As with any lighting solution, roadway lighting needs to be chosen with care keeping in mind the final desired result. While there are many factors to look at, such as efficiency, lumen output, fixture type, and durability, the issue of color temperature should never be overlooked. Let’s take a closer look at the matter of color temperature in relation to roadway lighting.
What is color temperature?
If you are new to lighting, color temperature is the color appearance of a light solution output. It is measured and recorded in the unit of Kelvin and abbreviated to CCT for correlated color temperature. Warm temperatures will be more on the yellow side and have a CCT of around 2700K whereas as a cooler light will have more of bluish hue with a CCT of around 5000K.
Which temperature is right for roadway lighting?
The various CCT ratings leave a lot of options in terms of lighting temperatures. However, not all temperatures are best suited to every location. When planning the correlated color temperature for roadway lighting the most important issues are visibility and light pollution. While you may think the brighter and cooler the better for visibility as the main concern, light pollution and visibility need to work in tandem with each other instead of opposing for the best result. To factor in the needs for light pollution and visibility, consider the roadway type. If it is a small residential road, the most common choice is to keep it under 4000K. The closer a light is to the bluish white of a cool temperature, the more closely it mimics daylight which can be a problem in residential areas at night when trying to sleep. For major roads and highways, a higher CCT is recommended to improve alertness.
What about lumens?
Many people confuse the matter of CCT and lumens. They assume that because the light is a warmer temperature, they need to increase the lumen output for better visibility. It is important to note that lumens are about illumination or perceived brightness to the eyes whereas color temperature is about the color of the light. You should closely consider the relationship between the two to get the best result overall, but don’t feel it is necessary to up the lumens to try to compensate for the warmer tone since it isn’t required.