What does a solid red traffic signal indicate?

A solid red traffic signal indicates that drivers must come to a complete stop and must not proceed until the light turns green. This rule is crucial for maintaining traffic safety and ensuring that all vehicles adhere to the same traffic control measures. The purpose of the red light is to manage the flow of traffic and prevent collisions at intersections by clearly indicating when it is unsafe for vehicles to move.

In contrast, the other responses do not adhere to the clear directive of a solid red light. For instance, slowing down and proceeding with caution, yielding to incoming traffic, or preparing to stop are not appropriate actions when a solid red signal is present, as they could lead to confusion and potentially dangerous situations. Thus, it is essential for drivers to understand that the fundamental meaning of a solid red light is to stop completely until they receive the signal to proceed.