Why Are Street Lights Orange?

June 14, 2023

The majority of contemporary street lights in America emit orange light, but it's not by design. The orange glow is actually a side effect of the bulbs that are used. The vast majority of street lights use low-pressure sodium (LPS) or high-pressure sodium (HPS) bulbs that are unable to produce white light but can only glow yellow and orange.

Historically these bulbs were the most economical way to illuminate a large area because they are very efficient in that they provide lots of intensity for the amount of electricity used. They also consume less energy than other types of bulbs but they do have some drawbacks. Specifically, they produce lots of light pollution that interferes with the natural nighttime environment. This can cause problems for animals that rely on the dark to hunt or migrate and it can disrupt people's sleep cycles.

As technology advances though, we're seeing a lot of these orange bulbs getting replaced with LEDs that can glow very brightly in a pure white color. The change isn't going to happen overnight, but it's gaining momentum. This change isn't just good for our electricity bills, it's better for safety as well. Studies have shown that when drivers are exposed to white light it doubles their peripheral vision and reduces their braking times compared to orange-lit roads.

In addition to safety, there are a number of other reasons that people are excited about the switch to white lighting. Many streetlights are old and need to be replaced anyway, so this is an opportunity to make a better looking and more efficient replacement. In addition, the downward focus of these new LED bulbs will likely help cut down on light pollution and potentially allow us to see more stars at night.


Traffic Dave is on a mission to help traffic engineers, transportation planners, and other transportation professionals improve our world.
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