D.C. Code § 50-1108
As used in this act, the term "motor vehicle" means all vehicles propelled by internal-combustion engines, electricity, or steam. The term "motor vehicle" shall not include traction engines, road rollers, vehicles propelled only upon rails or tracks, personal mobility devices, as the term is defined in section 2(13) of the District of Columbia Traffic Act, 1925, approved March 3, 1925 (43 Stat. 1119; D.C. Official Code § 50-2201.02(13) ), electric mobility devices, as the term is defined in section 2(6A) of the District of Columbia Traffic Act, 1925, approved March 3, 1925 (43 Stat. 1119; D.C. Official Code § 50-2201.02(6A) ), motorized bicycles, as the term is defined in section 2(11A) of the District of Columbia Traffic Act, 1925, approved March 3, 1925 (43 Stat. 1119; D.C. Official Code § 50-2201.02(11A) ), or a battery-operated wheelchair when operated by a person with a disability.
D.C. Code § 50-1108