What action must you take if a traffic light is not functioning?

When a traffic light is not functioning, treating it as a four-way stop is the correct action because it establishes a clear protocol for drivers at an intersection where there might otherwise be confusion. In this situation, each vehicle approaching the intersection must come to a complete stop and yield to any vehicles or pedestrians already in the intersection, or to those that arrive first. This helps maintain safety and order on the road when traffic signals are non-operational.

Continuing to drive without stopping may lead to dangerous situations, as drivers may assume they have the right of way, which can result in collisions. Calling the police for assistance is not necessary in most cases unless there is an immediate danger or a serious accident has occurred. Ignoring the light and following traffic signs could also create hazards, especially since traffic signs may not provide complete guidance in the absence of working signals. Therefore, treating the situation as a four-way stop is the safest and most responsible action to take.