A street light is a raised source of light on the edge of a road or walkway, which is turned on or lit at a certain time every night. Modern lamps may also have light-sensitive photocells to turn them on at dusk, off at dawn, or activate automatically in dark weather. Major advantages of street lighting includes: prevention of accidents and increase in safety. The major criticisms of street lighting are that it can actually cause accidents if misused, and cause light pollution.