The Mayor of the District of Columbia is hereby authorized and directed to prepare a plan for the extension of a permanent system of highways over all that portion of said District not included within the limits of the Cities of Washington and Georgetown. Said system shall be made as nearly in conformity with the street plan of the City of Washington as the Council of the District of Columbia may deem advisable and practicable. The highways provided in such plans shall not in any case be less than 90 feet nor more than 160 feet wide, except in cases of existing highways, which may be established of any width not less than their existing width and not more than 160 feet in width.

The said plans shall be prepared from time to time in sections, each of which shall cover such an area as the Mayor of the District of Columbia may deem advisable to include therein, and it shall be the duty of the Mayor in preparing such plan by sections, as far as may be practicable, to select first such areas as are covered by existing suburban subdivisions not in conformity with the general plan of the City of Washington. The Mayor in making such plans shall adopt and conform to any then existing subdivisions which shall have been made in compliance with the provisions of the Act of Congress approved August 27, 1888, entitled "An act to regulate the subdivision of land within the District of Columbia" (25 Stat. 451), or which shall, in the opinion of the Mayor, conform to the general plan of the City of Washington; provided, however, that no place or street extending no farther than from 1 principal street to another, which has been opened under the direction of the Mayor, or in conformity with any subdivision approved by them prior to August 27, 1888, and recorded, and which was on March 2, 1893, paved with asphalt or other sheet pavement, shall be altered, affected, or interfered with by any plan adopted or anything done under or by virtue of §§ 9-103.01 to 9-103.05. Whenever the plan of any such section shall have been adopted by the Mayor, he shall cause a map of the same to be made showing the boundaries and dimensions of and number of square feet in the streets, avenues, and roads established by him therein; the boundaries and dimensions of and number of square feet in each, if any, of the then existing highway in the area covered by such map, and the boundaries and dimensions of and number of square feet in each lot of any then existing subdivision owned by private persons; and containing such explanations as shall be necessary to a complete understanding of such map. In making such maps the Mayor is further authorized to lay out at the intersections of the principal avenues and streets thereof circles or other reservations corresponding in number and dimensions with those existing on March 2, 1893, at such intersections in the City of Washington. A copy of such map, duly certified by the Mayor, shall be delivered to the National Capital Planning Commission, which shall make such alterations, if any, therein, as it shall deem advisable, keeping in view the intention and provisions of §§ 9- 103.01 to 9-103.05, and the necessity of harmonizing as far as possible the public convenience with economy of expenditure; and if such Commission shall see fit, it may cause to be made a new map in place of the one submitted to them. When such Commission, or a majority thereof, shall have come to a final determination in the matter, it shall approve in writing the map which it shall adopt, and shall deliver it to said Mayor of the District of Columbia, and the same shall at once be filed and recorded in the Office of the Surveyor of the District of Columbia, and after any such map shall have been so recorded no further subdivision of any land included therein shall be admitted to record in the Office of the Surveyor of said District, or in the Office of the Recorder of Deeds thereof, unless the same be first approved by the Mayor and be in conformity to such map. Nor shall it be lawful when any such map shall have been so recorded for the Mayor of the District of Columbia, or any other officer or person representing the United States or the District of Columbia, to thereafter improve, repair, or assume any responsibility in regard to any abandoned highway within the area covered by such map, or to accept, improve, repair, or assume any responsibility in regard to any highway that any owner of land in such area shall thereafter attempt to lay out or establish, unless such landowner shall first have submitted to the Mayor a plat of such proposed highway and the Mayor shall have found the same to be in conformity to such map, and shall have approved such plat and caused it to be recorded in the Office of said Surveyor.

When any such map shall have been recorded as aforesaid in the Office of the Surveyor of the District it shall be lawful for the owner of any land included within such map to adopt the subdivision thereby made by a reference thereto and to this section in any deed or will which he shall thereafter make, and when any deed or will containing any such reference shall have been made and recorded in the proper office it shall have the same effect as though the grantor or grantors in such deed or the maker of such will had made such subdivision and recorded the same in compliance with law.

For the purpose of making surveys for such plans and maps the Mayor of the District of Columbia and his agents and employees necessarily engaged in making such surveys are authorized to enter upon any lands through or on which any projected highway or reservation may run or lie.

None of the provisions of §§ 9-103.01 to 9-103.05 shall apply to any segment of the Interstate System within the District of Columbia.