Updated

President Barack Obama, seeking to end a stand-off between states and the auto industry, plans to issue new national emission limits and mileage requirements for cars and trucks. Obama plans to announce on Tuesday that he will couple pollution reduction from vehicle tailpipes with increased efficiency on the road. It would be the first time that limits on greenhouse gases were linked with federal standards for passenger cars and light trucks.

New vehicles would be 30 percent cleaner and more fuel efficient by 2016, according to officials familiar with the administration's discussions. The officials spoke on condition of anonymity because the formal announcement had not been made.

White House spokesman Robert Gibbs would not release details of the announcement on Monday, although he said the administration has been working with states, businesses and environmental groups on a deal.

California, 13 other states and the District of Columbia have urged the federal government to let them enact more stringent standards than the federal government's requirements. The states' regulations would cut greenhouse gas emissions by 30 percent in new cars and trucks by 2016 „ the benchmark Obama planned to unveil at the White House for vehicles built in model years 2011 and beyond.

The proposal is expected to coordinate two separate standards for fuel efficiency and greenhouse gas emissions from vehicles, aiming for cars that achieve higher miles per gallon and have lower polluting air conditioning systems, said Roland Hwang, the vehicles policy director for the Natural Resources Defense Council. The environmental group has discussed the upcoming changes with the White House in recent weeks, he said.

Hwang said he expected the greenhouse gas standard would be set to an equivalent of nearly 35 miles per gallon for the vehicle fleet by 2016.

A 2007 energy law requires car makers to meet at least 35 mpg by 2020, a 40 percent increase over the current standard of about 25 mpg. Passenger car requirements have remained unchanged at 27.5 mpg since 1985, drawing complaints from environmental groups that the government has been slow to push automakers to produce more fuel-efficient vehicles.

Obama's move also would effectively end litigation between states and automakers, who sought to block state-specific rules. The new federal rules would prompt automakers to drop their lawsuit. Two car companies who have been part of the litigation, General Motors Corp. and Chrysler LLC, have received billions in government loans during a dramatic downturn in car sales and weakened economy.

Auto industry executives, including GM CEO Fritz Henderson, were expected to participate in the announcement along with United Auto Workers President Ron Gettelfinger, industry officials said.

Michigan Gov. Jennifer Granholm, a Democrat who is being considered for the Supreme Court vacancy, will be at the White House for the event, said an administration official who spoke on condition of anonymity because details of the event had not been announced.

California Gov. Arnold Schwarzenegger, a Republican, will be in Washington for an announcement on California's request regarding federal auto emissions standards, spokesman Aaron McLear said. He declined to elaborate.

A March 2008 decision prevents states from setting their own limits on greenhouse gas emissions from automobiles, but Obama has ordered the U.S. Environmental Protection Agency to reconsider the ruling.

The EPA was already working toward establishing federal greenhouse gas emissions standards for new motor vehicles when it made a preliminary determination in April that six greenhouse gases „ four of which are released from automobiles „ endanger human health and welfare.

The White House announcement will make sure efforts by states, the EPA and the Transportation Department will occur in unison, said David Bookbinder, the Sierra Club's chief climate lawyer.

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