What is the main application of a light sensor in street lighting?

The primary application of a light sensor in street lighting is to control light switches based on ambient light. These sensors detect the intensity of natural light in the environment and automatically switch street lights on when it becomes dark and off when there is sufficient daylight. This functionality not only enhances energy efficiency by ensuring lights are only on when needed but also improves safety and convenience for pedestrians and drivers.

In contrast, the other options do not align with the function of light sensors in this context. Detecting pressure changes pertains to pressure sensors, regulating temperature relates to temperature sensors, and measuring humidity levels involves humidity sensors. Each of these serves different purposes and does not apply to the specific task of managing light levels for street lighting.