WASHINGTON - Drivers will have to pay more for cars and trucks, but they'll save at the pump under tough new federal rules aimed at boosting mileage, cutting emissions and hastening the next generation of fuel-stingy hybrids and electric cars.

The new standards, announced Thursday, call for a 35.5 miles-per-gallon average within six years, up nearly 10 mpg from now.

By setting national standards for fuel efficiency and greenhouse gas emissions from tailpipes, the government hopes to squeeze out more miles per gallon whether you buy a tiny Smart fortwo micro car, a rugged Dodge Ram pickup truck or something in between.

The rules will cost consumers an estimated $434 extra per vehicle in the 2012 model year and $926 per vehicle by 2016, the government said. But the heads of the Transportation Department and Environmental Protection Agency said car owners would save more than $3,000 over the lives of their vehicles through better gas mileage.

Touting the plan, Transportation Secretary Ray LaHood said, "Putting more fuel-efficient cars on the road isn't just the right thing to do for our environment, it's also a great way for Americans to save a lot of money at the pump."

The requirements for the 2012-2016 model years pleased environmentalists who have criticized sluggish efforts by previous administrations to boost fuel efficiency. They also were welcomed by automakers who have been seeking a single standard after California and a dozen states tried to create their own rules.

Dave McCurdy, a former Oklahoma congressman who leads the Alliance of Automobile Manufacturers, a trade group representing 11 automakers, said the industry supported the single national standard for future vehicles. He said the program made "sense for consumers, for government policymakers and for automakers."

Not all dealers were pleased. Ed Tonkin, a Portland, Ore., car dealer who chairs the National Automobile Dealers Association, said the rules were the "most expensive fuel economy mandates in history" and would turn many new cars and trucks into luxury items for consumers.

"Under these new mandates, the price of new cars and light trucks will rise significantly, meaning fewer Americans will be able to buy the new vehicles of their choice," Tonkin said.

Environmental groups said the changes would actually give consumers more choices because they ensure that every new car would get slightly more fuel-efficient each year.

"Because of these standards, Americans will drive vehicles that save them money at the pump, cut the country's oil dependence and produce a lot less global warming pollution," said Jim Kliesch, a senior engineer in the Union of Concerned Scientists' Clean Vehicles Program.

The regulations set a goal of achieving by 2016 the equivalent of 35.5 miles per gallon combined for cars and trucks, an increase of nearly 10 mpg over current standards set by the National Highway Traffic Safety Administration. The figure could actually be as low as 34.1 mpg because automakers can receive credits for reducing greenhouse gas emissions in other ways, including preventing the leaking of coolant from air conditioners.

The changes will cost the auto industry about $52 billion, but the government says the program will provide $240 billion in savings to consumers, mostly through lower fuel consumption. The changes also could help U.S. manufacturers who produce advanced vehicles, batteries and engines, the government said.

The EPA is setting a tailpipe emissions standard of 250 grams of carbon dioxide per mile for vehicles sold in 2016, equal to what would be emitted by vehicles meeting the mileage standard. This represents the EPA's first rules ever on vehicle greenhouse gas emissions, following a 2007 Supreme Court decision.