By Sept. 28, 2011, EPA and the US Dept. of Transportation's National Highway Traffic Safety Administration (NHTSA) say they will jointly release proposed standards designed to significantly increase fuel mileage and reduce greenhouse gas emissions from passenger cars, light trucks, and medium-duty passenger vehicles in model years 2017-2025. The standards are being coordinated with the state of California. A final rule is scheduled to be issued by July 31, 2012.
- Supplemental Notice of Intent, Summary, July 29, 2011. 
- Supplemental Notice of Intent, Federal Register, Aug. 9, 2011. 
- EPA: Transportation and Climate, Regulations and Standards. 
- NHTSA: CAFE — Fuel Economy. 
The new standards are expected to build on efforts made to develop similar standards for model years 2012-2016, finalized May 7, 2010.
- Final Rulemaking: Light-Duty Vehicle Greenhouse Gas Emissions Standards and Corporate Average Fuel Economy Standards. 
In light of President Obama's recent decision to stop development of another major EPA regulation — setting a more stringent standard for ground-level ozone — it remains uncertain whether the vehicle regulations will proceed on schedule. However, some observers say this regulation might advance because the vehicle industry generally supports it. Among those who are currently saying they will be cooperative are BMW, Chrysler, Ford, GM, Honda, Hyundai, Nissan, and Toyota. For their letters of qualified support, and those of others, including the California Air Resources Board, see:
- Transportation and Climate; Regulations and Standards, Light Duty Regulations, Commitment Letters. 
Among other sources for possible comment are:
- International Union, United Automobile, Aerospace and Agricultural Implement Workers of America (UAW), press release, July 29, 2011. 
- Natural Resources Defense Council: Grasping Green Car Technology ; July 28, 2011, press release. 
- Sierra Club: Green Cars, Fuels, and Transportation for the 21st Century ; press release, July 29, 2011. 
- National Wildlife Federation: Promoting Clean Transportation ; press release, July 28, 2011.