One of the banes of city living is traffic. But for the traffic signals, the traffic would be chaotic leading to accidents, jams, and even deaths. But, did you ever wonder how do these traffic signals work? Despite the traffic, how do these traffic signals work collaboratively and in tandem with each other, even though they are inanimate objects? Well, the answer lies in the controller that is present within each and every traffic signal. Let’s see how these traffic signal controllers work.
A traffic signal primarily comprises a traffic signal controller, vehicle detector, traffic signal lanterns or lights, posts, pedestrian push buttons and underground electrical wiring to connect all these different aspects with each other.
In this entire gamut of components, the traffic controller is considered to be the ‘brains’ behind the entire operation. The controller primarily houses a computer that detects, analyzes and processes the information that it receives from its detector and push buttons and changes the traffic light accordingly. Depending on the traffic demands in the city, a traffic signal controller usually determines how long the green signal stays on for each phase or traffic movement. It also controls the transition from a green signal to a red signal. Traffic signal controllers are also one of the most versatile gadgets. They can operate in a stand-alone manner and can also be programmed to collaborate and coordinate with other traffic signals.
The traffic controller works on two different methodologies. These are:
Many traffic controllers are often programmed to follow the fixed time operation. In this operation, the controller enables the traffic signal to show green for the same amount of time, irrespective of the traffic. While the fixed operation works wonderfully in a heavily congested road, it is not used optimally in places where there is very little traffic. In an area where there is very little traffic, a fixed time phase is often considered to be useless, as then the traffic signal can be programmed to follow other effective operation methods.
One of the most commonly used operations methods is the vehicle actuation operation. In this operation, the traffic signal controller detects and takes in to account the vehicle demands on all roads and enables the traffic signal to show green.
The traffic signal controller detects the vehicle demands through detection units that are installed over the signal heads or on the carriageway. It then analyzes and processes the information and allocates the right amount of time that a green signal should stay on or the right amount of time the red should stay on for each and every road. Here, you should remember that the controller is already programmed with the minimum and maximum times the green should be on and this cannot be changed. How this works you might ask? Well, the traffic signal controller detects the number of cars that pass through its detector and depending on the traffic and the information it receives from the grid, it turns the green signal on. In this case, any car that will pass through will extend the time of the signal.
The traffic signal controller’s job doesn’t seem as easy as it looks. Other than, keeping a close watch on the current traffic (vehicle and pedestrian), the traffic signal also has to consider all the information it receives from the traffic signal network to ensure a smooth flow of traffic in the city.