People are seeing LED electronic displays more and more, and some major roadways have even experimented with LED illumination. What then are the prerequisites for LED street lights?
As the lights are on, the city will gradually get quieter as the day's activity fades into the approaching darkness. Streetlights will be installed on every city street, from the major thoroughfares to the residential neighborhoods' tree-lined walks, to help people find their homes at night. Have you noticed that the majority of our street lights are yellow right now? Unlike white or other colors, why not?
First of all, there are seven hues that makeup light: red, orange, yellow, green, blue, and violet. Red light has the longest wavelength while violet light has the smallest. Various hues of light have varying wavelengths. Red light is more stimulating to the eye than green light since it has a longer wavelength, yet green light is unsuitable because it is the hue of the lighting.
Yellow light typically has a wavelength range of 570–600 nanometers, which is only a relatively sensitive band in the human eye. Yellow light also falls under the warm color category, making it less stimulating to the eye than warm colors like gules and orange. Yellow light is hence the best hue for use in street lighting.
White light was mostly produced by incandescent lamps before the advent of LEDs, while high-pressure sodium lamps were used for a yellow light in street lamps on both sides of the road. The high-pressure sodium lamp is a kind of high-pressure sodium vapor arc discharge bulb. It has a high luminous efficiency at the present time and emits light with a wavelength that falls within the yellow light spectrum of visible light, giving it a yellow appearance to human eyes. The statistics show that high-pressure sodium lamps have a luminescence efficiency that is several times more than that of incandescent lamps, a service life that is twenty times longer, are less expensive and have superior fog permeability. Yellow light is very sensitive to human eyes, and since it makes people feel warm, it helps decrease the likelihood of nighttime traffic accidents.
High-pressure sodium lights do, of course, have several drawbacks. Poor color rendering is the fundamental drawback of high-pressure sodium lamps. One assessment index for the light source is color rendering. In general, it refers to the contrast between the color of the object and the color displayed by the light source. The color rendering of the light source is improved the more closely the display color resembles the actual color of the item. It is possible to use incandescent lamps for home lighting and other lighting scenes because they render colors well. However, the sodium lamp's color display is subpar; regardless of the object's color, the past appears yellow. In the right amounts, road lighting does not overly depend on the color of the light source; as long as we can spot a car coming from a distance, we can determine its size (shape) and speed without having to tell whether it is red or white.
