D.C. Code § 9-602
It shall be the duty of the Mayor of the District of Columbia within the first 8 hours of daylight after the ceasing to fall of any snow or sleet, or after the accumulation of ice on the paved sidewalks within the fire limits of the District of Columbia, in front of or adjacent to all public buildings, public squares, reservations, and open spaces in the said District owned or held by lease by said District, to cause such snow, sleet, and ice to be removed; and also to cause the same to be removed from all crosswalks of improved streets and places of intersection of alleys with paved sidewalks, and also from all paved sidewalks or crosswalks used as public thoroughfares through all public squares, reservations, or open spaces within the fire limits of said District owned or held by lease by the District of Columbia; but in the event of inability to remove such accumulation of snow, sleet, and ice without injury to the sidewalk, by reason of the hardening thereof, it shall be his duty, within the first 8 hours of daylight after the hardening thereof, to make reasonably safe for travel, or cause to be made reasonably safe for travel, by the sprinkling of sand or ashes thereon, such paved sidewalks, crosswalks, and places of intersection of alleys with paved sidewalks, and shall, as soon thereafter as the weather shall permit, thoroughly clean, or cause to be thoroughly cleaned, said sidewalks, crosswalks, and places of intersection of alleys with paved sidewalks.
D.C. Code § 9-602
Section 14 of Pub. L. 93-140, § 14, 87 Stat. 507, effective Oct. 26, 1973, provided that, notwithstanding any other provision of law, appropriations for the Department of Transportation and the Department of Environmental Services of the government of the District of Columbia shall be available for purposes of snow and ice removal when so ordered by the Mayor of the District of Columbia. Section 14 of Pub. L. 93-140, § 14 was codified as § 9-607 in the 2001 Ed., as § 7-907 in the 1981 Ed., and as § 7-807 in the 1973 Ed. The Department of Transportation was substituted for Department of Highways and Traffic, near the beginning of this note, pursuant to Reorganization Plan No. 2 of 1975, dated July 24, 1975. The functions of the Department of Transportation were transferred to the Department of Public Works by Reorganization Plan No. 4 of 1983, effective March 1, 1984; the functions of the Department of Transportation were transferred to the Department of Public Works by Reorganization Plan No. 4 of 1983, effective March 1, 1984. This note originated at a time when local government powers were delegated to the District of Columbia Council and to a Commissioner of the District of Columbia; later abolished, these branches of government were replaced by the Council of the District of Columbia and the Office of Mayor of the District of Columbia, respectively. Accordingly, appropriate changes in terminology were made in this note.