In April 1924, the Arlington Memorial Bridge Commission proposed extending B Street all the way to the U.S. Capitol as part of the plan to turn the street into a major thoroughfare. The NCPC inspected B Street in June 1926, and in August made a preliminary determination that the street should be widened to between the Potomac River and Virginia Avenue NW. This would be accomplished by moving the south curb south by and the north curb north by . But once the street went past Virginia Avenue NW, the NCPC determined that the north curb should not be moved. In September 1926, the NCPC approved widening B Street to between 6th and 15th Streets NW (by moving the south curb south). This decision was reaffirmed by a joint meeting of the NCPC and the Office of the Supervising Architect of the U.S. Treasury (which was overseeing construction of the Federal Triangle office complex on the north side of B Street between 6th and 15th Streets NW). The NCPC agreed in February 1927 that B Street should extend to Pennsylvania Avenue NW, and was studying whether to extend it through the proposed Senate Park.