D.C. Mun. Regs. tit. 18, r. 18-2104
Whenever flashing red, yellow, or yellow arrow signals are used they shall require obedience by vehicular traffic as set forth in this section.
When a RED lens is illuminated with rapid intermittent flashes, drivers of vehicles shall stop before entering the nearest crosswalk at an intersection or at a limit line when marked, or, if none, then before entering the intersection, and the right to proceed shall be subject to the rules applicable after making a stop at a "STOP" sign.
When a YELLOW lens is illuminated with rapid intermittent flashes, drivers of vehicles may proceed through the intersection or past the signal only with caution.
When a YELLOW ARROW is illuminated with rapid intermittent flashes, vehicular traffic facing such indication may cautiously enter the intersection to make the movement indicated by such arrow, but shall yield the right-of-way to pedestrians within a crosswalk, and to any vehicle lawfully in the intersection or approaching on another highway so closely as to constitute an immediate hazard.
After a driver has yielded at a flashing yellow arrow in accordance with § 2104.4, the driver may proceed, and the drivers of all other vehicles approaching the intersection shall yield to the vehicle so proceeding; Provided, that if the driver is involved in a collision with a pedestrian in a crosswalk or a vehicle in the intersection after making the movement indicated by a flashing yellow arrow without stopping, such collision shall be deemed prima facie evidence of failure to yield right-of-way.
D.C. Mun. Regs. tit. 18, r. 18-2104