Retroreflectors are devices that operate by returning light back to the light source along the same light direction.
Reflector is used on road surfaces, road signs, vehicles, clothing and hanging accessory. When the headlights of a car hit a retroreflective surface, the reflected light will return back directly towards the source of light and the driver of the car. However, a pedestrian can see retroreflective surfaces in the dark only if there is a light source directly between them and the reflector (e.g., via a flashlight they carry) or directly behind them (e.g., via a car approaching from behind).
