What is the primary use of a portable generator in traffic signal systems?

Answer: C — For backup power during outages

The primary use of a portable generator in traffic signal systems is for backup power during outages. In situations where the main power source is interrupted—due to outages from storms, accidents, or maintenance needs—the portable generator steps in to provide the necessary electricity to keep the traffic signals operational. This is crucial for maintaining traffic flow and ensuring safety at intersections, preventing accidents that could occur if signals were to go dark. While continuous power supply and testing signals might be important in different contexts, the primary role of a portable generator revolves around its ability to act as a temporary power source, thereby ensuring that traffic management remains effective during emergencies or disruptions. Recharging batteries might be a function of certain backup systems but does not encompass the main purpose of a portable generator in this context.