|Fig. 1: Volkswagen's carbon emission rates.  (Source: Wikimedia Commons)|
The fear on Global Warming has placed a premium on finding solutions to mitigate the damage to the environment. Electric cars were an exciting movement towards the goal of decreasing the NO2 emission released from vehicles fuel by gasoline. The US Environmental Agency (EPA) has a mission to protect human and environmental health. The EPA alleged that Volkswagen Group of America (VW) violated the Clean Air Act (CAA) by developing and installing emissions control system 'defeat devices' (software) in model year 2009-2015 vehicles with diesel engines.  A group of researchers from West Virginia University were conducting tests on the exhaust fumes with the goal of proving the cleanliness of modern diesel engines. The results told the story of one of the boldest frauds in Corporate History. The effects of the decision to place the "defeat devices" in ~11 million cars had a direct impact on damage done to the environment. These devices reduced the usage of vehicle's exhaust filter and emission control system. 
The goal for Volkswagen was to overtake the American market but the emission regulations were much tighter than Europe. The U.S. Standards are strict on Nitrogen Oxides (NOx) and Particulate Matter (PM), while Europe is strict on Carbon Dioxide (CO2) and Carbon Monoxide (CO).  These differences show that European Regulators are focused on fuel efficiency with the goal of limiting dependency on crude oil from Russia and the Middle East. In addition, the tight regulation on Carbon Monoxide is to combat climate change. Fig. 1 shows Volkswagen's carbon emission rates from the past and projections of what it may look like in the years to come. American regulations are directly focused on smog and health impacts stemming from air pollution. 
Many engineers have discovered that adding a urea tank and an injection system will mitigate NOx emissions from diesel vehicles.  This system is not very efficient and wouldn't likely last anywhere near the life of the car. This is where Volkswagen decided to avoid the costs of this system with the ultimate goal of hitting price targets and maximizing the number of sales. However, in order to successfully pass the NO2 emissions test, they engineered a "defeat device" that served as exhaust control equipment in all the VW diesels that were programmed to shut off as soon as the cars rolled off the regulators' test beds, at which point the tail pipes released illegal levels of nitrogen oxides into the atmosphere, causing smog, respiratory diseases, and premature deaths.  The software was created to monitor steering movement while the engine ran. While the car was on the harness, the car wheels move but the steering wheel doesn't, unlike traditionally running, when they both work simultaneously when the car is in motion. By tracking this, the software could detect when the car was in test mode and therefore control the degree to which catalytic scrubbing was done on the emissions. This device officially fooled the system. 
The reported effects of the scandal include 45,093 tons of excess NOx emissions, 46.14 excess expected deaths, with $430 million in damages. U.S. authorities have extracted $25 billion in fines, penalties and restitution from VW for the 580,000 tainted diesels it sold in the U.S. In Europe, where the company sold 8 million tainted diesels, VW has not paid a single Euro in government penalties. The higher levels of nitrogen oxide caused diseases like emphysema and bronchitis. [5,6] The responsibility falls on the government to implement policy that will protect citizens and hold auto companies accountable to the environmental standards.
© K. J. Costello. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 M. R. Viola, D. B. Brown, and M. J. Paratore, Jr., "Method and Apparatus for Monitoring a Urea Injection System in an Exhaust Aftertreatment System," U.S. Patent 7610750, 3 Nov 09.
 G. Gates et al., "How Volkswagen's Defeat Devices Worked," New York Times. 16 March 17.
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 L. Hatton and M. von Genuchten, "When Software Crosses a Line," IEEE Software 33, 29 (2015).
 "Nitrogen Oxides (NOx), Why and How They are Controlled," U.S. Environmental Protection Agency, EPA 456F-99-006R, November 1999.
 M. Caballero, "Diesel Vehicles and the Volkswagen Emissions Scandal," Physics 240, Stanford University, Fall 2017.
 S. R. H. Barrett et al., "Impact of the Volkswagen Emissions Control Defeat Device on US Public Health," Environ. Res. Lett. 10, 114005 (2015).