National Environmental Policy Act
The National Environmental Policy Act (NEPA) requires that federal agencies disclose and evaluate the significant environmental impacts of proposed projects, and identify mitigation measures. This includes cumulatively significant impacts such as increased greenhouse gas emissions. The California Attorney General has filed comment letters under NEPA about proposed projects.
The Attorney General also filed a petition with the Ninth Circuit challenging the failure of the National Highway Traffic Safety Administration (NHTSA) to comply with NEPA when it issued new fuel economy standards for cars and trucks in 2005. The Ninth Circuit ruled in favor of the Attorney General in 2007. See Improved Fuel Economy Standards.