The pre-existing portions of the Silver Line opened as the Orange and Blue Lines on July 1, 1977, from to , on December 11, 1979 from Rosslyn to Ballston, November 22, 1980 from Stadium–Armory to , June 7, 1986 from Ballston-MU through and December 18, 2004 from Addison Road to . Unlike all prior segments of the Metrorail system, which were designed and constructed by the Washington Metropolitan Area Transit Authority (WMATA), the Silver line is designed and constructed by the Metropolitan Washington Airports Authority (MWAA) and operated by WMATA. The first phase of the project was funded 43% by $900 million of federal funding, 28% by a special tax district on commercial property proximate to the Silver Line route and 28% by a $0.50 toll increase on the Dulles Toll Road (State Route 267, SR 267). Funding for the second phase of the project is shared by Loudoun County, Fairfax County, the Commonwealth of Virginia and the MWAA.