With a map of the United States on a truck in the background, President Barack Obama speaks about how having a fuel-efficient truck fleet can boost the economy and help combat climate change, Tuesday, Feb. 18, 2014, at the Safeway Distribution Center in Upper Marlboro, Md. (AP Photo/Jacquelyn Martin)

Photo by: Jacquelyn Martin

With a map of the United States on a truck in the background, President Barack Obama speaks about how having a fuel-efficient truck fleet can boost the economy and help combat climate change, Tuesday, Feb. 18, 2014, at the Safeway Distribution Center in Upper Marlboro, Md. (AP Photo/Jacquelyn Martin)