A street light is exactly that, a light that illuminates the road, or pavement, beneath it.
Also commonly known as lamp-posts they are installed to provide lighting during periods of darkness or in areas where natural lighting cannot reach, such as tunnels. By doing so, they help to improve both the safety and security of those using the road.
They also hint at the speed limit of a road; in the United Kingdom, regularly spaced lighting denotes that the speed limit is 30mph unless signage states otherwise.
Street lighting has very early origins, so sit back and enjoy a ride through illuminated time.
A street light is much more than a box with a bulb in it, in fact they are quite sophisticated; this page explains how.
There are over one hundred different varieties of street light that can be seen on Britain's roads; this is a guide to some of the more common examples you are likely to encounter.