What does a red traffic light signify?

A red traffic light signifies that drivers must stop and wait for the green light before proceeding. This rule is fundamental to ensuring road safety and preventing accidents at intersections. When the light is red, it indicates that vehicles must come to a complete halt at the designated stop line or before entering the intersection. This is crucial for managing traffic flow and protecting pedestrians who may be crossing the road.

In this context, the other options indicate actions that are not appropriate when a red light is displayed. Proceeding with caution is not advisable because it may lead to running the red light and causing a collision. Slowing down and looking might imply a lack of necessity to stop, which is incorrect as all vehicles must halt. Yielding to pedestrians is an important traffic rule, but it applies in specific scenarios, such as at crosswalks when the light is green for pedestrians. However, when a red light is present, the primary action required is to stop.