Final answer:
When the yellow lights are flashing, drivers must slow down to the posted speed limit of 20 mph in a school zone for the safety of students and other pedestrians.
Step-by-step explanation:
When the yellow lights are flashing, all drivers approaching a school zone must obey the posted speed limit of 20 mph. The yellow flashing lights serve as a warning to drivers that they are entering an area where children are likely to be present, and therefore, they need to exercise caution and slow down. It is not only a legal requirement to observe this speed limit, but it is also a critical measure to ensure the safety of young pedestrians who may be coming to or leaving school.
Flashing yellow lights in other contexts, such as a construction zone or a railroad crossing, typically indicate the need for caution as well. However, these scenarios often have different rules and speed limits attached. In the case of a school zone, the goal of the reduced speed limit, coupled with the flashing yellow lights, is to prevent accidents and improve pedestrian safety, as students and others navigate traffic when arriving at or departing from the campus.