What is the main meaning of a red light at an intersection?

A red light at an intersection signifies that drivers must come to a complete stop before the stop line or crosswalk. This rule is crucial for ensuring the safety of all road users as it prevents collisions and allows pedestrians the opportunity to cross safely. When facing a red light, it is essential for drivers to take the action of stopping, which is legally mandated in order to regulate traffic flow and enhance safety at intersections.

While the other options provide important elements of driving behavior, they do not convey the direct and clear requirement of the light. For example, "proceed with caution" may suggest that drivers can move forward if they think it's safe, which contradicts the absolute need to stop at a red light. "Prepare to stop" is an important driving skill, but when the light is red, stopping is no longer a matter of preparation—it is an obligation. Similarly, yielding to pedestrians is important when they are present, but a red light itself requires a complete stop regardless of other conditions. Thus, the meaning of a red light is unequivocally to stop for safety and compliance with traffic laws.