What does a solid red traffic light mean?

A solid red traffic light indicates that drivers must come to a complete stop and remain stopped until the light changes to green. This signals to drivers that it is not safe to proceed through the intersection, as vehicles or pedestrians may be present. Stopping at a red light is a fundamental rule of road safety and traffic regulation.

In contrast, the other options suggest actions that do not align with the established traffic laws pertaining to a solid red light. For example, proceeding with caution implies that it is safe to move forward, which contradicts the urgent need to stop. Yielding to oncoming traffic does not apply when the light is red, as all vehicles must stop regardless of other traffic. Finally, turning left only does not make sense, as left turns on a red light are typically only permitted under specific conditions, such as when turning from a one-way street onto another one-way street, and not when facing a solid red light.