ES2717552A2 - System for illuminating road tunnels - Google Patents

Abstract

The invention provides a system for illuminating a target area in a road tunnel (11), which uses a plurality of light-emitting devices (21) secured to the tunnel, said light-emitting devices comprising an LED light source (31) that has electrical power between 0.5-10 W and luminous efficacy greater than 150 lm/W and being arranged so as to project light beams (25) over the target area at a predetermined emission angle AE2, so that same completely illuminate the target area.

Description

DESCRIPTION

Tunnel lighting system for roads

FIELD OF THE INVENTION

The present invention relates to lighting systems for road tunnels and, more particularly, to LED-based lighting systems.

BACKGROUND

The illumination of roads and particularly the sections of tunnels have been studied for many years. The main international body for the drafting of standards and recommendations is the CIE ("International Commission on Illumination").

The fundamental visual problem in a road tunnel is the adaptation of the human eye from the high external luminances during the day, to the low luminances that exist inside the tunnels, taking into account that in a certain distribution of luminances , an obstacle may not be seen if the luminance is much lower than that of the distribution. All this gives rise to the well-known "black hole effect", which prevents drivers from seeing inside the tunnel when they are at a certain distance from the entrance mouth of the tunnel.

The adaptation of the eye to the lighting conditions requires a certain time, therefore, depending on the speed of the track and the length of the tunnel, several areas (threshold, transition, interior and exit) are located inside it. Different levels of lighting depending on the light conditions outside the tunnel.

The installations of normal lighting in tunnels can be summarized basically in two: permanent and reinforcement. Permanent lighting is often called nocturnal and it remains on at all times throughout the tunnel. The reinforcement lighting is turned on by day in the vicinity of the mouths. A much greater lighting reinforcement is required in the entrance mouth than in the exit mouth, since the adaptation of the eye to conditions of greater illumination is faster than adaptation to low lighting conditions.

The lighting of tunnels is an expensive infrastructure not only for its construction but above all for the great electrical consumption that it requires. The permanent lighting is on 24 hours every day and the reinforcement is a very high power that is also being consumed a large number of hours.

The regulations establish the following requirements for facilities:

- Lighting level (luminance) depending on the type of lighting (tunnel area).

- Uniformity of lighting (not only a medium level of adequate lighting is requested, but there are no dark areas and the lighting is uniform (global uniformity) and there is no "blindness" (longitudinal uniformity).

- Distribution that does not make the light points at distances that cause the annoying "flicker" effect (flashing) These distances forbidden for motorway or highway tunnels (speeds around 100 km / h) are between 2 and 12 meters.

Traditionally, tunnel lighting has used sodium vapor lamps for its high luminous efficiency (ratio of luminous flux emitted and electric power consumed [lumens / watt]). These lamps have greater efficiency the greater the power consumed by them.

The design used in the permanent lighting of the tunnels results from a compromise between the use of luminaires with the greatest possible power (to increase efficiency) and the attainment of the minimums established by current regulations at all times in relation to the Uniformity parameters. The use of more powerful luminaires allows to separate more the points of light, however, when separating them in excess there is an annoying "blind" effect on the roadway, even though the design of the reflectors extends the emission angle of the light, the flow received at a certain distance from the projectors ends up being noticeably smaller than under them, if we want to have luminaires with sufficient performance; it must be borne in mind that the installation height of luminaires inside tunnels is usually very low.

Recently, advances in the field of LED technology applied to lighting have provided the possibility of having high efficiency luminaires at increasingly lower prices. In addition, this technology provides important advantages over other existing as regards the duration and consequent saving in maintenance, reduction of depreciation (decrease in performance with operating time) the choice of color temperature and regulation (by drivers that adjust the consumption to the luminous necessities of practically proportional form) At the moment LEDs of luminous effectiveness superiors to 160 lumens / watio are had at low prices.

However, the application of LED technology to the lighting of tunnels has not been imposed as in other fields of application because manufacturers have been limited to manufacture projectors for tunnels similar to the existing ones of sodium vapor only with LEDs. This has not been a great advantage over what already exists, because the most advanced LEDs have a luminous efficiency similar to 400W high pressure sodium vapor lamps. For this reason, most of the studies of change to LEDs have been limited to permanent lighting, where it is possible to achieve a small advantage in luminous efficiency compared to the VSAP (High Pressure Sodium Vapor) projectors of 150 W or 250 W, which are usually distributed at distances between 20 and 30 meters. However, it makes no sense to conduct the study for the reinforcements, and the savings produced in the permanent lighting are so small that it is questionable the return on investment necessary to change the existing VSAP projectors for other LEDs.

An example of this known state of the art is the Chinese patent CN 102374452 which discloses the use of LED projectors of between 80 and 200W, including several tables with the results of luminances obtained with these light sources in the different sections to be considered in the lighting of a tunnel. This document highlights the advantages of the duration of LED lamps compared to other technologies (fluorescent, metal halide, VSAP, etc.), the additional advantages for a better control of the level of illumination depending on the external features and the advantage that it is directional and not scattered sources (bulky lamps that distribute light in all directions). It also means the high color rendering index (CRI) compared to other sources such as sodium vapor lamps. All these circumstances make a tunnel lighting system with LEDs more economically viable and suppose an improvement in security. However, this document does not disclose the essential idea of the present invention, which consists of employing low power light spots distributed at small distances to achieve a uniformity close to 100% and to take better advantage of the directional light characteristics that have the LEDs.

That is, while CN document 102374452 discloses the use of more powerful LED projectors whose use is to replace the current ones of other technologies (mainly high pressure sodium vapor) at similar distances to those currently used. With this technology, the object of the present invention is not to substitute an existing lighting system for another with LED luminaires located in the same points, but to make a totally new system with a continuous distribution of small points of light.

For this, the present invention is based on the use of small LED lights instead of large bulbs to achieve a uniformity close to 100% and take advantage of the possibility that give the LEDs to do this distribution with low power points, and at the same time to direct the light accurately to the road and the environment that is necessary to illuminate (such as shoulders and sidewalks) to the exact extent and without wasting anything.

Unlike what happens in the Chinese patent indicated as known state of the art where only the angle of inclination AI of the projectors is taken into account, in the present invention, in order to achieve a uniformity close to 100%, the emission devices of light are provided with closing lenses that enable a predetermined emission angle AE2 of the light beams.

SUMMARY OF THE INVENTION

The invention provides a lighting system of a target area of a road tunnel, such as a roadway, using a plurality of light emitting devices attached to the tunnel comprising a LED light source of an electrical power between 0.5-10w and a luminous efficiency greater than 150 lum / w and which are arranged to project light beams on the target area with a predetermined emission angle AE2 so as to provide uniform illumination. This means using a much larger number of light emitting devices than the luminaires used in the known systems for the same target area.

In one embodiment, the light emitting devices comprise: a) an electronic control board connected to the led light source and the interface means and attached to a metal base; b) a closure lens configured to achieve a predetermined emission angle AE2 of the light beam; c) a plastic enclosure disposed between the closing lens and the metal base; d) a heat dissipating element attached to said metal base.

The lighting system also comprises interface means between the light emitting devices and an electrical supply network of alternating current to supply them with direct current. These interface means include means for regulating the intensity and / or voltage of the direct current.

The lighting system also comprises means for fixing the light emission devices to the walls or the roof of the road tunnel including means for adjusting the angle of inclination AI of the light beams

In one embodiment, said fixing means comprise, for each light emitting device, an anchoring part in a wall or ceiling of the road tunnel and a receiving frame of the light emitting device which are configured so that the framework The receiver can be located in the anchoring part in the position required to emit a light beam with a predetermined inclination angle AI. In an alternative embodiment, the arrangement of the light points inserted in a longitudinal profile is contemplated.

Other desirable features and advantages of the invention will become apparent from the following detailed description of the invention and the appended claims, in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 schematically shows a section of the light beams emitted by luminaires known in the art in a road tunnel by a plane passing through the central axis of the roadway and by a hypothetical line of alignment of the luminaires in the wall of the tunnel.

Figure 2 shows schematically a section of the light beams emitted by light emitting devices according to the invention in a road tunnel through a plane through the central axis of the road and by a hypothetical line of alignment of the luminaires in the wall of the tunnel.

Figures 3a, 3b and 3c are, respectively, front, rear and top schematic views of an embodiment of the light emitting device according to the invention and Figure 4 is a cross-section of said device illustrating its components.

Figure 5 shows plan, elevation and section views of a receiver frame for the light emitting device of the invention.

Figure 6 shows plan views, elevation and section of an anchoring part of the light emitting device of the invention fixed in said receiving frame.

Figure 7 shows plan and elevation views of an alternative way of arranging the light points inserted in a longitudinal profile.

DETAILED DESCRIPTION OF THE INVENTION

In the present invention, the quality criteria used to characterize the different kinds of lighting are those defined below:

Luminance: Measures luminous intensity per unit area and is expressed in Candelas (cd) per square meter. Applied to road design, the luminance gives an idea of the brightness or degree of reflection of the light incident on the firm. A high degree of reflection can cause discomfort to the driver and prevent him from clearly distinguishing objects that approach the vehicle. The CIE (International Commission on Lighting) recommends luminance values around 2cd / m2 on motorways and highways, and around 0.5-1 cd / m2 in urban areas.

Overall Uniformity of Luminances (Uo): Relationship between the minimum luminance and the average surface of the roadway. The global uniformity of luminance (U0) is required by regulations that is higher than 0.4.

Longitudinal uniformity of luminances (UL): Ratio between the minimum and maximum luminance in the same longitudinal axis of the traffic lanes of the road, adopting the lowest value of all of them. This is a good indicator of the visual comfort of the driver. Current regulations require that it be higher than 0.4 or higher than 0.7 depending on the importance of the road.

Illuminance: is the amount of light that affects a certain object. Its unit is the Lux, which is expressed in lumens per square meter

Average uniformity of illuminances (Um): Relationship between the minimum illuminance and the average surface of the roadway.

General uniformity of illuminances (Ug): Relationship between the minimum and maximum illuminance of the surface of the road

As indicated, in a known road tunnel lighting system (see Figure 1), luminaires 12 (either VSAP type or LED technology) are used to illuminate a road 13 of a road tunnel 11 that emit light beams 24 with an emission angle AE1 of a magnitude which, although it implies losses of luminous flux at its edges, is considered justified from an energy efficiency point of view.

In the tunnel lighting system according to the invention (see Figure 2), light emitting devices 21 are used to illuminate a road 13 of a road tunnel 11 that emit light beams 25 with an emission angle AE2 of a magnitude that eliminates the losses of luminous flux in its edges to achieve maximum uniformity in the illumination of the roadway and that, in turn, are energy efficient (it must be taken into account that, for graphic needs, the magnitude of the angles AE1 and AE2 in Figures 1 and 2 it can not be considered representative of its real magnitude).

This result is achieved by using light emitting devices 21 of LED technology with an electric power comprised between 0.5 and 10W and with a luminous efficiency greater than 150 lum / W. In this way, its luminous flux will be in the range of between 75 and 1500 lumens. This implies using a number of light emitting devices 21 far superior to that of the luminaires 12 of the prior art for the same length of a road tunnel 11. The available LEDs have reached the energy efficiency of sodium vapor lamps and in addition, its efficiency is higher at low power levels, unlike what happens in sodium vapor lamps.

In the tests carried out, tests have been carried out with different arrangements of the light emitting devices 21. In particular, tests have been carried out in

Unilateral arrangement of the luminaires: in this type of arrangement the luminaires are arranged only on one of the margins of the track.

Paired arrangement of the luminaires: in this case the luminaires are placed facing each other, one on each side of the track.

In the tests carried out, the illumination (or luminance) (luxes) that reach the roadway was measured (using a luxometer as measuring equipment) and theoretical calculations were made with other light distributions that do not improve this luminance but illuminance or the light that after bouncing on the road reaches the driver's eye (candelas / m2 of road)

In the first test conducted, a driver was used that fed 96 points of light of 1.8W each, with an interdistance between the light points of 0.5 meters. The total driver consumption included was 180W to illuminate a 3.5 meter wide lane in a unilateral arrangement. The result was 106 lux of medium illumination. This replaced two 150W VSAP projectors 24 meters apart. The test was done in a unidirectional two-lane tunnel,

In the second test, the arrangement of the points of light was bilateral. In this case, two opposed 180W drivers were used, each one feeding the drivers with 96 light points of 1.8W each. The existing VSAP system was also bilateral, that is, a total of 4 150W projectors were replaced (two in the right lane and two in the left lane) separated by 24 meters.

The points of light used in both tests were high performance LEDs with a luminous efficiency of 157 lum / w (Model NF2X757G-V1F1) and also experimented with prototypes of 187 lum / w (Model NVSL219C).

It is important to mean in relation to this last point that, while the effectiveness in VSAP increases with the power, with LEDs it does not vary, in fact, it increases when the power decreases as the operating temperature decreases and the performance improves.

In both tests, an illumination level higher than 50% was obtained for the existing system of VSAP projectors with a 37% lower power consumption. In addition, the longitudinal uniformity was close to 100% or 1.

We can conclude therefore that, as a reference value of the tests carried out (both unilateral and bilateral) with 180W, it is possible to illuminate 3.5x48 meters (168 m2) with an average level of 106 luxes: 0.0035 lux / m2 / W, which is well above the standards of the technologies based on projectors known in the state of the art. For example, in a single-lane tunnel it was placed in bilateral every 1 meter, the result in medium illumination would be the same as in one-sided every 0.5 meters, because the lighting that reaches the road from the different points of light it simply adds up. Conclusion: 0.0035 lux / m2 / W would be the reference value.

In a third trial, we experimented modifying the interdistance between the points of light, being able to verify that if instead of placing them every 0.5 meters are placed every 1 meter, the level of illumination (luxes) falls just half.

On the other hand it was also experimentally proved that by increasing the interdistance (if the closing lens is not modified by modifying the emission angle AE2) there comes a time when the light emission angles of different points no longer overlap, the uniformity, until reaching a point where if the light of one point does not overlap with the next one, a total shadow is produced in the middle (0 luxes).

In another trial, it was intended to approach the limit of the Flicker (which is approximately 1.8 meters for 100 km / h) instead of distributing both the points of light. In this case, the experiment was carried out on a unidirectional two-lane tunnel. The objective was to verify if with an adequate optics all the light sources could be placed in the tray of the right gable and to save in wiring and communications equipment for the control of the drivers. The problem of using optics (closure lenses) that have to scatter light at a large emission angle AE2 is that losses occur. By separating the points of light more distance and putting them all in a gable is reduced performance, but for a tunnel of only two lanes, this could be affordable saving on material and labor (and then in operation because you have to make half of lane cuts for maintenance ).

In the tests carried out, it was experimented with light sources of different electric powers in the range 0.5 to 10 W and with interdistance of 0.5, 1.0, 1.5 and 1.8 meters. The results obtained were also satisfactory in the sense that although a reduction in light characteristics was detected (a small reduction in uniformity), in any case the values obtained in all the tests were still very high (the linear always exceeded 0, 9 and the global 0.5). However, the economic savings are very large. Obviously, the points of light in this arrangement are more powerful;

In the aforementioned tests, we have worked with what is considered a preferred embodiment in which the electrical power of the LED light sources (31) ranges between 0.5 and 10W, for distances between 0.5 and 1.5m approximately. Obviously, any expert in the field can deduce that if the distance between the points of light increases above the value of 1.5m, for the same luminous efficiency of the LEDs, it would be necessary to resort to higher power devices to achieve greater uniformity, being able in some cases to exceed the preferred values lower than 10W.

As shown in Figures 3a-3c, the light emitting device 21 is powered by cables 29 connected in turn to interface devices (not shown) with a public alternating current network that supplies an electric current to it. it continues with the intensity and voltage necessary to power the light emitting device 21. These power sources can be sources of adjustable type in which the voltage and output intensity can be varied so that the light emitting device 21 can give more or less luminous flux depending on the electrical energy consumed. The relationship between both magnitudes is practically proportional. These power supplies usually have a pair of connectors or cables that receive a command signal 0-10 Vdc, depending on which they carry out the aforementioned regulation.

In the embodiment illustrated in Figure 4, the light emitting device 21 comprises a led light source 31, which may be formed by one or more LED modules, which internally may be composed of a matrix of small LEDs, an electronic plate of control 33 (preferably a metal core plate for better heat removal) to which the LED light source 31 and the power supply cables (not shown in Figure 4) are welded, a plastic casing 39, a lens closure 37 for transmitting the largest amount of received light without producing light losses, a base 35 of, preferably, aluminum to which is attached with screws a heat sink 40 structured in the form of a plate with a plurality of fins projecting therefrom and made, preferably, in aluminum.

In one embodiment, the closure lens 37 is made of polycarbonate with a series of cut grooves that make the Fresnel lens function directing the light with the desired emission angle AE2.

As for the optics, one embodiment of the present invention contemplates the use of counterflow optics (direct the light towards the driver, in addition to distributing it for the entire section of the road). If all the light is sent backwards with the right angle, the luminance that reaches the conductor (this is the backflow) is improved, although a glare effect can be produced, a value that must be calculated so as not to exceed the values established in the regulations. In this way the electrical consumption is greatly reduced since for the same luminous flux of the points of light, the luminous intensity reaches the conductors (candelas per road surface in which the light is reflected). Use small points of light implies that these optics are small and economical.

Backflow involves lenses that scatter light at a large angle and this causes losses. In some diffusers pavements (nothing specular) hardly gain luminance in the observer and the illuminance on the road is penalized enormously, producing great losses in the lenses. Therefore, a precise adjustment of the AI and AE2 angles for each type of concrete pavement is essential and calculate what increases the luminance and what is lost with the lenses. The element of the light emitting device (21) which directs the light with the desired distribution is the closing lens (37). Logically this lens has to be designed based on the led (31) that is chosen, since each led will have a distribution of light that will then be corrected with the closing lens.

Another improvement of the present invention consists in using optics that direct the light so that the surface of the luminaire from which the light comes out never has a projection in the transverse plane pointing to the entrance mouth. This is because the passage of the vehicles generates a soot that is deposited on these surfaces and soiling them in a short time. However, in planes transverse to the section of the tunnel, the deposition of soot is minimal.

As regards the means for installing the light emitting devices 21 in the side walls of the road tunnel 11 (or in other places, depending on the needs) the system of the invention comprises, on the one hand, a receiving frame 41 of the light emitting device 21 (see Figure 5) and an anchor piece 51 (see Figure 6) intended to be located on a wall or ceiling of the tunnel directly or indirectly through another element such as a cable tray.

The light emitting device 21 is fixed to the receiving frame 41 (by, for example, screws applied to the holes provided for that purpose in both elements) and the receiving frame 41 is installed in the anchoring part 51 in the appropriate angular position within of the angular box 53 (using a suitable fixing accessory) to emit the light beam with the appropriate inclination angle AI (see Figures 1 and 2).

In an alternative installation mode shown in Figure 7, it has been considered to replace the use of a plurality of small isolated point light spots by that of numerous points of light inserted in a longitudinal profile. This configuration, which can also be unilateral or bilateral fixed to the gables or cable trays, or can be placed on the key on each lane or to illuminate several lanes, has the advantage that you do not have to approach the limit of the Flicker, but only high performance LEDs have to be found and placed at the necessary distance depending on the geometry of the tunnel. Although the additional cost of the profile has to be addressed, it saves on installation labor. As any skilled person will understand, the power of the profile section will depend on its length. The figure shows a section of a longitudinal profile 61 on which several light emitting devices 21 have been inserted. The reference "Id" refers to the distance to which the light emission points can be placed, which will be variable , in accordance with the present invention in a range from somewhat less than 0.1 m to values close to 1.8 m (remember that the limit of the Flicker is 1.8 m for 100 km / h). reference to the closing lens similar to that used in the individual light points.

By way of indication it should be noted that a light emitting device 21 can have dimensions of 30x40 mm and a weight of 30 grams, although there is no limitation in this regard.

As explained above, the adaptation of the eye to light conditions requires a certain time, therefore, depending on the speed of the track and the length of the tunnel, several zones are located inside it (threshold, transition, interior and exit) that require different levels of lighting depending on the light conditions outside the tunnel. Thus, Figure 8 reproduces the level of illumination in the different areas of a tunnel that is contemplated in the ICD 88: 2004 standard (Guide for the lighting of road tunnels and underpasses).

A first application of the object of the present invention on the basis of a plurality of uniformly distributed small light emission devices 21 was intended for permanent lighting in the inner section, where the level of illumination required is very low and hence arose the problem when using VSAP projectors necessarily of enough power. VSAP lamps are also more effective the higher their power. In the circuits intended for reinforcement lighting (mainly in the entrance mouth) the level of illumination required is so high that traditional VSAP projectors (or the LED equivalents that substitute them) are adequate and are placed at small distances. However, in the second part of the threshold zone and in the transition zone (as defined in the representation of the level of illumination in the different zones of a tunnel of Figure 8) the minimum level is a continuous curve and the The usual technique is to use steps that provide a level of illumination superior to that of the aforementioned curve. With a distribution of small light emitting devices 21 as described in the present invention, the distribution of light emitted with that prescribed in said curve can be adjusted with total accuracy, with the consequent energy saving. In addition, the control system can adapt with total precision the conditions of interior lighting to those of the outside of the tunnel, being always adjusted to the level established by the curve of the ICD 88: 2004.

Taking into account the current regulations, it can be said that everything depends on the L20 (the luminance on the outside that in turn determines the luminance in the threshold zone) and this is different in each tunnel and in each mouth. As indicated above, as a result of the experimental phase carried out it was possible to conclude that with a separation of 0.5 m 0.0035 lux / m2 / W is achieved, so if the interdistance is decreased up to, for example, 0 , 1 m, this value would be multiplied by 5. Therefore, as what is being installed are very small points of light, by varying the interdistance or separation between them or with the arrangement of elements of greater power or arranged in parallel, is It is possible to adapt to the CIE 88: 2004 curve with great precision, achieving significant energy savings.

Therefore, by way of summary, we can point out that among the advantages of the invention are the following:

A precise adjustment of the luminous flux emitted to the area to be illuminated is achieved with the consequent reduction of electrical consumption. By using light emitting devices 21 of small magnitude, the emitted light can be directed to the target area with absolute precision without emitting anything at all to other areas that it is not necessary to illuminate (such as ceiling or walls in the case of devices intended to illuminate only the road).

Uniformity close to 100%. The juxtaposition in the roadway of the light beams emitted by the light emitting devices 21, which are separated at very close distance as a result of their low power, generates a homogeneous illuminance in the road and a luminance equally homogeneous to the driver, with the consequent sense of comfort. The parameters of uniformity that are achieved are close to 100%.

Cost reduction. The mass production of the light emitting devices 21 (which may be the size of a matchbox) involves a significant reduction in costs compared to other alternatives. The increase in the cost of installation labor associated with a greater number of elements is much lower than the savings in production costs.

Increase in the efficiency and duration of the LEDs. The insertion of numerous LEDs in a single assembly inside the housing of a large luminaire generates a significant problem of heat dissipation. The luminous efficiency of the LEDs and the number of hours of life of the same diminish drastically when making them work at high temperatures. This means that high-power LED luminaires require complex heat dissipation radiators, and even the use of forced ventilation systems, with the consequent increase in production costs and electricity losses. The use of electronic elements of small size reduces the heat generation, the temperature of the equipment and greatly facilitates the dissipation of heat to the air, being able to avoid the dissipaters, or using simple, small and economical aluminum dissipators.

Although the present invention has been described in connection with various embodiments, it should be understood from the foregoing that combinations of elements, variations or improvements can be made that are within the scope of the invention as defined in the appended claims.

Claims (11)

A lighting system of a target area of a road tunnel (11) comprising a plurality of light emitting devices (21) attached to it, wherein the spacing between the light emitting devices (21) can adopt any value in the range from 0 m to 2.0 m, characterized in that said light emitting devices (21) comprise: - a LED light source (31) with an electric power between 0.5-10w and a luminous efficiency of more than 150 lum / w; - a closure lens (37) configured to achieve a predetermined emission angle AE2 of the light beams (25) ;. - means for fixing the light emitting devices (21) to the walls or the roof of the road tunnel (11) provided with means for adjusting its inclination angle AI; so that by adjusting the angles AI and AE2 the target area is completely illuminated with a longitudinal uniformity greater than 90%. System according to claim 1, wherein: - said target area is a carriageway (13) or a part thereof; - the light emission devices (21) are fixed to the walls or the roof of the road tunnel (11). System according to any one of claims 1 to 2, which also comprises interface means between the light emitting devices (21) and an electrical network for supplying alternating current including means for supplying direct current to said emitting devices. of light (21). System according to claim 3, wherein said interface means also comprise means for regulating the intensity and / or voltage of the direct current supplied to the light emitting devices (21). System according to any of claims 1-4, characterized in that the light emitting devices (21) comprise: - an electronic control board (33) connected to said LED light source (31) and to said interface means and joined to a metal base (35); - a plastic enclosure (39) disposed between the closing lens (37) and the metal base (35); - a heat dissipating element (40) attached to said metallic base (35). System according to claim 5, wherein said metal base (35) and said heat dissipating element (40) are made of aluminum. System according to any one of claims 2-6, characterized in that said fixing means comprise for each light emitting device (21) an anchoring part (51) on a wall or on the roof of the road tunnel (11). ) and a receiving frame (41) of the light emitting device (21) which are configured so that the receiving frame (41) can be located in the anchoring part (51) in the position required to emit a light beam (25). ) with a predetermined angle of inclination AI. The system of claim 7, wherein the anchoring part (51) comprises an angular recess (53) configured to allow a light emitting device (21) attached to a receiver frame (41) to be located in the Anchor piece (51) in different angular positions with respect to the road. System according to any one of claims 2-6, characterized in that the means for fixing the light emission devices (21) to the walls or the roof of the road tunnel (11) comprise a longitudinal profile 61 on which a plurality of light emitting devices 21 have been inserted at a variable "Id" inter-distance. System according to any one of the preceding claims, in which optics are used to direct the light so that the surface of the light emitting device (21) through which the light exits never has a projection in the plane perpendicular to the direction of circulation of vehicles. System according to any one of the preceding claims, in which the fixation of the light emitting devices (21) is made according to a counterflow optic by directing the light towards the entrance mouth of the tunnel.