The nation's first mandatory attempt to cut back on greenhouse gas emissions is now a fact—and it will show up in a driveway near you in 2012.

The new policy, aimed at combating climate change, will curb the greenhouse gases spewing from car and truck tailpipes. The U.S. Environmental Protection Agency (EPA) and Department of Transportation (DoT) released rules that set limits on the amount of greenhouse gas emissions allowed and accelerate an increase in overall fuel efficiency to 14.5 kilometers per liter (34.1 miles per gallon) by 2016. Cars and trucks on the road today get an average of roughly 10.6 kpl (25 mpg) and the new rules would cover roughly 60 percent of U.S. vehicles.

"These are the first regulations to cover greenhouse gases in the U.S., these for autos," EPA Administrator Lisa Jackson said during a press conference announcing the new rule. "The emission reductions from these changes will clean up the air we breathe, especially in urban areas…, [and] it is a victory for our planet and everyone who knows we must take action today and not push the challenge of climate change onto the next generation."

The new rules will be phased in starting in 2012 and require a roughly 5 percent cut in greenhouse gas emissions, along with a boost in fuel efficiency every year thereafter. By 2016, a manufacturer's full spread of vehicles for sale must emit an average of no more than 250 grams of carbon dioxide per mile (5.5. ounces per kilometer), down from an average of 400 grams per mile today. Ultimately, the EPA estimates that the rules will reduce CO2 emissions by nearly one billion metric tons, or roughly equivalent to taking 30 million cars and light trucks off the roads.

In addition, the new rules will save gas. The government agencies estimate that the program will save as much $190 billion in fuel costs and conserve roughly 1.8 billion barrels of oil. "Putting more fuel-efficient cars on the road isn't just a great way to save the environment. It's a great way for Americans to save money at the pump," said DoT administrator Ray LaHood at the press conference. "The price of gas isn't going to go down, it's going to go up."

Of course, that comes at a cost. The agencies estimate the rules will add roughly $950 to the price of a new car or truck in 2016 and cost industry $52 billion to implement. But Jackson notes that car buyers will save that much in fuel costs in three years, if they buy the vehicle outright.

In addition to improving the efficiency of gasoline-powered internal combustion engines through technologies such as direct injection, variable valve timing and turbocharging, the plan rests on giving a boost to electric-powered automobiles, such as the Nissan Leaf or Chevrolet Volt, according to officials at the DoT's National Highway Traffic Safety Administration. "Electric vehicles get counted as if they get zero emissions," Jackson noted. "We all know that's not entirely true because when you plug in there's emissions associated with the electricity you're using."

Nevertheless, greenhouse gas regulations for electricity-producing power plants will not come before 2011, Jackson said, but next year large power plants will be required to address greenhouse gas emissions in applying for permits. "Only a small number of sources will be immediately impacted," she added. "I don't have a date to announce for you [when those rules will be announced.] Certainly, it needs to come out as soon as possible."

Regardless, the Obama administration would prefer to see legislation to address climate change and energy from the U.S. Congress, rather than the EPA taking action. The House of Representatives has already passed a bill that would cut national greenhouse gas emissions by 4 percent below 1990 levels by 2020, whereas the Senate is currently drafting several competing bills. And the U.S. has signed on to the 2009 Copenhagen Accord, a nonbinding agreement to hold global warming below 2 degrees Celsius. The new regulations would cut greenhouse emissions by one billion metric tons over four years, but the U.S. emits roughly seven billion metric tons of greenhouse gases annually.

"This is a victory for drivers who, by 2016, will get 35 miles per gallon, spend less on fuel and send less of their dollars overseas," Jackson said, although the new rules still leave the U.S. behind Europe, Japan and China in terms of the timing or strength of fuel efficiency standards. Added LaHood: "All sales of automobiles are leading in the direction of more fuel-efficient autos."