D.C. Code § 9-1205.03

Subject only to the approval of the Mayor of the District of Columbia the crossing of any public street or alley other than New York Avenue, within the limits of the total area noted in § 9-1205.01 may be at or on grade. The said railroad shall, when and as directed by the Mayor of the District of Columbia, construct at its entire cost and expense, an additional overhead bridge for the track hereby authorized to be established over such other street located between Montello Avenue and New York Avenue as such street may now or may hereafter be shown on the Plan of the Permanent System of Highways.