D.C. Mun. Regs. tit. 18, r. 18-2213
No person shall drive a vehicle when it is so loaded as to obstruct the view of the driver to the front or sides of the vehicle or when it is so loaded as to interfere with the driver's control over the driving mechanism of the vehicle.
No person shall drive a vehicle with more than three (3) persons in the front seat when such occupancy obstructs the view of the driver to the front or sides of the vehicle or interferes with the driver's control over the driving mechanism of the vehicle.
No passenger in a vehicle or streetcar shall ride in such position as to interfere with the driver's or operator's view ahead or to the sides, or to interfere with control over the driving mechanism of the vehicle or streetcar.
An operator shall, when operating a vehicle, give full time and attention to the operation of the vehicle.
No driver of any motor vehicle in motion shall permit any person or persons to stand on the running board and no person shall ride on the running board when the vehicle is in motion.
No person shall ride on any portion of any vehicle which is not designed or intended for the use of passengers, and no driver of a vehicle shall permit such riding. This provision shall not apply to an employee engaged in the necessary discharge of his or her duty or to persons riding within truck bodies in space intended for materials.
No vehicle operated on the highways of the District shall have any object attached to or suspended from the rear view mirror or rear view mirror bracket; or have any object attached to or suspended from the windshield, the rear window, the front side windows, or the frame of the windshield, rear window, or any front side window.
Subsection 2213.7 shall not be construed to prohibit the hanging of clothing or other objects from a hanger attached to either of the rearside windows of a vehicle, nor shall it be construed to prohibit the display of a sticker authorized or required to be displayed by the Joint Board, Council, Mayor, Director, or Public Service Commission.
D.C. Mun. Regs. tit. 18, r. 18-2213