D.C. Mun. Regs. tit. 31, § 505
505.1 An independent taxicab, not affiliated with an association, company or fleet shall have its body, exclusive of metal trim, painted either black or white.
505.2 An independent taxicab may have a four-inch (4 in.) wide sapphire blue band extending along the side and across the rear of the vehicle at the bottom of the window openings. If the wheels are not completely covered by wheel covers, that part of each wheel as remains exposed may be painted sapphire blue.
505.3 An independent taxicab owner, prior to painting the taxicab, shall submit to the office an application for Commission approval listing the basic color together with all lettering, logo or insignia to be used.
505.4 Each independently operated taxicab shall have on the exterior of each rear door the name of the owner and a telephone number for contact purposes. The telephone number may be either a currently working home or cellular telephone number.
505.5 [Repealed]
505.6 The word "taxicab" shall be on each rear door under the name, trade name or insignia, unless the word "cab" is part of the trade name or insignia.
505.7 Each independently operated taxicab shall be assigned a number by the Office which shall be placed within a rectangle on each rear door, centered under the owner's name, trade name or insignia, and on the right of the rear of the vehicle so as to be clearly visible from the rear.
505.8 All letters and numbers on independently operated taxicabs shall be Gothic in style, three inches (3 in.) high with solid stroke width of three eighth inch (3/8 in.) stroke with three eighth of an inch (3/8 in.) between any digit and the inside edge as follows:
(a) On taxicabs with the body painted black, the numbers, letters and rectangles shall be white; or
(b) On taxicabs with the body painted white, the numbers, letters and rectangles shall be black;
SOURCE: Final Rulemaking published at 37 DCR 3595, 3599 (June 1, 1990); as amended by Final Rulemaking published at 40 DCR 4047, 4048 (June 25, 1993); and by Final Rulemaking published 45 DCR 8866, 8867 (December 11, 1998); as amended by Final Rulemaking published at 52 DCR 6678 (July 15, 2005); as amended by Final Rulemaking published at 53 DCR 853 (February 10, 2006).