A safety reflector is a retroreflector intended for pedestrians, runners, motorized and non-motorized vehicles. A safety reflector is similar to reflective stripes that can be found on safety vests and clothing worn by road workers and rescue workers. They are sometimes erroneously called luminous badges or luminous tags, but this is incorrect as they do not themselves produce light, but only reflect it.
A safety reflector aids visibility of a person or vehicle visible to on the road, as it reflects light from headlights of vehicles. Safety reflectors are especially useful where there are no streetlights.
Unlike reflective stripes that are permanently fixed to clothing, the safety reflector is a stand-alone device that can be attached to any article of clothing as needed, often using a safety pin and some string. For vehicles, the reflector is usually a fixed part. In bicycles, reflectors are usually on wheels, pedals, under the seat, on the back of the luggage rack, and in front of the front fork. In motorcycles, automobiles, and other vehicles, reflectors are built into the front and rear ends (and sides) next to the headlights and breaklights.
Within the European Union, safety reflectors for pedestrians must be certified to comply with the CE EN 13356 safety standard. This standard is specifically for "loose, reflective accessories for personal use". There are other standards for other types of reflectors such as safety vests and reflectors on bicycles.
In Finland and Estonia, pedestrians are required by law to wear safety reflectors when walking during dark conditions.
The reflector is claimed[by whom?] to be a Finnish creation, invented by a farmer Mr. Arvi Lehti from Pertteli, a small township in Western Finland. The inventor did not consider pedestrian safety when creating the first reflectors: he simply wished to protect his horse carts and carriages. Reflectors were introduced to Finns in 1960. Nowadays one can find reflectors of all possible shapes and colours, as design and fashion industries have turned their faces towards this diminutive gadget. Special 'clip-on' reflectors for bicycles and other human-powered vehicles are also common.
A bicycle reflector or prism reflector is a common safety device found on the rear, front and wheels of bicycles. It uses the principle of retroreflection to alert another road user of the bicycle's presence on the road.
The reflector is usually manufactured in the form of a moulded tile of transparent plastic. The outside surface is smooth, allowing light, such as from a car's headlights, to enter. The rear surface of the tile takes the form of an array of angled micro-prisms or spherical beads.
The light striking the rear, inside surface of the prisms or beads, does so at an angle greater than the critical angle thus it undergoes total internal reflection. Due to the orientation of the other inside surfaces, any light internally reflecting is directed back out the front of the reflector in the direction it came from. This alerts the person close to the light source, e.g. the driver of the vehicle, to the presence of the cyclist.