Blue light apparently suppresses the production of melatonin which helps you sleep at night. And it’s not just ... The benefits of LED lighting are huge, however. From an energy-efficiency ...

Question: I’m wondering about a light that seems to only be on at night on the traffic lights ... Answer: What you are talking about is a blue light and they are visible during the day.

Question: I’m wondering about a light that seems to only be on at night on the traffic lights ... Answer: What you are talking about is a blue light and they are visible during the day.