A streetlight is a light bulb on a pole used for lighting streets. Streets can be lit for safety or visibility reasons, so people can see where they are going at night.
There are five main types of streetlight:
- An LED streetlight gives a white light, and the lantern is usually short and thin because each LED is small.
- A mercury vapor streetlight gives a green-white light, and the lantern is usually short.
- A metal halide streetlight gives a white light, and the lantern is usually short.
- A low pressure sodium streetlight gives a yellow light. The lantern is usually long, because low-pressure sodium lamps are shaped like a tube.
- A high pressure sodium streetlight gives an orange-white light, and the lantern is usually short.
Many countries are replacing, mercury vapor, metal halide and sodium vapor streetlights with LED streetlights, because LED streetlights are cheaper to run. However, some models integrate the LED panel in a way that the whole lantern must be replaced, if the panel burns out or breaks down.
