semafores
Semafores, also known as traffic signals, are devices used at road intersections to manage the movement of vehicles, pedestrians, and cyclists. They use colored signals—red to stop, yellow to prepare to stop, and green to proceed—with variations for turning movements or pedestrian crossings.
Components: signal heads with lights, a controller or control cabinet, sensing devices (such as inductive loop
Operation: Signals may be fixed-time, cycling through phases on a timer; actuated, extending or shortening phases
Safety and planning: Proper placement, visibility, and synchronization reduce delays and prevent collisions. Transit priority and
History and variation: The concept emerged in the early 20th century with electrical signals becoming common;