Final answer:
Flashing red lights on a school bus signal that it is stopped and students are either getting on or off, requiring nearby drivers to stop.
Step-by-step explanation:
Flashing red lights tell the driver that the school bus is stopped and is loading or unloading students. When you see a school bus with flashing red lights, it is a signal indicating that all drivers in both directions must come to a full stop, allowing students to safely enter or exit the bus. This traffic rule aligns with a broader understanding of traffic signals where a steady red light requires all vehicles to stop, ensuring pedestrian safety and orderly flow of traffic.