Introduction：
When driving at night, you may ask: why are street lights yellow instead of white or some other color? Indeed, we tend to think that white light is more apparent and yellow is dimmer. But the street lights use yellow; is it to bring a touch of warmth to you when you return at night? What is the difference between yellow and white street lights? The following will introduce you in detail.
Why are street lights usually yellow or orange?
Why are street lights yellow instead of white? Firstly, we need to figure out why the street lights emit yellow lights. It is determined by the light bulb used. Most street lamps are made of sodium vapor, which is mainly divided into high pressure sodium(HPS) and low pressure sodium(LPS). High pressure sodium is used more because it has higher luminous efficiency, consumes less power, and lasts longer. And its fog permeability is also excellent, making it safer to travel at night and reducing the probability of traffic accidents.
But the high pressure sodium lamp also has the disadvantage of poor color rendering. It appears white when first opened and turns yellow after a while. No matter what the object is, it is yellow. Reading this, you may be asking, why not use a clearer incandescent light? That’s because, for road lighting, color rendering is not that important. In the process of driving at night, you only need to see the size and shape of the oncoming car, not the car’s color.
Why was sodium used in street lighting?
Simply, the street light is yellow or orange because it uses high pressure sodium; Why was sodium used in street lighting?
First of all, let’s look at a table, which is the average rated life and lumens per watt of different types of bulbs.
| Types of bulbs | Average rated life | Lumens per watt |
|---|---|---|
| Incandescent | 750-2,000 hours | 12-18 |
| HPS | 20,000-24,000 hours | 80-140 |
| LED | 40,000-50,000 hours | 30-90 |
| Halogen | 2,000-4,000 hours | 10-20 |
We can clearly see that the HPS has about seven times more lumens per watt than incandescent bulbs, and it can last up to about 24,000 hours. Therefore, the sodium light is bright enough and has a long service life.
Another important reason is that it consumes less power. Because it only produces light visible to the human eyes. Incandescent lamps produce light in all frequency ranges from infrared to ultraviolet, which is very power-hungry.
Therefore, sodium lamps have apparent advantages in terms of cost and efficiency compared to other light bulbs, so why not use sodium lamps? Since the 1980s, HPS lamps have been widely used in street lights, and people have gradually become accustomed to yellow street lights.
Why aren’t LED street lights used?
Incandescent lamps are not used in street lights for efficiency reasons, but why aren’t LED street lights used? After all, when we look at the table above, LED is efficient and has longer average rated life. Two main reasons are described below.
1. Appearance time
In fact, it wasn’t until 1962 that Nick Holonyak invented the first visible LED light. This is much later than other types of lamps. By this time, many street lights were already in place. Widespread application of new technologies requires practice, which cannot be accomplished in a short period.
2. Cost
And the cost of LED lights is also high. An LED light bulb cost about $200, which was a lot of money at the time. And street lighting requires not only light bulbs but also poles and other materials. Installation is also labor-intensive.
But over the years, the price of LEDs has been falling, and some street lights have begun to use LED lights. There is no doubt that as technology advances, we will see LED technology applied to more fields. But we need to know, under the circumstance that there are no apparent disadvantages of the sodium lights, the LED lights will not replace the sodium lights.
The best LED street lights manufacturer
If you want to buy high-quality LED street lights, you have to choose a reliable LED street lights manufacturer, and then your buying journey is half the battle.
Kanglight is one of the best LED street lights manufacturers in China. It is well-known in China even because of decades of experience in manufacturing and exporting street lights. Kanglight street lights manufacturer can provide you with many kinds of high-quality LED street lights and excellent service!
Here are some kinds of popular LED street lights for your reference.
1. VEGA Series Cobra Head Street Lights
VEGA family series(cobra head led street ligh) is a world-class success. As a kind of high-quality street light, it is widely used in urban residential areas, commercial areas, parking lots, highways, etc. In high-temperature conditions, it is UV resistant. After a heavy rainstorm, it can drain rainwater and dirt. It also has reasonable temperature control.
2. LIBRA Series LED Street Lights
In order to satisfy customers’ diverse needs, Kanglight street lights manufacturer is dedicated to bringing new design libra lighting to them. LIBRA Series LED Street Lights are used on highways, urban roads, and streets in municipal, commercial areas, residential areas, car parks, motorways, running/biking paths, and more.
3. Pisces Series LED Street Lights
Pisces Series LED Street Lights can be applied to any streets you can think of, such as commercial areas, residential areas, highways, and more. It also has an excellent temperature-controlled self-cleaning feature. Without a doubt, it was also a great success.
Conclusion:
Why are street lights yellow instead of white? I think you will have an answer after reading this article. In short, the flashing yellow street light is not the cause but the effect. We often see yellow street lights simply because they are the most cost-effective option when installing street lights for the first time. Of course, they also have drawbacks, such as they make it challenging to identify the color of a car. If you use white street lights, you can do an excellent job of identifying colors. Therefore, we can expect LED street lights to be better applied in the future. Do you prefer white street lights or yellow street lights? If you have any ideas, please feel free to communicate with us.
