Reflective cones are used to increase the visibility of a hazard or restricted area, primarily for traffic management and safety. They are used to mark temporary lane closures, roadworks, and construction sites, as well as to create safety perimeters during emergencies or events. The reflective strips on the cones bounce light from headlights and other sources, making them highly visible in low-light conditions and bad weather, which is crucial for preventing accidents and protecting both the public and workers.