What is LED Street Light and How do they Work?

LED technology has witnessed major advancements over the years. Light Emitting Diode products are not just used for small-scale purposes such as in small electrical appliances. Their usage has spread across almost every sector of life. Most streets in the major cities of the world depend on LED street lighting. There are several reasons that are behind this kind of revolution. The effectiveness of LED lighting over other lighting systems is just one of the reasons. This article is going to give you critical information on what LED street lighting is and how they work.

What is LED Street Light?

An LED street light is simply an integrated lighting system whose source of light is light emitting diodes(LEDs). It is referred as an integrated system because the lighting unit acts a single unit rather than spate fixtures. During the manufacturing process, a group of LEDs is enclosed panel. They are then transferred to another bigger LED panel that also houses a heat sink to form a luminaire.

LED street lights come in different shapes and designs. The variation depends on various factors such as the configuration of the LED. Other factors such as the shape of the heat sink used and personal preferences also play a critical role in determining the overall design.

How LED Street light Works

The building block of an LED street lights is numerous light emitting diodes. These are semiconductors that emit light when subjected to an electric current. Let’s look at the working mechanism of these semiconductors.

The Mechanism of LED

LED is a semiconductor diode. This means that electric current flow through it in one direction only. Since LED is a p-n junction diode, the electrons and the holes can combine when there is an adequate supply of electric current. Once the electrons join the holes, they release energy in form of a photon. This energy is responsible for the lighting effect of the LED.

The color and intensity of the light depend on the energy of the photon. On the same note, the photon depends on the energy band of the diode that is used. This is why you see different LEDs emitting different colors and brightness. These aspects are put into consideration in determining where the LEDs should be used. As expected street lighting function requires LEDs that are capable of releasing high-intensity light. Most electronic appliances use multi-colored LEDs for different purposes.


Another component that facilitates proper functioning of LED streetlights is the heatsink. This is a common part of most electronic appliances whose operations result in the dissipation of heat energy. In the LED street lights, heatsinks facilitate the smooth flow of air from the main system. As we already noted, the flow of current through the electrons results to a spasm of energy which is converted to light (photon). A portion of this energy is converted to heat which needs to be eliminated as fast as possible before it causes physical damage to the system. Poor circulation of air and heat control can reduce the lifespan of the LED streetlight.
Another key factor that determines the lifespan of the LED streetlight is the intensity of the output light in relation to the original specifications. An LED street light is considered dead if its brightness reduces by 30 percent.

LED streetlights have lenses that are located on the LED panel. They are responsible for conveying light to the desired direction in a rectangular pattern. This feature makes LED street lights different from the conventional street lights. Traditional street lights depend on a shiny surface that acts as a reflector. With this mechanism, most rays end up getting lost while others illuminate to undesired areas leading to light pollution. Conventional Streetlights are also known for causing a glare-a problem that affects road users especially motorists.

Directional Lighting

Unlike the conventional streetlights that produce a glow, LED street lights produce a directional light. This is the case where light is directed to illuminate towards a certain direction or specific areas. Some LED streetlight fixtures can be dimmed depending on the time, the need and the traffic. For instance, the brightness can be increased when many people are on the streets. You cannot find such levels of flexibility in traditional street lights.

Energy Efficiency

The operation of LED street lights ensures that they consume less energy as compared to their traditional street lights counterparts. Most conventional street lighting systems use high-pressure sodium (HPS) which is known to be a heavy consumer of electric energy. When it comes to the output, LED still gives high-intensity light as compared to a traditional bulb.

Long Lifetime

After the installation of LED street light, it may take several years before you consider doing a replacement. They have long lives that can go up to 15 years. LEDs are immune to common issues that affect street light such as burnout. This feature is totally opposite to HPS and fluorescent bulbs as they are known for constantly burning out. LED street lights are also predictable. They don’t just stop working abruptly. You will know that its lifetime is almost coming to a halt once its brightness starts reducing gradually. On the other hand, conventional street lights will just stop without showing early warnings.

Instant reaction

A traditional street light will take some minutes before it fully brightens up. This is because its components such as metal halide mercury and sodium vapors need some time to heat up before glowing. LED street light has a different working mechanism. It brightens up fully immediately after switching it on. The same applies to the restarting process after a brief interruption. This is possible because LEDs don’t depend on external components and gases.


From a general observation, it is crystal clear that LED street lighting faces a brighter future ahead. Its way of operation does not cause any kind of pollution to the environment. The prolonged lifetime of LED street lights helps to cut down on the accumulation of e-waste. It leaves no question why most modern cities are lit by LED street lights.


1. http://science.howstuffworks.com/environmental/green-tech/sustainable/led-streetlight2.htm
2. http://www.nytimes.com/2009/05/30/science/earth/30degrees.html
3. http://blog.mlive.com/michigan/2008/04/study_new_street_light_technol.html
4. https://web.archive.org/web/20150720203034/http://www.northernlights-direct.co.uk/led-street-light/

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