Road Studs: It is a retroreflective safety device used in road marking. Road studs with proven successful installation in various locations such as motorways, walkways, car parks and cycleways, these road studs provide guidance and advanced warning to drivers. They are are particularly valuable in fog and are largely resistant to damage from snow ploughs. Dev Plastics have categorised them in two types based on the material used i.e. plastic and aluminium.