The Washington Metropolitan Area is often cited as having some of the nation's worst traffic and congestion. In 2007, Washington commuters spent 60 hours a year in traffic delays, which tied for having the worst traffic in the country after Los Angeles. However, 37.7% of Washington commuters take public transportation to work, also the second-highest rate in the country.
The Washington Metropolitan Area Transit Authority (WMATA) operates the city's rapid transit system, Metrorail (most often referred to as the Metro), as well as Metrobus. The subway and bus systems serve both the District of Columbia and the immediate Maryland and Virginia suburbs. Metrorail opened on March 27, 1976 and presently consists of 86 stations and 106.3 miles (171.1 km) of track. With an average of one million trips each weekday in 2009, Metrorail is the nation's second-busiest rapid transit system in the country, after the New York City Subway.
WMATA expects an average one million Metrorail riders daily by 2030. The need to increase capacity has renewed plans to add 220 subway cars to the system and reroute trains to alleviate congestion at the busiest stations. Population growth in the region has revived efforts to construct two additional suburban Metro lines, as well as a new streetcar system to interconnect the city's neighborhoods. The DC Circulator bus system connects commercial and entrainment areas within central Washington. Metrorail, Metrobus and all local public bus systems in the metropolitan area accept SmarTrip, a reloadable transit pass.

Interior of terminals B and C at Reagan National Airport, the closest commercial airport to downtown Washington
Union Station is the second-busiest train station in the United States, after Penn Station in New York, and serves as the southern terminus of Amtrak's Northeast Corridor and Acela Express service. Maryland's MARC and Virginia's VRE commuter trains and the Metrorail Red Line also provide service into Union Station. Intercity bus service is provided by Greyhound, Peter Pan, BoltBus, Megabus, and many other Chinatown bus lines.
Three major airports, one in Maryland and two in Virginia, serve Washington, D.C. Ronald Reagan Washington National Airport, located just across the Potomac River from downtown D.C. in Arlington County, Virginia, is the only Washington-area airport that has its own Metrorail station. Given its proximity to the city, Reagan National has extra security precautions required by the Washington Air Defense Identification Zone, as well as additional noise restrictions. Reagan National does not have U.S. Customs and Border Protection and therefore can only provide international service to airports that permit United States border preclearance, which includes destinations in Canada and the Caribbean.
Major international flights arrive and depart from Washington Dulles International Airport, located 26.3 miles (42.3 km) west of the District in Fairfax and Loudoun counties in Virginia. Baltimore-Washington International Thurgood Marshall Airport is located 31.7 miles (51.0 km) northeast of the District in Anne Arundel County, Maryland.