daylight hours on Saturday and Sunday. Weekend-only operations ended on March 16, 1932. Though temporary lights were added in time for the 200th birthday, the highway wasn't opened for day and night use until both the bridge and highway were officially illuminated on May 6, 1932. The northern sections of the Parkway were mostly completed in the 1950s-1960s. The portion of the parkway from Glebe Road to I-495, was built primarily to provide access for workers at the new Central Intelligence Agency headquarters in Langley, Virginia, in 1959. The portion of the parkway just north of the Key Bridge was considered a model of modern highway design, and it was featured in many scholarly papers, engineering journals, and textbooks of the day. The Capper-Cramton Act received significant amendments in 1946, 1952, and 1958, both funding and terminating significant portions of the unbuilt parkway. The most significant changes came when Congress declined to fund construction of the segments from Fort Washington to the District of Columbia, from I-495 in Virginia to the Great Falls, and from MacArthur Boulevard/Carderock north to the Great Falls. Significant opposition to these segments emerged from the Izaak Walton League, the Wilderness Society, and other groups, which argued that the environmental damage caused by these segments would be too severe to justify their construction. Over time, small additions were made to the parks and roads included in the larger areas administered by the George Washington Memorial Parkway. These included Memorial Drive (the short section of roadway from the Arlington Memorial Bridge to the entrance of Arlington National Cemetery, at Theodore Roosevelt Island (added in 1933), and the LBJ Memorial Grove on Columbia Island in 1974. Administrative history The parkway was authorized May 29, 1930, and transferred from the Office of Public Buildings and Public Parks of the National Capital on August 10, 1933. On November 28, 1989, the portion in Maryland was renamed the Clara Barton Parkway. The parkway also administers other National Park Service features and areas in the vicinity. Parkway sites include: Arlington House, The Robert E. Lee Memorial Arlington Memorial Bridge & Avenue Arlington Ridge Park Belle Haven Park & Marina Clara Barton National Historic Site Clara Barton Parkway Claude Moore Colonial Farm Collingwood Picnic Area Columbia Island Marina Daingerfield Island Dyke Marsh Wildlife Preserve Fort Hunt Park Fort Marcy Park Glen Echo Park Gravelly Point Great Falls Park Jones Point Park & Lighthouse