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Unified Agenda 2060-AQ54

Joint Rulemaking To Establish 2017 and Later Model Year Light Duty Vehicle GHG Emissions and CAFE Standards


The Environmental Protection Agency (EPA) and the National Highway Traffic Safety Administration (NHTSA), on behalf of the Department of Transportation, have proposed a joint rulemaking on GHG and CAFE standards for model years 2017 to 2025 light-duty vehicles. This action represents a continuation of a coordinated National Program under the Clean Air Act (CAA) and the Energy Policy and Conservation Act (EPCA), as amended by the Energy Independence and Security Act (EISA), to improve fuel efficiency and to reduce greenhouse gas (GHG) emissions of light-duty vehicles. On July 29, 2011, President Obama announced a historic agreement with 13 automakers and the State of California to pursue 2017 to 2025 standards. This announcement was accompanied by a joint Supplemental Notice of Intent, issued by EPA and NHTSA, which outlined the standards and other key program elements the agencies intend to propose in the upcoming rulemaking. EPA and NHTSA intend to propose that automobile manufacturers meet a model year 2025 CO2 standard of 163 grams/mile, which is equivalent to 54.5 miles per gallon if the standard were achieved with fuel economy technologies alone. This latest notice followed a September 30, 2010, joint Notice of Intent that provided an initial assessment of potential levels of stringency for 2017 to 2025 standards, an Interim Joint Technical Assessment Report published jointly by EPA, NHTSA, and the California Resources Board in September 2010, and a November 30, 2010, Supplemental Notice summarizing key stakeholder comments.

Statement of need

EPA has found that emissions of greenhouse gases (GHGs) from new motor vehicles cause or contribute to pollution that may reasonably be anticipated to endanger public health and welfare. Light-duty vehicles emit four GHGs—carbon dioxide (CO2), methane (CH4), nitrous oxide (NOX), and hydrofluorocarbons (HFCs)–and are responsible for nearly 60 percent of all mobile-source GHGs. On May 21, 2010, the President called on the EPA and NHTSA, in close coordination with California, to begin the next phase of the National Clean Car Program and propose new standards for model years 2017 to 2025, in response to the urgent and closely intertwined challenges faced by our Nation of dependence on oil, energy security, and global climate change. This rulemaking would provide significant additional reductions in GHGs from future light-duty vehicles and fuel efficiency improvements.

Legal Basis

The Clean Air Act section 202(a)(1) states that "The Administrator shall by regulation prescribe (and from time to time revise) in accordance with the provisions of this section, standards applicable to the emissions of any air pollutant from any class or classes of new motor vehicles or new motor vehicle engines, which in his judgment cause, or contribute to, air pollution, which may reasonably be anticipated to endanger public health or welfare." Section 202(a) covers light-duty vehicles. In April 2007, the Supreme Court found in Massachusetts v. EPA that greenhouse gases fit well within the Act's capacious definition of "air pollutant" and that EPA has statutory authority to regulate emission of such gases from new motor vehicles. Lastly, in December 2009, EPA published two findings (74 FR 66496) that emissions of GHGs from new motor vehicles and motor vehicle engines contribute to air pollution, and that the air pollution may reasonably be anticipated to endanger public health and welfare.


The rulemaking proposal includes an evaluation of regulatory alternatives that can be considered in addition to the Agency's primary proposal. In addition, the proposal includes tools such as averaging, banking, and trading of emissions credits and other flexibilities for alternative approaches for compliance with the proposed program.

Costs and Benefits

The standards under consideration are projected to reduce GHGs by approximately 2 billion metric tons and save 4 billion barrels of oil over the lifetime of MY 2017 to 2025 vehicles. These standards would have significant benefits to American consumers by reducing the costs they would pay to fuel these more efficient vehicles.


The failure to set new GHG standards for light-duty vehicles would increase the risk of unacceptable climate change impacts.


5 actions from October 13th, 2010 to August 2012

  • October 13th, 2010
  • December 8th, 2010
  • August 9th, 2011
  • December 1st, 2011
  • August 2012
    • Final Action


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