Traffic lights are devices used in road intersections or pedestrian crossings to control vehicular traffic and keep pedestrians safe. They are highly useful for orderly and uninterrupted movement of vehicles and pedestrians during heavy traffic on the roads. They play a significant role in controlling the traffic during peak hours without a traffic policeman. Modern traffic lights came into use from the early 20th century.
There are three phase and four phase traffic lights in use. Generally, a traffic signal system has three lights. A green light on the bottom of the signal light stack indicates the traffic to proceed; a yellow light in the middle warns traffic to slow and prepare to stop; and a red light on the top to indicate the traffic to stop.
Traditionally, traffic lights have incandescent halogen bulbs. These traffic lights consume a lot of energy. They are controlled by microcontrollers. With the invention of light-emitting diodes (LEDs), these traditional traffic lights are being replaced with LED traffic lights. The main advantages of LED traffic lights are they are brighter; they save energy and have a longer life span. They consume 83 percent less energy than incandescent bulbs. Depending on size and color, they consume between 8 and 25 watts of energy. But, in the case of incandescent halogen bulbs, their energy use is between 67 and 150 watts.
Most modern LED traffic lights have several additional advantages over incandescent traffic lights. Unlike conventional incandescent lights, they do not use reflectors. They are more visible and have greater light intensity. They have the ability to absorb sunlight that enters the lenses.
Until recently, implementation of LED traffic lights required heavy investment in terms of operations, reliability concerns and high costs. But with the latest technology, LED traffic lights have proven to be economical and a viable solution to save energy. Traffic lights are required throughout the day. Led traffic lights are more efficient and save energy worth thousands of dollars a year.
Source by Marcus Peterson