What are the Advantages of LED Traffic Lights?

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  • Written By: Michael Pollick
  • Edited By: Niki Foster
  • Last Modified Date: 21 March 2020
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The next time you stop at an intersection, take a closer look at the glowing red light. If it looks like a honeycomb of bright red dots, you are enjoying an example of LED traffic lights. Cities around the world have been systematically replacing their older incandescent bulb-based traffic signals with the more energy efficient LEDs since the mid-1990s. These traffic signals have several advantages over incandescent models, but the three main advantages are improved visibility, longer shelf life, and lower energy costs.

The development of commercially feasible LED traffic lights was originally hampered by the limitation of Light Emitting Diodes (LEDS). LEDs generate light as a result of electrical current running through certain gases. At first, LEDs could only produce the color red, which limited their use to monochromatic devices such as alarm clock displays or calculators. Further refinements in the technology have now produced the three colors used for traffic signalling: red, amber and green.

One major advantage of these traffic lights is increased visibility. Incandescent bulbs were often covered by color filters, reflectors, and glass lenses, which could affect how much light actually reached drivers' eyes. LED traffic lights use an array of bright LEDs that do not require additional filters or amplification. If a single incandescent bulb burns out, the entire light sequence is disturbed. Several LEDs can fail in these lights without causing a noticeable disruption. A catastrophic failure involving all of the LEDs in a panel would be rare indeed.


Another advantage is lower maintenance costs. Almost all of the cost of LED traffic lights are upfront — LEDs are expensive, and the signals themselves require more labor to produce. These expenses are usually offset by lower maintenance costs. If an incandescent bulb burns out, which happens three times a year on average, a trained city employee must replace the bulb while traffic is diverted. LED lights, on the other hand, may only require a yearly cleaning of the protective lenses. The individual light panels often last ten years or more, depending on the conditions.

On a related note, another advantage of LED traffic lights is noticeable energy savings. A standard incandescent lightbulb may use 100 watts of electrical power to produce light, but an equivalent LED panel uses 15 to 20 watts to achieve the same intensity. Considering how many thousands of incandescent lightbulbs must be lit around the clock, it is easy to see why LEDs are so appealing to cities on tight energy budgets. Larger cities can save substantial amounts of money by switching to LED traffic systems. Some cities that have converted still maintain an incandescent amber light, since it does not remain lit for as long as the green and red signals.


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Post 5

Can an LED Traffic signal still need a back panel and visors?

Post 4

As the traffic engineer for a midsized city in Georgia, I can attest to the experience of early failure of the LED inserts. The majority of the failures are related to the power supply on the circuit board. We have returned several to the manufacturer, who replaces the bad power supply and sends the insert back. In all, the LED inserts perform exceptionally well and I anticipate even better as the technology matures.

Post 3

Actually, I am one in sales in the LED industry. the led is long life only in the certain conditions when the electric current is stable in such as 125 ma -130 ma. If not, it will easily burn out. So if you want good traffic lamps, you also need a good electrical power supply to supply a stable current. and also the good led.

Post 2


I have done a bit of research to attempt to address your concerns, and it seems that LEDs, no matter their use, are widely praised for their long life.

I wonder if there's another answer to the poorly-functioning traffic lights you bear witness to? Poor product? Shoddy installation? Maybe they really have been there long enough to warrant replacing?

Post 1

Dear wiseGeek, regarding the "long life" of LED

traffic lights, have you measured it? I've been observing such lights installed in Mountain View,CA over the last few years, and more recently within the year in San Jose CA. I'm seeing a lot of burned out LEDs.

The failures tend to occur with big clusters of multiple leds going black, or flickering on and off. The overall effect is of cracked glass, with wedges of darkness, triangles, circles, blobs, etc.

The long life claim is bogus. Please collect some data from a traffic department.

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