by Shruti Vaidyanathan, Senior Transportation Researcher

On September 18th, the Environmental Protection Agency (EPA) slapped the Volkswagen Group with a notice of violation (link is external) of the Clean Air Act for circumventing EPA emission standards for nitrogen oxides (NOx). Volkswagen has now acknowledged using so-called “defeat devices” on its diesel cars that turn on full emissions control technologies while in testing mode but allow the vehicles to emit nitrogen oxide levels up to 40 times the certified level during normal operation. In the United States,

Audi VW diesel
Audi Production in Foshan (China)
The Audi A3 Sportback* and the Audi A3 Sedan* (picture) have been driving off the assembly lines in Foshan since 2014.

Volkswagen will be forced to recall half a million vehicles. For that’s including the diesel versions of the popular Jetta. Also the Jetta Sportwagen, Beetle, Beetle Convertible, Golf, Golf Sportwagen, Passat, and Audi A3 models. That’s for model years 2009 to 2015.

In response to these events, has suspended Green Scores for the affected vehicles until further notice, since these scores are no longer reasonable estimations of the environmental impact of the Volkswagen diesels. Volkswagen’s diesel cars have performed well on ACEEE’s annual rankings since 2009, hovering just below our list of the top twelve “Greenest” vehicles with Green Scores in the high 40s. However, a 40-fold increase in on-road NOx would mean that these vehicles did not deserve those high Green Scores…


As of October 2015, Volkswagen had sold more than 11 million diesel cars worldwide. In addition. the scandal regarding Volkswagen’s use of software to cheat on U.S. emissions tests is a major issue. This has led to a “massive crisis” for the car company. The scandal is still unfolding, and it’s unclear how many vehicles have been affected by this scandal.
In the future, it’s possible that other automakers may be affected by this scandal. If you own a Volkswagen diesel car and you are concerned about this issue, you may want to make an appointment with your local dealership to discuss this with an employee.

To continue reading this blog post, visit:

ACEEE: The American Council for an Energy-Efficient Economy

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