update installed, thus I am knowingly driving around in a car that exceeds allowable NOx emissions. I researched thoroughly before making this decision, and this episode is, in part, the result of that research. And I'm openly stating this as someone who, as my record at Skeptoid shows, has aggressively advocated for global warming activism through getting off of fossil fuels. If this sounds contradictory to you, then I invite you to hear me out.

I want to start by establishing two grounding principles that are going to govern my take on this subject.

  1. We need to get completely off of fossil fuels. The ultimate goal of every regulatory action taken should move us in that direction. Anything that happens in the gas or diesel worlds only makes sense if it helps move away from fossil fuels.

  2. Volkswagen was found to have violated the law. Despite feedback that I anticipate of the form "You're saying it was OK for them to cheat the emissions test!!!" I will just clear it up for you right now: No, it was not OK; and no, I'm not saying that it is. The cheating scandal and the legalities are not the subject of today's show; the science of emissions and of the regulations are; and in particular, what changes to those would make more sense from the perspective of reducing greenhouse emissions — which is what really should be the goal.

Generally, every new car has a test mode. They have to, because when a car is on a dynamometer for emissions testing, only the drive wheels turn, and the car might otherwise think it's skidding and go into some traction control mode. Test mode turns this off. To drive your Volkswagen around in the clean-burning test mode, start with the engine off and the key turned to the accessory position. Turn on the hazard lights and tap the accelerator five times. Turn the engine on, and now your Volkswagen produces cleaner emissions intended to fool the test rigs. But to drive around like that, you also need to disconnect the rear wheel sensors so the car thinks only the drive wheels are turning, as would be the case on the test rig. Nearly every new car has a mode generally comparable to this.

Consumer Reports did all of this and tested some Volkswagens in test mode against similar models in normal mode. In test mode, when the engine is optimized for cleaner emissions, the car was slower, about a half second slower zero to sixty. It also got worse fuel economy, averaging about 7% worse. This varies a lot by engine and model, but these numbers are generally representative for the largest number of affected cars. The newest affected Volkswagens, which use DEF (diesel exhaust fluid), actually do not suffer from performance or economy when running in clean mode. However, taking all the cars as a group, Volkswagen's clean mode costs performance and fuel economy.

What is this mode actually doing mechanically inside the engine? A lot. Modern engines are all computer controlled, so manufacturers are able to control whatever they want. The test mode alters the fuel pressure, the injection timing, and the recirculation of exhaust gases. Here's where it gets really complicated. Most cars change these parameters frequently during normal driving, depending on things like engine load and acceleration, to achieve the best balance between performance, economy, and emissions. All cars have software for manipulating these parameters — and they're all doing it. On the test rig, every car experiences conditions that differ from normal driving, and engine parameters change accordingly. There is no clear line differentiating what Volkswagen did, and what other diesel manufacturers do. The only real difference is that those other manufacturers didn't want to risk getting caught, so they sell no diesels, or only a very few diesel models, in the United States.

Over in Europe, it's a different story. Diesels are everywhere, because the European test, called the NEDC (New European Driving Cycle) is a lot easier to pass. And in that crowd, the same Volkswagens that we vilify here are model citizens. Diesels from Renault, Nissan, Hyundai, Citroen, Fiat, Volvo, and Jeep all fail the NEDC. Worst of all were Mercedes-Benz diesels that produce up to five times the allowed NOx, and Honda diesels that produce up to six times what's allowed. Volkswagen is not even on the map of cheating diesel manufacturers. They're not even the only ones who have been caught — Chrysler and Cummins are both also facing similar charges for doing the same thing as Volkswagen.

But let's not go down the road of "Hey, everyone's breaking the law, so it must be OK." It's not OK to break laws — but that doesn't mean that we shouldn't apply skepticism to the environmental science those laws are supposed to be defending. It is a hard science fact that modern diesels are better for the environment than gasoline cars.

Traditional diesel engines produce particulate black carbon soot, which is terrible not only for the environment but also for human health. Black carbon is not CO2. It's basically just black dust, darkening snow and absorbing heat in the atmosphere. It is a short-term contributor to warming, not a long-term contributor like CO2.

However, all new diesel cars have particulate filters that remove nearly all of this. Along with other technologies like catalytic reduction that convert the emitted NOx into harmless gases, modern diesel engines are, as a class, unequivocally cleaner than gasoline engines. Most of this difference comes from the improved fuel economy enjoyed by most diesels: less fuel burned equals less carbon emitted.

So even driving my diesel Volkswagen with its software that pollutes more but gives me better performance, I'm emitting less harmful pollutants than nearly every gasoline car around me — and even most of the other diesels, since my Volkswagen gets better fuel economy than most of them. And the biggest reason I don't take my car in for the software update is that doing so not only decreases my fuel economy, requiring me to burn more fuel and emit more, but it also increases the car's output of CO2 by about 6.5%, according to independent testing done on European cars.

So crucify Volkswagen for the hubris and their fraud, but you can't criticize them for harming the environment. We should all be driving emissions-free electric cars, but until that day comes, those evil Volkswagens are doing the planet less harm than the gasoline-powered cars most of you are driving.

And now we come to the most important point I want to make with this episode. The government's penalty against Volkswagen is actually going to make the problem worse.

There are two good things about the settlement. Volkswagen must pay $2.7 billion to upgrade old, dirty government-owned commercial diesel vehicles like buses, trucks, and locomotives. The scope of this is intended to mitigate the excess NOx produced by Volkswagens in cheat mode. Also, Volkswagen was required to create a subsidiary called Electrify America and fund it with $2 billion to do brand-neutral public outreach and build electric car infrastructure, basically charging stations.

The rest of it is all bad. Volkswagen paid a $1.5 billion civil penalty to the Environmental Protection Agency for violating the Clean Air Act, and a $2.8 billion criminal penalty to the Department of Justice. Totaling $4.3 billion, this money simply goes into government coffers. There is no reason to suspect any of it will be used to reduce emissions or mitigate either pollution or greenhouse gases, which is what should have happened.

The largest impact to Volkswagen is the requirement that they remove at least 85% of the offending Volkswagen cars from the road, through buyback offers; plus cash payments to owners. They estimate this will cost about $10 billion. Vehicles that they buy back will either get the software update and be resold, or be destroyed if they're not in resale condition. Here is where the settlement is at its most stupid. $10 billion is a lot of money. Applying this software update to Volkswagens will reduce their mileage by about 7%. They will burn more diesel for the same distance traveled, produce more CO2, and contribute more to global warming. I argue, and I think the science supports, that consumers and the environment would both have benefited more from leaving the cheat-mode cars on the road, and forcing Volkswagen instead to make that $10 billion a further investment in electric car technology.

The fundamental purpose of all the emissions laws that Volkswagen violated is to reduce emissions. However, a science-based analysis of how the lawmakers handled this reveals it to have been almost wholly counterproductive. The regulations already discourage nearly all manufacturers from selling diesels in the United States, when it's clear that modern filtered and catalyzed diesels are significantly better at emissions than gasoline alternatives. And when Volkswagen was caught and fined, the majority of the penalties will be wasted, squandering a once-in-a-century opportunity to make the single largest investment in electric cars — nearly triple the size of Tesla's investment in their Nevada Gigafactory. And, again, a large segment of the penalty will be spent to actually reduce the fuel efficiency and increase greenhouse emissions of hundreds of thousands of Volkswagens on the road. "Stupid on stilts", as we say.

Most of the criticism against Volkswagen was due to their emission of NOx, yet considering the far larger number of far dirtier diesels in Europe, the fact is that Volkswagen's contribution to the NOx problem and its associated health effects are a homeopathic drop in the bucket — yet they received an outrageously disproportionate punishment that did not address the more important problem. Folks, we need to get off fossil fuels. Forcing one of the cleanest diesel manufacturers to spend their money taking two steps backward was not the way to get there.

By Brian Dunning

Please contact us with any corrections or feedback.


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Cite this article:
Dunning, B. "Volkswagen Dieselgate Reexamined." Skeptoid Podcast. Skeptoid Media, 29 Aug 2017. Web. 22 Apr 2024. <>


References & Further Reading

Editors. "Soot and global warming." Skeptical Science. Skeptical Science, 18 Oct. 2011. Web. 13 Aug. 2017. <>

EPA. Volkswagen Clean Air Act Civil Settlement. Washington, DC: Environmental Protection Agency, 2017.

Hruska, J. "More manufacturers found to violate diesel emissions standards — but blame the test, not the vehicles." ExtremeTech. Ziff Davis LLC, 9 Oct. 2015. Web. 13 Aug. 2017. <>

Orlove, R. "Understanding The Test Mode That Let VW Trick The Emissions Test." Jalopnik. Gizmodo Media Group, 25 Sep. 2015. Web. 13 Aug. 2017. <>

Platt, S., El Haddad, I., Pieber, S., Zardini, A., Suarez-Bertoa, R., Clairotte, M., Daellenbach, K., Huang, R., Slowik, J., Hellebust, S., Temime-Roussel, B., Marchand, N., de Gouw, J., Jimenez, J., Hayes, P., Robinson, A., Baltensperger, U., Astorga, C. "Gasoline cars produce more carbonaceous particulate matter than modern filter-equipped diesel cars." Nature Scientific Reports. 13 Jul. 2017, Number 7.

Schindler, K. "Why Do We Need the Diesel?" SAE Technical Papers. 6 Aug. 1997, Number 972684.

Tisshaw, M. "Autocar test shows worse economy after Volkswagen diesel fix." Autocar. Haymarket Media Group, 17 May 2017. Web. 13 Aug. 2017. <>


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