D.C. Mun. Regs. tit. 18, § 2214
2214.1 No person shall board or alight from a vehicle while the vehicle is in motion.
2214.2 No driver shall permit any person to board or alight from the vehicle he or she is driving while the vehicle is in motion.
2214.3 No motor vehicle shall be operated with any front door(s), sidedoor(s), or rear door(s) tied open or swinging.
2214.4 No person shall open any door of a vehicle unless it is reasonably safe to do so and can be done without interfering with moving traffic or pedestrians and with safety to such person and passengers. No person shall leave a door open on a side of a vehicle available to moving traffic for a period of time longer than necessary to receive or discharge passengers.
SOURCE: Commissioners' Order 274, 310/949, effective September 1, 1949; 17 DCRR §§ 71-75 (October 19, 1970); as amended by the Bicyclist Responsibility Regulation Amendment Act of 1996, effective April 9, 1997 (D.C. Law 11-178; 43 DCR 4240 (August 9, 1996)).