UPPER MARLBORO, Md. — President Obama on Tuesday ordered the development of tough new fuel standards for the nation’s fleet of heavy-duty trucks as part of what aides say will be an increasingly muscular and unilateral campaign to tackle climate change through the use of the president’s executive power.

The new regulations, to be drafted by the Environmental Protection Agency and the Transportation Department by March 2015 and completed a year later so they are in place before Mr. Obama leaves office, are the latest in a series of actions intended to cut back on greenhouse gases without the sort of comprehensive legislation the president failed to push through Congress in his first term.

The limits on greenhouse gas pollution from trucks would combine with previous rules requiring passenger cars and light trucks to burn fuel more efficiently and pending rules to limit the carbon emissions of power plants. Cumulatively, experts said the à la carte approach should enable Mr. Obama to meet his target of cutting carbon pollution in the United States by 17 percent from 2005 levels by 2020. But they said he would still be far short of his goal of an 80 percent reduction by 2050.

“Improving gas mileage for these trucks is going to drive down our oil imports even further,” Mr. Obama said at a Safeway grocery distribution center here, flanked by a Peterbilt truck and Safeway and Coca-Cola cabs. “That reduces carbon pollution even more, cuts down on businesses’ fuel costs, which should pay off in lower prices for consumers. So it’s not just a win-win, it’s a win-win-win. We got three wins.”