D.C. Mun. Regs. r. 18-731
No person shall drive any motor vehicle with any sign, poster, or other non-transparent material upon the front windshield, sidewings, or side or rear windows of the vehicle, except a sticker authorized by the Mayor, Public Service Commission, the Joint Board, or the Director.
The windshield on a motor vehicle shall be equipped with a mechanically operated device for cleaning rain, snow, or other moisture from the windshield. This device shall be constructed to be controlled by the driver of the vehicle.
No motor vehicle manufactured after January 1, 1938, shall be operated in the District unless the same is equipped with windshield wipers capable of wiping the right and left hand sides of the windshield.
Each windshield wiper shall be maintained in good working order.
No motor vehicle shall be operated when the windshield is cracked, scarred, clouded, or otherwise defective so as to obstruct vision.
Each motor vehicle shall be equipped with a mirror or mirrors so located as to reflect to the driver, under all conditions of loading, a view of the highway for a distance of at least two hundred feet (200 ft.) to the rear of the vehicle; Provided, that all vehicles licensed under the provisions of paragraph 31(b) and (c) of the Act of July 1, 1932, shall be equipped with two (2) adjustable rear-view mirrors installed to enable the driver to obtain a reasonably clear view toward the rear.
D.C. Mun. Regs. r. 18-731