What procedure must be completed to confirm that work on a traffic signal has been successful?

To confirm that work on a traffic signal has been successful, conducting functional testing and inspection after maintenance is essential. This procedure ensures that all components of the traffic signal system—such as the controllers, lights, and detectors—are operating correctly and as intended. Functional testing goes beyond just visually checking the equipment; it involves actual performance checks to validate that the signal cycles function, timing is accurate, and all safety measures are in place.

Functional testing also helps identify any issues that may not be visible upon initial inspection, such as electrical failures or misconfigurations in the signal programming. This comprehensive approach is critical for safety and efficiency in traffic management, ensuring that the signal will perform reliably before being fully put back into service.

While a visual inspection can provide a preliminary check of the signal's condition, it does not verify operational effectiveness. Software updates and change monitoring, while important at times, do not directly confirm the successful implementation of maintenance or repairs. Thus, functional testing combined with thorough inspection is the best method to ensure that the work performed on the traffic signal has been completed successfully and meets all requirements.