EPA’s Rigorous Auto Oversight Will Get Even Stronger

By Christopher Grundler, Director, Office of Transportation and Air Quality

Last month, Volkswagen admitted to EPA and the California Air Resources Board that the company employed a sophisticated device to cheat U.S. emissions standards in certain diesel cars, including the Audi A3, Beetle, Golf, Jetta, and Passat. We take this matter very seriously. It’s not only a violation of the Clean Air Act, it threatens public health and the credibility of the industry.

Our goal is to complete a comprehensive investigation and to take the appropriate steps to ensure that this never happens again. We are now testing for defeat devices and other compliance issues for model year 2015 and 2016 light-duty diesel vehicles from all manufacturers. On September 25, we notified all auto manufacturers that our testing will include additional evaluations designed to detect potential defeat devices.

We employ a rigorous, multi-layer process to test and certify new vehicle models before they can be sold, and for testing vehicles that are in production and on the road. But technologies evolve and circumstances change, and we’re constantly looking at ways to improve our compliance and oversight programs. Over the past 45 years, our oversight and testing program has developed new tools and new techniques to adapt to technology advances so we can deliver on the agency’s mission.

In the late 1990’s, the heavy-duty industry deployed defeat devices in a large number of trucks, resulting in a settlement valued at over $1 billion. We’ve done extensive on-road testing audits for compliance with the newly implemented greenhouse gas emissions standards. This effort resulted in an enforcement action and ultimately a record-setting settlement with Hyundai/Kia, and significant fuel economy adjustments by Ford and other vehicle manufacturers.

Our testing and oversight includes both in-lab testing using dynamometers and on-road testing in real-world conditions. Both are necessary as part of an active robust program. This provides a multi-layered oversight approach focused on:

  • Testing both pre-production prototypes and production vehicles on the dynamometer, which provides accurate, reliable and repeatable measurements that can be used to compare against the standard, and across vehicle types;
  • On-road testing using portable emissions monitors (PEMs) that measure emissions during real world driving situations. In recent years, on-road PEMs testing has been focused on heavy duty diesel vehicles, which account for roughly 40 percent of the NOx pollution from on-road sources.  (By comparison light duty diesel cars account for about 0.1 percent of NOx pollution from on-road sources.)
  • Laboratory audits ensuring that manufacturer, contract, and other agency test labs conform to testing protocols and data quality standards, so that the data EPA gets from these sources (including the data manufacturers provide to EPA) meet standards and that results can be compared among labs; and
  • Holding manufacturers accountable for their actions through rigorous enforcement of the Clean Air Act, which provides a strong deterrence against cheating and helps maintain a level playing field for the vast majority of automakers that play by the rules.

Air quality monitors across the country tell a clear and compelling story: U.S. air quality has dramatically improved as a result of implementing our programs as vehicle miles and the economy have grown significantly. Since EPA’s founding, we’ve cut our nation’s air pollution 70% all while the economy has tripled. A strong oversight and compliance program is critical to ensure that the clean air standards that EPA sets for vehicles to protect public health actually deliver the emissions promised to the American people.  We will learn from this Volkswagen case, and will adapt and improve — as we have before — to ensure we deliver on the Agency’s mission.

More information for owners of affected vehicles may be found here:

Editor's Note: The views expressed here are intended to explain EPA policy. They do not change anyone's rights or obligations.

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Climate for Action: Reducing your Carbon Footprint on the Road

About the Author: Loreal Crumbley, a senior at George Mason University, is an intern with EPA’s Environmental Education Division through EPA’s Student Temporary Employment Program (STEP).

There are many ways to reduce your personal impact on climate change. An easy way to decrease your contribution is by reducing your transportation emissions. When we drive we release carbon dioxide into the atmosphere. There are many different steps you can take to help reduce greenhouse gas emissions and to save money!

There are plenty of alternatives to driving our personal vehicles. We can join carpools, which help save energy and produce fewer emissions. My county offers special carpool parking lots and designated highway routes for carpoolers. If you research carpooling in your area, you may find that your county provides benefits for carpool riders. Instead of driving a car you can walk or bike ride to school and work. Since summer is starting, walking or riding a bike also makes it easy to spend more time outside rather than cooped up in your car.

Another way to lessen your impact is to keep your vehicle well serviced. If you keep your car well tuned and follow the manufacturer’s guide to scheduled maintenance, you will produce fewer emissions. Not only will you reduce greenhouse gas emissions but you will have a more fuel-efficient car and it will be more reliable. You should also change air filters regularly and use the recommended motor oil. Having a well tuned engine can reduce fuel consumption. Regularly checking the amount of air in your tires can also decrease your fuel consumption, and the less fuel your vehicle consumes, the less it pollutes the air and the fewer greenhouse gases it emits.

Here are a few tips to becoming an environmental driver:

  • Avoid idling for long periods of time.
  • Turn off engine when sitting or waiting.
  • Reduce weight in your trunk and unload unnecessary items.
  • Be easy on brakes and gas pedal;, driving at moderate speeds uses less fuel.
  • Try smoother accelerations. They pollute less and save fuel.
  • Plan your trips and combine errands to reduce mileage.

For more information on climate change and what you can do while on the road, please visit:

We can all do our part to help reduce climate change. Remember it’s never too late to start new habits! If you haven’t started driving yet, these tips could be helpful for your parents or friends who have their licenses. Spread the word. We all need to work together in this fight to reduce climate change!

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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