It is known about the presence on the market of a colored sign band made of plastic. Said band consists of a film with a thickness of about 0.1–1.5 mm, a height of few centimeters to a maximum of 10 cm, and a length varying from 10 to 200 meters according to its application.
This kind of sign band is commonly colored on both surfaces. The coloring is normally carried out by alternating white-colored areas with red-colored areas. Such areas are placed transversally with respect to the longitudinal development of the band, thus producing a peculiar two-color effect.
A sign band as described above is used by workers in the road field to indicate to other people the presence of an obstacle or to signal the presence of a dangerous situation. Such bands are normally used for road signs of various kinds, for instance along a roadway or to delimit and circumscribe a given area near which there is an obstacle or a danger, such as is the case for road works.
A sign band of the kind described above fully performs its function as a signaling device according to the visibility in the area between the beholder's position and the position of the two-color band.
In practice, the kind of two-color sign band available on the market is broadly used, in particular for night signs. However, the sign band belonging to the state of the art is not without disadvantages.
An important disadvantage consists in that a vehicle driver, for instance a car driver, can perceive the presence of a sign band placed in the direction of his/her visual field at a distance which can vary according to the visibility in the area between the vehicle driver and the sign band. That is why the distance at which a car driver perceives the presence of a sign gets shorter if visibility decreases or if the light surrounding him/her gets weaker. Particular conditions of insufficient visibility can also occur in the hours between dawn and sunset.
Several car drivers know that in case of weather conditions such as rain, fog and snow visibility along the driving direction can be highly reduced also at night. In such circumstances visibility can be difficult and many car drivers can find it hard to see before them a sign indicated by means of a simple two-color sign band at the state of the art.
In particular, a two-color road sign as described above can be hardly used and useful if placed along a roadway at night. All vehicle drivers indeed know that at night visibility on a roadway can be unsuitable to allow a driver to see an obstacle at a such a distance as to avoid it. As a matter of fact, the two-color sign band is used together with other lighting devices such as light source lamps.
A further disadvantage consists in that, when a sign band in red and white having the features described above is struck by a source of light, for instance “white” light, the rays of light going through the colored band are not reflected towards the source. Moreover, the light component striking the band is not amplified and is not reflected towards the source. In particular, in complete absence of visibility, when a sign band according to the state of the art is struck by a source of “white” light, no component of the incident light is simultaneously absorbed, amplified and reflected towards the source.
For instance a car driver illuminating with the lights of his/her car a two-color sign band will not see any component of reflected light. The absence of reflected light does not allow the car driver to see an obstacle signaled by means of a two-color band at the state of the art in complete absence of visibility. Consequently, the fact that a two-color sign band does not reflect light cannot favor its use for many applications. Therefore, there is the need on the market for a sign band without the disadvantages at the state of the art. In particular, there is the need for a sign band which can be used in any condition of visibility. More in particular, it is important to have a sign band for night and day road signs.