Traffic signal work usually begins with which phase of construction?

The correct answer is the phase of underground construction. This initial phase is crucial for traffic signal work, as it involves the installation of essential infrastructure beneath the ground, such as conduits and wiring that power the signals and connect them to the traffic management system. Proper underground work lays the foundation for all subsequent traffic signal activities.

Once the underground systems are in place, the following phases can be executed more efficiently. For example, activities such as overhead installations or surface work rely on the groundwork being completed first. In this way, the underground phase serves as a critical step that supports the overall functionality and accessibility of the traffic signal system. Final sign placement comes last, as it is dependent on all prior work being completed to ensure that signs are properly positioned and operational.