The effect will be a new single national standard that will create a fleet of light-duty cars and trucks in the United States that will be nearly 40 percent cleaner and more fuel-efficient by 2016 compared to today, averaging 35.5 miles per gallon. Daniel Becker, director of the Safe Climate Campaign, which has been pushing for tougher mileage and emissions standards for two decades with the goal of curbing gases that have been linked to global warming. “This is the largest step the American government has ever taken to reduce greenhouse gases