The Washington Metropolitan Area Transit Authority manages the transport of the city. Residents carpool or vanpool to ease traffic, and also take the Metrorail and Metrobus to travel within Washington DC area. Even the disabled can take these modes of transit, as there are specially-made ramps and entrances for those with disabilities.
Stations can be easily found via placard names and rail line colors, or just look for the street level elevator locations and directions on pylons pointing customers to nearby entrances. International airports are also accessible via Metrobus and Metrorail, and you can even tour the Washington DC area easily though them.