BERKELEY, CA - FEBRUARY 18: Trucks drive along Interstate 80 on February 18, 2014 in Berkeley, California. U.S. President Barack Obama announced that his administration is beginning to develop a new phase of tighter fuel efficiency standards for medium and heavy-duty vehicles and has ordered the Environmental Protection Agency and Transportation Department's National Highway Traffic Safety Administration to create and impose new fuel-efficiency and greenhouse gas standards by March 31, 2016. (Photo by Justin Sullivan/Getty Images)
