Road signals are clearly visible even at night or in low light conditions because they have a special property: they are retrioriflectsThat is, they are able to postpone a large part of the lights that invests them, but without transforming them into mirrors. This is achieved by applying to road signs special films formed by glass microspheres or micropisms.
How do road signs do to reflect light
Road signals become retrioriflect thanks to the application of specials films on their surface. These films are designed for reflect the light Directly to its source, like the headlights of a car, making the signal clearly visible even at night or in low light conditions.
- Glass microspheres: Some films contain millions of tiny glass spheres. When the light affects these spheres, it is refracted, reflected on the rear surface of the sphere and then refracts again as it comes out, going back towards the light source.
- Micropisms: more modern technologies use micropisms, small three -dimensional pyramid -shaped structures. The light that enters these prisms is reflected internally several times before being redirected to the source. Micropischematic films are generally more efficient in retoriflect the light than those with glass microspheres, appearing brighter and visible from greater distances and wider angles.
The retororiflect films are typically made up of different layers:
- Support layer: provides the basis for plastic wrap.
- Retroriflenting layer: Contains the glass microspheres or micropisms responsible for the retoriflexion.
- Protective layer: protects the retroriflecting layer from atmospheric agents, from wear and out of the bleeding of the color caused by UV rays.
The quality of the retroriflect road signals depends on several factors, such as the dimensions, the shape of the signal, the quality of the materials used, and the corner with which the light affects the signal.
What does the law say on the back signals backward
The law governing the characteristics of the road signals, including their retoriflexion, is mainly New Highway Code (Legislative Decree 30 April 1992, n. 285) and the relative Execution and implementation regulation (Decree of the President of the Republic 16 December 1992, n. 495) and subsequent amendments.
Here are some key points that concern the retoriflexion of road signals:
- Article 39 of the Highway Code (road signs): It establishes that all signals must be perceptible and readable both at night and during the day. Night visibility can be ensured, among other things, with the use of suitable reflective films (term often used as a synonym for retroriflects).
- Article 77 of the execution regulation (general rules on vertical signals): specifies that the retororiflect films used for vertical signals must have colorimetric, photometric, technological and duration characteristics compliant with a technical disciplinary approved by the Ministry of Public Works (now the Ministry of Infrastructure and Transport).
- Technical disciplinary: The Ministry has issued several technical disciplines over the years that define in detail the requirements that retroriflective films must possess in terms of retroriflexion coefficient, colors, duration, resistance to atmospheric agents and other parameters. An important reference is the Ministerial Decree 31 March 1995which approves the technical disciplinary on the methods of determining the quality levels of the retororiflect films used for the construction of road signals.
