First responders aid injured people at the finish line of the Boston Marathon after the bombing on April 15. Charles Krupa/AP hide caption

itoggle caption Charles Krupa/AP

A sign on I-93 alerts motorists that Boston is under a "shelter in place" order Friday. Elise Amendola/AP hide caption

itoggle caption Elise Amendola/AP

Drivers travel on Interstate 495, the Capital Beltway, near Tysons Corner in Fairfax County, Va., in November, just days before the opening of four new express lanes. Virginia is among 19 states that have approved or are considering legislation to increase transportation funding, according to Transportation for America. Cliff Owen/AP hide caption

itoggle caption Cliff Owen/AP

The Federal Bureau of Investigation headquarters in Washington, just blocks from the White House, has long been the government building everyone loves to hate. Manuel Balce Ceneta/AP hide caption

itoggle caption Manuel Balce Ceneta/AP

The 63-year-old Frederick Douglass Memorial Bridge in Washington, D.C., has been labeled structurally deficient — as is 1 in 9 bridges in America. Rod Lamkey Jr./The Washington Times/Landov hide caption

itoggle caption Rod Lamkey Jr./The Washington Times/Landov

A statue of golf legend Arnold Palmer stands outside Arnold Palmer Regional Airport in Latrobe, Pa. Brian Naylor /NPR hide caption

itoggle caption Brian Naylor /NPR

The Bureau of Alcohol, Tobacco, Firearms and Explosives has not had a permanent administrator since Congress required that the director be confirmed by the Senate in 2006. AFP/AFP/Getty Images hide caption

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A passenger jet flies past the FAA control tower at Washington's Ronald Reagan National Airport in 2011. Cliff Owen/AP hide caption

itoggle caption Cliff Owen/AP

U.S. Treasury checks are run through a printer. William Thomas Cain/Getty Images hide caption

itoggle caption William Thomas Cain/Getty Images