Washington Dulles International Airport passengers. Dulles was once assigned the airport code DIA, with each letter corresponding to the initials of Dulles International Airport. However, when handwritten, it was often misread as DCA, the code for nearby Ronald Reagan Washington National Airport. It was later revised to IAD to avoid confusion. The airport's terminal complex consists of a main terminal and two midfield terminal buildings: Concourses A/B and C/D. The entire terminal complex has 123 gates and 16 hardstand locations from which passengers can board or disembark using the airport's plane mate vehicles. Conceived in early planning sessions in 1959, Dulles is one of
Washington Dulles International Airport to a limited access highway, with the interchanges financed through a property tax surcharge on nearby business properties. The Dulles Toll Road has been extended to the west to Leesburg as the Dulles Greenway. Fairfax Connector routes 981 and 983 serve Dulles, connecting to the Herndon–Monroe park & ride lot in Herndon, the Reston Town Center transit in Reston, the Wiehle – Reston East Metro station, and the Steven F. Udvar-Hazy Center Air and Space Museum. The "Express" 5A Metrobus route operates service to the airport. The bus stops at the Herndon–Monroe park & ride lot in Herndon and the