Why Don`t We Use Red Lights at Night in Street Lamps?

The Problems with Red Light

Lower CRI:

CRI, or color rendering index, is a measure of how well a light source reveals the true colors of objects. The higher the CRI, the more natural and vivid the colors appear. Red light has a very low CRI, since it is a monochrome light that only contains one wavelength of the visible spectrum. This means that many objects cannot reflect red light, and therefore appear black or dark under red light. This can make it difficult to see details and distinguish objects, which is dangerous for street lighting.

Causing confusion:

Red light is also associated with other signals and signs, such as traffic lights, brake lights, emergency vehicles, etc. If street lamps use red light, it can create confusion and reduce the visibility and contrast of these important signals. This can lead to accidents and misunderstandings, especially for drivers and pedestrians.

Making you sleepy:

Red light may help you sleep better, but it can also make you sleepy when you are not supposed to. Red light is often used in the bedroom or in dim environments, because it increases the secretion of melatonin, a hormone that regulates our sleep cycle. However, if street lamps use red light, it can make people feel drowsy and less alert, which can impair their performance and judgment.

The Alternatives to Red Light

White light:

White light is the most popular and widely used color of light for street lighting. White light has a high CRI, which means it can show the true colors of objects and enhance the visibility and clarity of the environment. White light also has a positive effect on our mood and alertness, as it mimics the natural daylight and stimulates our brain activity. However, white light also has some disadvantages, such as causing glare, light pollution, and disrupting our circadian rhythm and melatonin production, which can affect our sleep quality and health.

Yellow or orange light:

Yellow or orange light is another common color of light for street lighting, especially for high-pressure sodium (HPS) lamps, which are widely used for their high energy efficiency and long lifespan. Yellow or orange light has a low CRI, which means it can distort the colors of objects and make them appear dull and yellowish. However, yellow or orange light also has some advantages, such as being less harsh and glaring than white light, creating a warm and cozy atmosphere, and having less impact on our circadian rhythm and melatonin production, which can help us sleep better.

Green or blue light:

Green or blue light is a relatively new and experimental color of light for street lighting, which is mainly used for LED lamps, which are more energy-efficient and environmentally friendly than HPS lamps. Green or blue light has a high CRI, which means it can show the true colors of objects and enhance the visibility and contrast of the environment. Green or blue light also has a positive effect on our mood and alertness, as it mimics the natural daylight and stimulates our brain activity. However, green or blue light also has some disadvantages, such as causing glare, light pollution, and disrupting our circadian rhythm and melatonin production, which can affect our sleep quality and health.

Conclusion