How Traffic Lights Work

How Traffic Lights Work

When you look at the way society has advanced over the span of human existence, there is no denying that lighting has played an important role. While lighting is important for the visibility it brings to both residential and commercial spaces, one of the most impactful to daily life can be seen on the roadways. The traffic light is a lighting marvel that is definitely an essential part of modern curiosity. Let's take a look at how traffic lights work for a closer look at this lighting necessity.

Two Types of Operation

When looking at how traffic lights work, most people are surprised by their simplicity. We expect their operation to be more complicated, but even the design of the signal is rather simple consisting of a controller, traffic light heads, and detection components. The controller houses the information and power to activate or illuminate the traffic light heads based on a sequence determined by the detection component.

While the basic design of a traffic light is the same in every model, the mode they operate on can be one of two options. Lights can operate on fixed time which is where the light will cycle through the sequences of yellow, red, and green on a fixed time frame. While this is ideal for busy intersections, it can be less ideal for intersections where one direction may have heavier traffic than other roads included in the intersection. This is where vehicle actuation operation comes in and the light responds to traffic flow by volume rather than a set timer for all sides. This mode of operation is done by the detection components detecting how many cars pass under the light in each direction and then adjusting the cycle, or sequence of yellow, red, green, in accordance to meet the flow of traffic in multiple directions with streets with heavier volume receiving more green time to avoid backups.

LED Technology

When looking at how traffic lights work, it is also worth noting that LED has played its part in their advancement. LED technology has been installed in traffic signals in many cities around the country thanks to a few important benefits of LEDs. For starters, LED lamps last longer than other solutions while also consuming a lower wattage for better savings for the city. LED also lasts a long time which means cities have to change bulbs less frequently. The only drawback to using LED in traffic signals is that they still have a way to go in advancing their ability to withstand exceptionally harsh winters. Since LED doesn't produce any heat, it is believed that incandescent is still the better choice for locations with extreme winter temperatures.