I don’t understand how they work, what they’re hooked up to and how they know when to turn from green, to yellow, to red. Are they timed? Is there a sensor, perhaps a small man hiding in the pole controlling it?
In: 7
It’s a combination of sensors, timers and direct control.
Major intersections generally have sensors at the first and sometimes second queue position to detect if cars are there and need to change the lights.
In some peak tines, the intersection is generally set to specific timing, or can be controlled by the city wide traffic control inordrr to give more time to certain directions.
In off peak times (generally late at night) the intersection lights stay in the direction of major travel, and only change if there is a vehicle detected, or the pedestrian crossing button is pressed.
In emergency situations, traffic control for whole regions can be manually overridden.
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