Which color of traffic light indicates that drivers must stop?

The color that indicates drivers must stop is red. This is a universally recognized signal used in traffic systems around the world. When a traffic light turns red, it means that vehicles must come to a complete halt and cannot proceed through the intersection. This rule is critical for ensuring the safety of all road users, including pedestrians and cyclists, as it regulates the flow of traffic and prevents accidents at intersections.

In contrast, green allows for movement, indicating that it is safe for vehicles to go. Yellow signals that the light is about to change to red, advising drivers to slow down and prepare to stop if they are able to do so safely. Blue is not a standard color used in traffic lights and does not signify any instructions to drivers. Understanding these color signals is essential for safe driving practices and compliance with traffic laws.