A signal light is a visual indicator used to convey information or instructions, often in traffic management or industrial settings. These lights can change colors, typically red, yellow, and green, to signal stop, caution, or go, respectively. They help ensure safety and order by guiding the actions of drivers and pedestrians. In addition to traffic control, signal lights are also used in various applications, such as railway systems and airports. They can indicate the status of equipment or alert personnel to specific conditions, enhancing communication and operational efficiency in different environments.