By reducing the supply voltage, HPS street lights can be dimmed. At midnight, when there is little need for light, the power is slowly lowered to reach a low power state. The control devices, like the autotransformer, relays, etc., are usually in the dimming cabinet. And the cabinet connects a stretch of street lights. The reducing process is slow and requires small steps to make sure the light won’t extinguish because of the voltage drop.
More reading: LED Street Lights VS HPS Street Lights: What’s Better in 2023?
