washington u.s. environmental protection agency chief gina mccarthy friday finalize determination landmark fuel efficiency rule institute president barack obama lock 2025 bid maintain key part administration climate legacy major u.s. foreign automakers appeal president-elect donald trump critical obama climate policies review rule require nearly double fleet-wide fuel efficiency 2025 say impose significant cost step consumer preferences part 2012 regulation epa decide april 2018 whether modify 2022-2025 model year vehicle emission rule require average fleet-wide efficiency 50 miles per gallon november agency move timetable propose automakers meet 2025 standards mccarthy say statement determination legally bind decision maintain fuel efficiency rule rest extensive technical record mccarthy say determination rule feasible practical appropriate best interest auto industry tell automakers epa could consider adopt new rule provide additional incentives clean technologies flexibilities could assist manufacturers long term plan 2011 obama announce agreement major automakers raise fuel efficiency standards 54.5 miles per gallon administration say would save motorists 1.7 trillion fuel cost life vehicles cost auto industry 200 billion 13 years july epa say americans buy few cars suvs truck estimate fleet average 50.8 mpg 52.6 mpg 2025. gloria bergquist spokeswoman alliance automobile manufacturers trade association represent general motor co ford motor co toyota motor corp volkswagen ag vowg_p.de others criticize decision fundamental priority remain strike right balance continue fuel economy gain carbon reduction without compromise consumer affordability vital auto-sector job say automakers hope work regulators california bergquist say see whether find prudent compromise path forward avoid unnecessary counterproductive regulatory collision environmental group praise decision ken kimmell president union concern scientists say standards work automakers technologies continue progress cost-effective way keep us track reduce oil use 2.4 million barrel day cut global warm emissions keep american-made vehicles competitive rapidly-changing global market say legal experts say difficult trump administration congress undo determination unwind regulatory action issue obama administration final months office 2025 determination new regulation epa trump would likely go extensive process withdraw determination could face lawsuits environmental group take step sierra club executive director michael brune say statement new administration reason shift progress reverse epa lock 2025 fuel efficiency rule