What does a yellow traffic signal indicate?

A yellow traffic signal indicates that the light is about to turn red. This warning is crucial for drivers to understand, as it serves as a cue to prepare to stop if it is safe to do so. The primary purpose of the yellow light is to provide drivers with a brief period to react, allowing them to either stop if they haven't entered the intersection or to proceed with caution if they are already committed to crossing. This transition from green to red is a fundamental aspect of the traffic signal system, aiming to enhance safety on the roads by minimizing the risk of collisions at intersections.