DETROIT (AP) — Hours after being sworn in as the new U.S. Secretary of Transportation, Sean Duffy took aim at the main way the federal government regulates miles per gallon for cars and pickup trucks — also a principal way that it regulates air pollution and addresses climate change. Duffy ordered the federal agency in charge of fuel economy standards to reverse them as soon as possible. The standards have been in place since the 1970s energy crisis and were intended to conserve fuel and save consumers money at the gas pump.Here are five things to know about the action.What...