Switchable retroreflecting films are the new type of retroreflector by modulating (flashing) the retroreflected light for enhanced visibility and night vision applications. There are five types of viable constructions and operating mechanisms for switchable retroreflector, including integrated electrowetting scattering, integrated and external electrowetting light valve, external liquid crystal light valve and external liquid crystal scattering. This paper gives broad comparison and discussion about the characteristics of five technologies for further development of switchable retroreflecting films.