Dusk to Dawn LED parking lot lights are pole lights which have sensors, called photocells built in that help identify when it is daytime or nighttime. The lights will automatically come on at dusk as the sun sets and come off at dawn when the sun rises with the help of photocell.
The lights have a photocell in them to help identify the changes of the sunlight or ambient light. This is measured in the scientific term Lux. Lux is a measurement of light at a certain place.