Because LED and high pressure sodium lamps are better than low pressure sodium lamps. Low pressure sodium lamps are not as good as them for the following reasons:
- Light efficiency: The efficiency of low pressure sodium lamps is about 50-100 lm/W, which is lower than that of LED lights.
- CRI: Low pressure sodium lamps have a low CRI and emit yellow light. This light cannot provide clear vision.
- Starting time: Low pressure sodium lamps have a long starting time, which can be up to 30 minutes. However, LED street lights can turn on instantly.
More reading: LED Street Lights VS HPS Street Lights: What’s Better in 2023?