The traffic light now and days are seen all over the world with one soul purpose and that is to control traffic. As time goes by, cars and trucks are increasing in horsepower and with the increase of horsepower come higher speeds that can be reached. If it was not for the traffic light being installed all over the world, could you imagine the fatality rate in the world today? The traffic light has gone a long way since 1920. The idea of the traffic light has sparked new and improved ideas for its use. There are many different variations of traffic lights that have been improved in some way. Something as simple as the traffic light bulb has been changed to be more energy efficient. It went from having a being an incandescent or halogen bulb to light emitting diodes most likely known as the LED light. The LED has many more advantages over the halogen or incandescent bulbs. LED is of course more energy efficient and also had a longer life span that the other bulbs. If the halogen or incandescent bulb blew, the traffic light would be out of commission until someone got there, which would take up manpower, time, and money. With LED, you know longer have this problem of a traffic light being out of commission. If a LED light blew, there are still enough lights to illuminate the traffic signal.
One of the biggest improvements in the traffic light is the inductive loop traffic detector. These are the rectangular pads you see on the roads that are in front of traffic lights. Underneath these pads are loops of wire wrapped around a piece of iron. This then causes an electromagnetic force. Since a car is made of metal, the inductive loop traffic detector detects the car. This sends a message to a computer that you might find near the intersection in a metal rectangular shaped box and tells the traffic light to change. In most cities and heavy traffic regions, this is not the case. In cities and places with heavy traffic, the traffic lights are on a timing system through the computer. The timing on changing the traffic light is different; it is based off of the amount of traffic in the area.
Here is schematic of how the traffic light detection works: