One person was killed and at least 15 were injured after a tour bus overturned on the George Washington Parkway southeast of Washington D.C. on Tuesday afternoon, police said. The crash happened around 5:10 p.m. just north of the Mount Vernon Estate in Mt. Vernon, Va., law enforcement officials said. The accident involved a shuttle-sized tour bus and another vehicle, U.S. Park Police said. "The bus, carrying Chinese nationals, had 18 passengers plus the driver. The passenger car had two occupants," US Park Police said in a statement.