Section 21-204 - Flashing signals(a) If a flashing red or yellow light is used in a traffic signal or with a traffic sign, it requires obedience by vehicular traffic as provided in this section.(b) If a red lens is lit with rapid intermittent flashes, the driver of a vehicle shall stop at the near side of the intersection at a clearly marked stop line.(c) If a red lens is lit with rapid intermittent flashes, the driver of a vehicle shall stop at the near side of the intersection, if there is no clearly marked stop line, before entering any crosswalk.(d) If a red lens is lit with rapid intermittent flashes, the driver of a vehicle shall stop at the near side of the intersection, if there is no crosswalk, before entering the intersection.(e) The right to proceed after making the stop is subject to the rules applicable after making a stop at a stop sign.(f) If a yellow lens is lit with rapid intermittent flashes, the driver of a vehicle may proceed through the intersection or past the signal only with caution.(g) This section does not apply at any railroad grade crossing.