§ 70.34 FLASHING SIGNALS.
   Whenever an illuminated flashing red or yellow signal is used in conjunction with a traffic-control device, it shall require obedience by vehicular traffic as follows:
   (A)   Flashing red (stop signal). When a red lens is illuminated with rapid intermittent flashes, drivers of vehicles shall stop at a clearly marked stop line, but if none, before entering the crosswalk on the near side of the intersection, or if none, then at a point nearest the intersecting roadway where the driver has a view of approaching traffic on the intersecting roadway before entering the intersection, and the right to proceed shall be subject to the rules applicable after making a stop at a stop sign.
   (B)   Flashing yellow (caution signal). 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.
   (C)   This section does not apply at railroad grade crossings.
(625 ILCS 5/11-309) Penalty, see § 70.99