Description

The present invention relates to an asphalt structure comprising a surface course or top surface area in which at least one trench comprising two side walls and a bottom side is present, in which trench a housing comprising a U-profile is installed. The present invention further relates to a housing and to the use thereof in a surface, in particular an asphalt structure provided with a trench.

Asphalt has always been used in road construction, but this material has also become the standard in paving construction in areas such as container terminals, airports and port roads exposed to slow-driving, very heavy traffic. Asphalt is a mixture of sand, gravel (or rubble) and a very fine filler bonded together with bitumen, a product from the petroleum industry. Asphalt production plants are capable of imparting various properties to the asphalt by varying the ratio between the various components and the composition thereof. Depending on the application, a liquid-tight asphalt mixture may be used, or a water-permeable, noise-reducing porous asphalt for flexible mixtures or mixtures that are capable of withstanding concentrated, heavy loads.

Bitumen is known to have viscosity and elasticity, in contrast to rigid elastic cement concrete. Elastic material is characterised by its reaction to load. The material deforms under load, being either extended or compressed. Once the load is removed, the material will immediately return to its original shape. In reality, the asphalt behaves in a much more complex manner. Asphalt is viscoelastic, a property which is affected by the working environment. Both the temperature and the degree of loading have an effect on the response of the material. A higher temperature and slow-driving or stationary traffic cause a lower elastic response and stimulate a viscous response, which can result in permanent deformation (rutting). The load from the traffic passing over the pavement leads to stretching and stresses in the pavement. The vertical compressive stress is felt through all the layers, and if the maximum compressive stress of the unbound layer of stone or sand is exceeded, this will lead to permanent deformation thereof. The asphalt layers are also subjected to tensile stresses, which can, in certain conditions, cause lateral displacement, which in turn will result in permanent deformations. Thus, two specific defects occur in asphalt pavements: functional defects (damage to the surface) and structural defects (the pavement is no longer capable of withstanding the load).

Thus, if trenches are to be formed in such an asphalt layer, those trenches will not maintain their original dimensions with the passage of time because of the viscoelastic behaviour thereof.

As a rule, road markings are installed in or on pavements. Roads on which cars, trucks, buses and (motor)bikes, but also other road users, for example pedestrians, travel must meet a number of safety requirements. An important aspect thereof is road marking, for example in the form of lines, stripes and the like. Thus, a multitude of road markings are used, which each represent specific information. Road markings can therefore be regarded as signs on the pavement that guide the traffic through visual information. Road markings or lines are known in many embodiments. A known road marking is for example a continuous line that indicates that the road user must not cross that line. In the case of a broken line beside a continuous line, however, the road user is allowed to overtake from the lane beside the broken line but not from the lane beside the continuous line. Furthermore, so- called sharks' teeth are used, which indicate to road users that they are approaching a priority road. In addition to that, there are diagonally striped sections, which are in fact end of lane markings. On motorways block stripes are sometimes used at places where the traffic can merge and exit. Road markings thus comprise, inter alia, arrows, strips, continuous lines and broken lines, but also sharks' teeth.

In order to make said road marking visible to the user also in the dusk or the dark, a luminescent component or, in some cases, a reflective material such as glass bead is added to the road marking in certain applications, which latter component lights up upon being irradiated, for example by a car's headlights. The drawback of a luminescent component is that after some time the marking cannot be visually perceived any more in dusky or nightly conditions.

The current trend in the car industry is the development of autonomous cars. Such autonomous cars are provided with modern communication means for communication with each other but also for quick and accurate determination of the position of the car and changes therein. It is therefore desirable that pavement over which the autonomous cars pass can exchange information with the autonomous cars. The pavement will to that end be provided with all kinds of communication means. Such communication means must be permanently installed in the pavement, both in existing roads and in roads to be newly constructed.

From International application WO2014-175732 in the name of the present applicant there is known a road marking comprising a profile to be installed in the pavement, in which profile a luminescent component and furthermore one or more light sources are present, which luminescent component is disposed above the one or more light sources, characterised in that the profile is made of an elastic material, wherein the part of the profile present at the surface of the pavement is translucent.

Belgian publication BE 1007825 discloses a uniform holder comprising a metal U-profile which houses an aluminium C-profile, in the upper side of which C-profile openings are provided through which LED lights protrude. The LED lights are embedded in a resin material that transmits LED light, which resin material forms the upper surface of the holder.

British publication GB 266,394 discloses a light line for traffic guidance, which is to be installed in a channel formed in a pavement. The light line is made up of a number of transparent or semi-transparent blocks placed end to end in the channel, each block being provided with a through hole for accommodating the light source. In the channels, the transparent or semi-transparent blocks are separated by intermediate blocks of rubber, which intermediate blocks serve to absorb external forces and which are also provided with a through hole for accommodating the light source.

The object of the present invention is to provide an asphalt structure provided with one or more trenches, in at least one of which trenches a housing is present, which housing is positioned in the visco-elastic asphalt such that the occurrence of damages to the housing and the components contained therein, caused by the visco-elastic behaviour, is restricted to a minimum.

Another object of the present invention is to provide an asphalt structure provided with one or more trenches, in at least one of which trenches a housing is present, which housing has good visibility for the road users and which will not be easily damaged by road traffic passing over the trench.

Yet another object of the present invention is to provide an asphalt structure provided with one or more trenches, which trenches are configured so that they also comprise curves, turnoffs or bends, wherein a housing capable of following such curves, turnoffs or bends is present in at least one trench.

Yet another object of the present invention is to provide an asphalt structure provided with one or more trenches, which trenches contain one or more elements capable of communication with a vehicle passing over the asphalt structure, which elements are accommodated in a housing, which housing is permanently installed in the trench.

The present invention thus relates to an asphalt structure comprising a surface course in which at least one trench comprising two side walls and the bottom side is present, which trench contains a housing, which housing comprises a U-profile, wherein, viewed in the longitudinal direction of said trench, the housing is divided into alternating rigid partitions and flexible partitions.

Using such a housing, the forces exerted by the asphalt on account of the viscoelastic behaviour of the asphalt will be absorbed by the housing. The elements that may be positioned in the housing, for example a light line, will thus not be damaged by said forces. It will be understood that the present invention is by no means limited to the number of trenches or the special geometric shape thereof. In a special embodiment, trenches, grooves, slots, also called notches, may be slightly "round" or convex, in which case the terms "side walls" and "bottom side" as used before do not unequivocally apply. However, such special geometric shapes of the trench also fall within the scope of the present invention. Trenches can be formed in the asphalt in a usual manner, for example by milling, sawing or drilling. It should furthermore be understood that the present invention is in particular suitable for use in asphalt structures. In a special embodiment, the present housing could also be used in a different type of surface, for example in a surface of concrete, cement, or a combination thereof, possibly with asphalt, or paving consisting of concrete elements, paving bricks or clinkers.

In one embodiment of the present asphalt structure, a plastic or synthetic material, in particular a material selected from the group of flexible polymers and thermoplastic materials, is present in the area enclosed by the U- profile. The plastic material in particular functions to fix the elements to be accommodated in the present housing, such as light sources, sensors, electricity cables, communication cables and induction coils, in place in the housing and protect them against external influences. The material of which the present housing is made is a metal, such as iron or aluminium, for example. It is also possible, however, to use a (transparent or semi-transparent) plastic such as epoxy (concrete) or GRP (glass reinforced plastic).

With a view to taking up or absorbing the forces exerted by the asphalt, which may be transmitted by the housing, the space between said trench and the housing is preferably filled with a filling material. Such a filling material can also be used for permanently fixing the element positioned in the housing, for example a light line, in said housing. An example of such a filling material is a flexible resin material, in particular a flexible thermoplastic synthetic resin or a flexible polyurethane. Materials that can be used as a filler in the housing include: a synthetic resin, such as a clear polyurethane or a flexible epoxy. It is desirable in that case that the filling material that is used be translucent so as to make the light that is to be emitted by the light line visible. If, on the other hand, the present housing does not contain a light line but, for example, sensors, electricity cables, communication cables, induction coils, the filling material to be used need not necessarily be translucent.

The embodiment of the housing as a U-profile makes it possible to construct the housing as a so-called prefab element. Any irregularities in the bottom of the trench can be compensated by the housing itself or by the use of a filler or an adhesive.

According to a preferred embodiment, the present asphalt structure is configured so that the space between said trench and said housing is provided with a filler, in particular a filler that provides adhesion between said trench and said housing, in particular a filler of the thermosetting plastic type, for example a two- component curable plastic material. In such a structure, the housing will protect not only any elements present in the housing, selected from the group of light sources, sensors, electricity cables, communication cables, induction coils or combinations thereof, against damage, but also the material provided outside the housing. In addition, upon forming the trenches in the asphalt, the trench that is obtained will usually have a dimension slightly larger than that of the housing to be installed. I n order to prevent the housing being "loose" in the trench, it is desirable that the space between the housing and the trench be filled with a filling material, which material can also be regarded as an adhesive between the housing and the trench. The filler to be used outside the housing, in particular in the space between the trench and the housing, may also be a synthetic resin, viz a polyurethane, an epoxy or an acrylate, the latter being preferred because of its rapid curing. In specific embodiments, a synthetic resin mortar, for example filled with mineral elements such as sand and filler, may be used as a filling material on account of the strength of this material. In specific embodiments it is also possible to use flexible cement mortars.

The present inventors assume that if the rigid partitions of the present housing are actually bonded to the asphalt, an additional mechanism will play a part, viz forces and stresses caused by temperature variations. Because of the viscoelastic nature of asphalt, any length changes resulting from temperature variations will be absorbed in the material itself. After all, a change in temperature would lead to a length change. It is noted in this connection that the temperature expansion coefficient of asphalt is higher than that of concrete. This desired length change causes stress in the material, after all, the asphalt can be regarded as a semi-infinite continuous pavement layer, without expansion joints, and the length of the asphalt must therefore remain unchanged. These stresses relax away into the viscous component of the asphalt and after some time the material will be without stress again and unchanged in length at the new temperature. The rigid material of the present housing explicitly does not comprise a viscous component, because otherwise the present housing will not be able to protect the elements present therein, such as light sources, sensors, electricity cables, communication cables, induction coils or combinations thereof, which one or more elements are in particular placed on or connected to a flexible PCB (printed circuit board) in said housing, against permanent deformation, for example caused by traffic passing thereover. According to the present inventors, the present housing can be regarded as being elastic (such as concrete) and will thus expand and shrink when temperature changes occur: a rigid material requires expansion joints. The present housing to that end comprises flexible partitions between the rigid partitions. In one embodiment it is desirable that the rigid, expanding and shrinking partitions be fixedly connected to the asphalt, which (on balance) does not expand and shrink. It is therefore desirable that no crack be formed in the asphalt at the end of a rigid partition upon shrinkage thereof, for example in the case of a fall in temperature. The present inventors assume that the movements at the end of the partitions must not be greater than the absorbable viscoelastic stretch of the asphalt allows. In one embodiment, the length of a partition is limited to about 20 to 60 times the grain diameter in the asphalt, on average being about 10 mm, wherein the flexible partition/joint must be capable of offsetting this movement. After all, the length of the assembly of rigid and flexible partitions remains unchanged (on balance).

In a special embodiment it is preferable that the housing is divided in its longitudinal direction into alternating rigid and flexible partitions. Such a division is desirable, for example in order to be able to build bends in the asphalt structure. Such a division is also desirable with a view to compensating for temperature variations and the expansion caused by said variations in the materials that are used, without this leading to the housing being "loose" in the asphalt structure. The use of such rigid and flexible partitions makes it possible to build not only straight sections but also curves or turnoffs.

It is for example possible that the length over which said rigid partitions extend in the longitudinal direction of said housing is greater than the length over which said flexible partitions extend. The longer rigid partitions will be used for the "straight" parts of the trench, whilst the flexible partitions are in particular suitable for building bends.

In order to prevent the occurrence of undesirable stresses in the housing itself it is preferable that said flexible partitions are present in all sides of said housing. These undesirable stresses may for example result from temperature variations and the resulting length changes of the rigid partitions of the housing.

Special embodiments of such flexible partitions include a folded or ribbed structure.

The housing may have a fixed length, but it is also possible that said housing is divided in its longitudinal direction into individual U-shaped or box-shaped elements, which U-shaped elements comprise alternating rigid and flexible partitions. Such U-shaped elements are placed one behind another in a trench so as to provide the desired protection for the elements present therein against the viscoelastic behaviour of the asphalt.

From the viewpoint of the road users it is desirable that said housing be installed in said trench in such a manner that the height of said housing is substantially level with the upper surface of said asphalt structure. The housing will thus be recessed in the trench, so that no undesirable ribs or elevations higher than 2 to 3 mm will be formed in the upper surface of the road, which ribs or elevations can lead to undesirable traffic situations, in particular for motorcyclists.

To increase visibility, it is desirable that said housing be provided with luminescent components, in particular if the housing contains one or more light sources, such as a light line. Such luminescent components provide light after being "irradiated", so that the housing with the light line installed therein can emit light of its own also in dark conditions. In one embodiment, such light sources, in combination with any luminescent components that may be provided, are embedded in a resin material. The present housing may also comprise lens elements for directing the light emitted by the light line. The housing may also comprise colour filters.

Examples of a suitable light line include an elongate light element or a ribbon, for example with LEDs, electrically powered in both cases. The light line may be made up of EL, LED, OLED.

The present asphalt structure is thus very suitable for constructing the trench according to an arcuate configuration.

In another embodiment of the present asphalt structure, the trench is configured as a line or a strip, which line or strip is positioned in said asphalt structure for passage of vehicles in random directions thereover. An example of such a line is a halt line at traffic lights, in which line induction loops are installed for controlling traffic lights. But also strips for airports, motorways and ports are to be considered in this regard. Because of the special construction of the housing, the elements present therein, as mentioned before, will not be exposed to undesirable high mechanical forces, so that the functionality of said elements is retained. In other words, the housing provides optimum protection against damage caused by said viscoelastic behaviour, which viscoelastic behaviour will manifest itself in particular at halt lines. At said halt lines, vehicles will exert a mechanical force on the ground surface, in particular the asphalt, as a result of their braking and stopping, causing the asphalt to exert a mechanical force on the housing. This force will occur at intervals all the time, because vehicles will stop all the time near the halt line, in particular at traffic lights.

The present invention further relates to a housing comprising a U- profile, wherein said housing is divided in its longitudinal direction into alternating rigid and flexible partitions. It is in particular desirable that a plastic material be present in the area enclosed by the U-profile, in particular a material selected from the group of flexible polymers and thermoplastic materials. Furthermore it is desirable that the length over which said rigid partitions extend in the longitudinal direction of said housing be greater than the length over which said flexible partitions extend. It is also desirable that said flexible partitions be present in all the sides of said housing. Preferred embodiments of flexible partitions include a folded or ribbed structure.

The invention further relates to a housing which, seen in the longitudinal direction thereof, comprises individual U-shaped or box-shaped elements, which U-shaped elements comprise alternating rigid and flexible partitions. The individual U-shaped elements disposed one behind another of such a housing are preferably separated by a joint. In order to be able to realise an arcuate construction using said housing, it is desirable in specific embodiments that said joint comprise a flexible resin material. An advantageous characteristic of such a flexible resin material is furthermore the fact that it is easily mouldable and capable of filling irregularities in the trench formed in the asphalt structure. The joint can thus be regarded as a "flexible element". In such an embodiment, the rigid parts, in particular the individual U-shaped elements, are interrupted by a joint, which joint is filled with a filler at a later stage. In such an embodiment, the flexible parts are formed simultaneously from the flexible resin upon prefabrication of the assembly of the light line and the U-shaped elements. In fact a "chain" of individual U-shaped elements is thus formed, wherein the individual U-shaped elements are at all times separated from each other by a flexible resin. According to another embodiment, it is also possible to arrange the individual U-shaped elements some distance apart in a trench after the trench has been formed in the asphalt structure, after which a light line, for example, is installed in the individual U-shaped elements. Subsequently, the light line is fixed in place in the individual U-shaped elements by introducing the flexible resin material therein. The flexible resin material will spread in the trench and fill the space between the light line and the individual U-shaped elements as well as the spaces between the individual U-shaped elements and the space between the individual U-shaped elements and the trench. In this way the assembly of light line + individual U-shaped elements is fixed in place in the asphalt pavement.

The housing according to the present invention is in particular provided with at least one light line. The present invention further relates to the use of a housing as described in the foregoing as a (halt) line, over which vehicles can pass in random directions, in an asphalt structure provided with a trench.

The present invention will now be explained with reference to a number of figures, wherein it should be noted that the invention is by no means limited to such special figures.

Figure 1 shows a special embodiment of the present housing.

Figure 2 shows another special embodiment of the present housing.

Figure 3 shows a surface with a housing according to the present invention installed therein.

Figure 4 shows a surface with a housing according to the present invention installed therein.

Figure 5 shows yet another special embodiment of the present housing.

Figure 6 shows a surface with a housing according to the present invention installed therein.

Figure 7 shows yet another special embodiment of the present housing.

Figure 8 shows yet another special embodiment of the present housing.

In figure 1 there is shown a housing 1 comprising two side walls 2, 4 and a bottom side 3. Although the housing 1 is shown to have a rectangular shape in this figure 1 , the walls may also be slightly convex, for example in the shape of a ball (not shown) "cut through" in the middle, with the side walls and the bottom side slightly coinciding. The side walls 2, 4 and the bottom side 3 may also be positioned at an angle different from the one shown herein relative to each other. The side walls 2, 4 may also have different dimensions. Furthermore it is possible that the distance between the side walls 2, 4 as determined by the width of the bottom side 3 is different from that in the illustrated embodiment, for example that the housing 1 has a width smaller than the height of the side walls. The housing 1 shown in figure 1 is divided in its longitudinal direction into alternating rigid partitions 5 and flexible partitions 6. The length over which said rigid partitions 5 extend along the length of said housing 1 is preferably greater than the length over which said flexible partitions 6 extend. From a production point of view it is desirable that the height of the side walls of both the rigid partitions 5 and the flexible partitions 6 be substantially the same, in particular as regards the side walls of a specific side, for example the side indicated at 4. The housing 1 is for example made of a plastic. The rigid partitions 5 may be made of a material different from the material of the flexible partitions 6. The rigid partitions 5 and the flexible partitions 6 may be connected via an adhesive bond, for example using an adhesive, or via a mechanical connection, so as to form a housing. The length of the housing is not limited to a specific dimension. A light line (not shown) can be positioned in the space formed by the side walls 2, 4 and the bottom side 3. In one embodiment, a plastic material (not shown), in particular a material selected from the group of flexible polymers and thermoplastic materials, is present in the area enclosed by the U-profile.

In figure 2 there is shown a special housing 10 comprising two side walls 2, 4 and a bottom side 3. The housing 10 shown in figure 2 is divided in its longitudinal direction into alternating rigid partitions 9 and flexible partitions 8. The length over which said rigid partitions 9 extend along the length of said housing 10 is preferably greater than the length over which said flexible partitions 8 extend. In figure 2, said flexible partitions 8 are represented as a folded or ribbed structure. The housing 10 is for example made of a plastic. The rigid partitions 9 may be made of a material different from the material of the flexible partitions 8. The rigid partitions 9 and the flexible partitions 8 may be connected via an adhesive bond, for example using an adhesive, or via a mechanical connection, so as to form a housing. The length of the housing is not limited to a specific dimension. Although the housing 10 is shown to have a rectangular shape, other geometric embodiments are also possible, as mentioned above in the discussion of figure 1 . A light line (not shown) can be positioned in the space formed by the side walls 2, 4 and the bottom side 3. In one embodiment, a plastic material (not shown), in particular a material selected from the group of flexible polymers and thermoplastic materials, is present in the area enclosed by the U-profile.

Figure 3 shows a front view of a surface in which a housing according to the present invention is installed. The housing 12 is installed in a surface 1 1 provided with a trench having two side walls 16, 23 and a bottom side 17. The housing 12 comprises two side walls 2, 4 and a bottom side 3. The housing 12 is provided with a light line 14 (schematically indicated). The light line 14 is surrounded by a filler 13, in particular a transparent resin, in the housing 12. The filler 13 may further comprise additional components, such as luminescent components, glass beads, pigments, means for scattering or focusing light emitted by the light line and means that add to the skid resistance of the upper surface 21 . The height of the filler 13 in the housing 12 is such that said height is substantially level with the upper surface 21 of the surface 1 1 , in particular asphalt. The space 18 between the housing 12 and the trench is preferably filled with a filler (not shown). The method of installing the housing in the surface comprises forming a trench in the surface, for example by means of a milling operation, placing the housing in the trench thus obtained and subsequently filling the space between the trench and the housing with a filler, if desired. The housing is preferably already provided with the light line and the associated electronics.

Figure 4 shows a front view of a surface in which a housing according to the present invention is installed. The housing 12 is installed in a surface 1 1 provided with a trench having two side walls 16, 23 and a bottom side 17. The housing 12 comprises two side walls 2, 4 and a bottom side 3. The housing 12 is provided with a light line 14 (schematically indicated). The light line 14 is surrounded by a filler 22, in particular a transparent resin, in the housing 12. The filler 22 may further comprise additional components, such as luminescent components, glass beads, pigments, means for scattering or focusing light emitted by the light line and means that add to the skid resistance of the upper surface 21 . The height of the filler 22 in the housing 12 is such that said height is substantially level with the upper surface 21 of the surface 1 1 , in particular asphalt. The space between the housing 12 and the trench, in particular the space between the side walls 2, 4 and the bottom side 3 of the hosing 12 and the side walls 16, 23 and the bottom side 17 of the trench is preferably filled with a filler 19. The method of installing the housing in the surface comprises forming a trench in the surface, for example by means of a milling operation, placing a filler in the trench thus obtained and subsequently placing the housing in the trench containing the filler. When the housing is pressed into the filler, the space between the trench and the housing will fill with filler. The housing is preferably already provided with the light line and the associated electronics.

Figure 5 shows a special housing 50 comprising individual U-shaped elements 51 , each comprising two side walls 2, 4 and a bottom side 3. For the sake of clarity, the housing 50 shown in figure 5 comprises only three successive individual U-shaped elements 51 , but it will be understood that the present invention is not limited to such a number. The housing 50 is thus divided in its longitudinal direction into U-shaped elements 51 separated by a joint, which joint is filled with a flexible filler. Suitable fillers include a flexible resin, viz the resin by means of which the light line is fixed in the housing. In the illustrated embodiment, a "chain" of individual U-shaped elements 51 is in fact formed, which individual U-shaped elements 51 are separated by a flexible resin. The light line that is present in the space defined by the two side walls 2, 4 and the bottom side 3 is not shown for the sake of clarity, and neither are the associated electronics. The trench in which the "chain" of individual U-shaped elements 51 is provided is not shown, either. The U- shaped elements 51 are made of a plastic, for example. The length of the housing is not limited to a specific dimension. Although the housing 50 is shown to have a rectangular shape, other geometric embodiments are also possible, as mentioned in the foregoing in the discussion of figure 1 .

Figure 6 shows a front view of a surface 60 with a housing according to the present invention installed therein. There is a certain analogy between figures 6 and the previously discussed figure 3, but the housing 12 in figure 6 is shown as an "upside-down" U-profile. This "upside-down" configuration means that the two side walls 2, 4 of the housing 12 extend downward, i.e. away from the upper surface 21 . The housing 12 is installed in a surface 1 1 , which is provided with a trench comprising two side walls 16, 23 and a bottom side 17. The "upside-down" configuration in figure 6 is such that the two side walls are more or less supported on the bottom side 17 of the trench. The bottom side 17 may be provided with an adhesive layer (not shown) so as to obtain a good fixation of the housing 12, in particular via the two side walls 2, 4. The housing 12 comprises two side walls 2, 4 and an upper side 3. The housing 12 is provided with a light line 14 (schematically indicated). Because of the presence of the light line 14 in the housing 12 it is desirable that the housing 12 be made of a translucent material. The light line 14 is surrounded by a filler 22, in particular a transparent resin, in the housing 12. The filler 22 may further comprise additional components, such as luminescent components, glass beads, pigments, means for scattering or focusing light emitted by the light line and means that add to the skid resistance of the upper surface 21. The height of the upper side 3 of the housing 12 is such that said height is substantially level with the upper surface 21 of the surface 1 1 , in particular asphalt. The space between the housing 12 and the trench is filled with a filler 13 in figure 6, which filler 13 preferably functions as an adhesive for the housing 12 and the trench. The method of installing the housing in the surface comprises forming a trench in the surface, for example by means of a milling operation, placing the upside-down housing in the trench thus obtained, the housing already being provided with a light line, associated electronics and filler, and subsequently filling the space between the trench and the housing with a filler and allowing the filler to cure or harden. Although the filler 22 does not entirely fill the space of the housing 12 enclosed by the side walls 2, 4 and the side 3 in figure 6, the present embodiment is not limited thereto.

The front view of figure 7 of a surface 70 with a housing according to the present invention installed therein is different from the embodiment shown in figure 6, in particular as regards the positioning of the housing 12 in the trench comprising two side walls 16, 23 and a bottom side 17. The housing 12 in figure 7 is shown as an "upside-down" U-profile. The housing 12 comprises two side walls 2, 4 and an upper side 3. This "upside-down" configuration means that the two side walls 2, 4 of the housing 12 extend downward, i.e. away from the upper surface 21 . The "upside-down" configuration in figure 7 is such that the ends of the two side walls are not in contact with the bottom side 17 of the trench. The height of the upper side 3 of the housing 12 is such that said height is substantially level with the upper surface 21 of the surface 1 1 , in particular asphalt. The method of installing the housing in the surface comprises forming a trench in the surface, for example by means of a milling operation, filling the trench thus obtained with a first amount of filler, then placing the upside-down housing in the filler thus provided, which housing is already provided with a light line, the associated electronics and filler, and subsequently filling the remaining space between the trench and the housing with a filler and allowing the filler to cure or harden. Although the filler 22 does not entirely fill the space of the housing 12 enclosed by the side walls 2, 4 and the side 3 in figure 7, the present embodiment is not limited thereto.

Although mention is made of a light line and any associated electronics in both figure 6 and figure 7, it should be understood that the housing 12 may also contain one or more of sensors, electricity cables, communication cables, induction coils or combinations thereof, usually placed on or connected to a flexible PCB (printed circuit board). If one or more of said elements are present in the housing 12, the material of which the housing is made need not necessarily be translucent. To realise a specific length of the trench in which the present housing as shown in front view in figures 6 and 7 is installed, several individual housings may be positioned one behind another in the trench. By placing such housings one behind another, with a certain gap present between adjacent housings, the filler will fill all the empty spaces between the individual housings, but also the empty spaces between the housings and the trench, both at the two side walls of the trench and possibly also near the bottom side of the trench. Thus a durable structure is obtained in the surface after curing of the liquid filler.

Figure 8 shows yet another special embodiment of the present housing. The housing 80 can be regarded as a so-called prefab construction, wherein the U-profiles, each comprising two side walls 2, 4 and a bottom side 3, are arranged in a row, with a light line 14 positioned near the bottom side 3. In fact, the construction previously discussed with reference to figure 5, in which a housing 50 comprising individual U-shaped elements 51 each comprising two side walls 2, 4 and a bottom side 3 a shown, can be regarded as a "precursor" of the construction shown in figure 8. Although a series of five U-profiles arranged one behind another is shown in figure 8, it should be understood that any number of U-profiles may be used. The light line 14 is enclosed by a filler 81 , which filler is translucent in the embodiment of a light line 14. The filler 81 may further comprise additional components, such as luminescent components, glass beads, pigments, means for scattering or focusing light emitted by the light line and means that add to the skid resistance of the upper surface 21 . Although mention is made of a light line and any associated electronics in figure 8, it should be understood that the U-profile may also contain one or more of sensors, electricity cables, communication cables, induction coils or combinations thereof, usually placed on or connected to a flexible PCB (printed circuit board). The housing 80 is placed in a trench (not shown) and the empty spaces between the inner wall of the trench and the housing 80 placed therein are filled with a filler, which is subsequently allowed to cure. In this way a durable connection between the housing 80 and the trench is obtained. As is apparent from the housing 80 shown in figure 8, the external dimensions of the filler 81 are smaller than those of the side walls 2, 4 on account of the thickness of said side walls. The dimensions is also smaller at the bottom side. Upon placement of the housing 80 in a trench and subsequently filling the same with the still liquid filler, said empty spaces will easily fill, so that a durable connection will form between the housing 80 and the trench all sides of the housing, in particular the other parts of the housing where no U-profile is present.