What does a solid red traffic light signify?

A solid red traffic light signifies that all vehicles must come to a complete stop and wait for the light to change to green before proceeding. This is a critical traffic rule designed to ensure the safety of all road users. When faced with a solid red light, drivers must stop behind the stop line, crosswalk, or intersection, and are not allowed to continue moving forward until the light turns green. This regulation helps prevent accidents and ensures a clear flow of traffic.

In contrast, the other options suggest actions that are not permitted under a red light. Driving through with caution can lead to collisions, yielding to pedestrians is not relevant when the light is red for vehicles, and preparing to make a right turn often requires a specific condition such as a red light with a permissive sign or legal allowance, which does not occur under a solid red light without a specific exemption. Therefore, stopping and waiting for the light to turn green is not only the correct response but also essential for maintaining traffic safety.