Motion Sensor With Timer How Do Stoplights Work? A Timer? Motion Sensor?

How do stoplights work? A timer? Motion Sensor? - motion sensor with timer

There are several methods. The most common reason is a "circuit cut" in the same way, and if a vehicle is more than "Loop") is an electric system (magnetic disturbance takes place, so no sign of recognition. In addition, the fires of May or enter on a timer for each address, a certain amount of time. There are also devices like the arms of the camera mast itself can see the traffic and determine the direction it needs a green-red signal. Worse, if an emergency vehicle to cross an intersection, there are devices called Opticom in the arm of the pole, change the type almost immediately at the crossing on the emergency vehicle, a green light.
I'm no expert, but working with the electricians of the local community, and that's what I learned over the years.