BACKGROUND OF THE INVENTION
[0001] The invention relates to a detection loop for a road surface, particularly an asphalt
road surface, comprising a carrier with a cable attached thereto in a loop shape,
the cable having one or more electric conductors.
[0002] Such detection loops are generally known and are used for recording the presence
of vehicles driving over such loops. The disruption of the electromagnetic field of
the detection loop caused by the passing vehicles can for instance also be used for
controlling traffic lights, setting speed limits on variable message signs (VMS) and
operating automatic traffic gateways and the like.
[0003] Detection loops are generally disposed after the top layer of the asphalt road surface
has been laid and has cooled off sufficiently. For that purpose slits are milled into
the asphalt into which the cables are laid, which slits are subsequently filled with
bitumen. This method is very time-consuming and detrimental to the quality of the
asphalt. For these reasons methods were looked for to manufacture the detection loops
in advance and attach them to the sub layer of the asphalt prior to the top layer
being applied.
[0004] From
WO00/75906 an electromagnetic traffic signal detection system is known, having one or more detection
loops comprising a pre-shaped electrically conducting material in one or more loops
of a predetermined shape. For installation in a road surface an assembly of a geotextile
base bandage impregnated with bitumen and having electric conductors secured thereon
by a protective tape is placed on a layer (road pavement base) of the road surface.
The assembly is secured to the layer of the road surface by means of a bituminous
strip. After that a bitumen surface layer is applied. It is indicated that this method
can be used at temperatures over 100°C, but temperatures below 80°C are preferred.
[0005] Said known detection loop, that has never actually been used on a large scale, has
a number of drawbacks. First of all it requires a lot of work as the loop consisting
of carrier and cables has to be laid in the correct position and shape, and subsequently
has to be secured to the basis by means of the bituminous strip that is applied over
the loop. Subsequently this method cannot be used with modern asphalt pavers that
work with temperatures of 160-200°C and pressures of 20 tons and more. The sharp-edged
material of the asphalt and the high dynamic loads that arise in applying the asphalt
place particular demands on the protection of the cables, all the more as the caterpillar
tracks of the asphalting machine exert large tensile forces on the cables.
[0006] From
DE 10 327 332 a prefab assembly is known of a netting and a detection loop attached thereto. The
assembly of netting and loop is attached to the foundation layer, for instance by
means of a binder or by attachment elements extending in attachment holes in the netting.
When laying a new road an intermediate layer (Binderschicht) and then a covering layer
is applied over it. The number of loops on the netting can be chosen.
[0007] In this case as well the heat and the forces that arise during applying an asphalt
layer over the loop may result in damage to the conductor and deformation of the loop.
SUMMARY OF THE INVENTION
[0008] It is an object of the invention to provide a vehicle detection device that can be
arranged quickly and easily.
[0009] It is an object of the invention to provide a vehicle detection device having a detection
loop that can easily be laid in the correct shape.
[0010] It is an object of the invention to provide a vehicle detection device having a detection
loop that can reliably be held in the correct shape during transport and during laying.
[0011] It is an object of the invention to provide an arrangement of a road surface having
a vehicle detection device incorporated therein wherein a reliable induction signal
is obtained.
[0012] It is an object of the invention to provide a method with which a detection loop
can reliably and easily be incorporated in an asphalt paving.
[0013] For achieving at least one of these objects, according to one aspect, the invention
provides a vehicle detection device to be accommodated in a road surface, comprising
a cable having at least one electric conductor and a carrier, wherein the carrier
is grid-shaped having elongated grid elements that in between them define grid meshes,
wherein the cable is attached in advance in the desired loop shape on the grid elements
of the carrier, wherein the carrier preferably can be rolled up at least in one direction.
[0014] The cable can be attached to the carrier in advance in an easy and controlled manner
in the desired configuration in protective surroundings, a plant. The grid-shaped
carrier offers sufficient discrete locations to attach the cable including conductor(s)
in the desired configuration. In the preferred embodiment the assembly can subsequently
be rolled up into a compact unit, with the cable on the concave side, and be stored
and transported in said condition that takes up little space. The detection loop is
then protected in the roll. When being placed in the work the grid-shaped carrier,
due to the meshes, further ensures an intense engagement with the road surface layer
to be applied thereon.
[0015] In order to prevent that the electric insulation of the conductor gets damaged as
a result of the high temperatures of hot asphalt and the possibility of short-circuiting,
the cable preferably comprises a heat-resistant insulation. In one embodiment the
electric conductor has a number of singular wires each provided with a heat-resistant
insulation, particularly a heat-resistant coating, particularly lacquer (as known
per se from singular wires in a coil of a transformer), and together form the conductor
in the form of a core/litze wire. In that way a reliable insulation that is resistant
to high temperatures is provided as a whole for the conductor, in the form of a core/litze
wire, preserving sufficient suppleness of the core/litze wire and thus the cable for
laying it in the desired shape and rolling it up. In fact the smallest conductive
element of the cable, the singular wire is provided with a heat-insulating sheath.
The thus coated wires can be stranded into the core/litze wire.
[0016] It is noted that in
WO 99/47894 a detection loop is shown having a cable having a number of multiple-wired or solid
(in order to increase the rigidity) conductors. Each conductor has a coloured insulation
sheath. For protection against heat and damage the group of conductors is enveloped
by a synthetic sheath, preferably of cross-linked polyurethane.
[0017] The cable may comprise several conductors that directly abut one another, particularly
are stranded. The coating of the singular wires in each conductor can provide sufficient
insulation between the conductors one to the other. The several conductors, for instance
seven can be connected in series. In that way a plurality of windings is provided
within the cable. By choosing the number of windings the desired sensitivity of the
detection loop can be set. Furthermore, if not all conductors within the cable are
used, in case of a conductor that is indeed used being damaged it can be replaced
by a conductor that had been free up until then.
[0018] The cable may comprise a sheath with high-strength fibres, such as for instance Kevlar®
to increase the tensile strength. Furthermore the cable can be provided with a layer
of water-blocking material arranged around the conductor or group of conductors.
[0019] In a simple embodiment the cable is attached to the grid elements by means of cable
binders. Such work can be carried out accurately and with ease. The cable binders
may be tie-wraps, preferably having a metal locking strip in the locking end. The
metal locking strip provides a high degree of reliability of the closure under the
arising forces.
[0020] If the locking ends are situated vertically adjacent to the cable and the tie-wraps
have been cut off outside of the locking ends, the height of the device can be kept
limited, which is advantageous when the device comes to lie directly underneath the
covering layer of the road surface.
[0021] The material for the carrier preferably is a material used as reinforcement of asphalt
road surfaces, as for instance known from European patent
0 318 707. As a result of its open structure and the suitable impregnation this grid material
has the advantage of not being detrimental to the quality of the road surface, particularly
as regards the adhesion between the top layer and the sub layer. This is particularly
important as in this way the carrier is able to cover a large surface area. Reference
can also be made to European patent application
0.199.827,
US patent 5.393.559 and
US patent 8.038.364 the contents of which should be considered inserted herein. In one embodiment according
to the invention the grid elements are made of continuous fibres, particularly glass
fibres (such as glass silk), and have either been impregnated or coated, particularly
with a material that is compatible and particularly connectable with the asphalt of
the road surface layers, particularly an asphaltic resin or an asphaltic resin containing
material. A suitable grid is Glassgrid® having a 1 x 1 cm mesh width, preferably 2.5
x 2.5 cm (type 8550).
[0022] The grid elements may form an open fabric with each other, wherein the grid elements
comprise a group of first grid elements and a group of second grid elements that are
perpendicular to the first grid elements, wherein in one embodiment, at the location
of the intersections the second grid elements engage the first grid elements in an
adhering manner at the upper side and lower side thereof for securing the intersection
in the direction of the second grid elements. In that way the height of the carrier
can remain limited, while preserving sufficient strength. In the second grid elements
the continuous fibres can be slightly twined. In the first grid elements the continuous
fibres can be parallel to each other. The flatness of the carrier can furthermore
be kept limited if the first grid elements of the first group are flat-strip-shaped.
[0023] In one embodiment the device is rolled up, preferably with the loop on the concave
side of the carrier. The first grid elements can extend parallel to the axis of the
roll. This may be advantageous in case the carrier is rolled out in the work in the
direction of the roadway. The connections at the location of the second grid elements
extending over and under the first grid elements are able to resist the shearing forces
caused by the material driving over the grid, so that the meshes of the grid can remain
substantially intact.
[0024] The loop can be substantially rectangular with long sides and short sides, wherein
the second grid elements extend in the direction of the long sides.
[0025] At the lower side, the grid elements can be provided with an adhesive that adheres
to an asphalt surface and preferably is pressure-activated. In that way the grid can
easily be stored and transported in rolled up condition, and easily be arranged.
[0026] Ease of placement is enhanced if the grid-shaped carrier can be bent out of its plane,
particularly can be rolled up, in a second direction perpendicular to the first direction.
[0027] For connection of the loop to the loop coupling box, the cable will usually be provided
with connecting sections. In that case it will be advantageous if the carrier has
a main portion for carrying the loop and a part projecting therefrom, forming one
unity with the main portion and to which a part of the connecting sections that connects
to the loop is attached. The connecting sections are then kept in place in the road
surface by the carrier that is already present for the loop. In that way installation
becomes simpler and more reliable. The part of the connecting sections attached to
the carrier may have a length of one or more dm, for instance to span the distance
between the loop and the road side.
[0028] In case the loop is elongated the projecting part of the carrier can project in a
direction transverse to the longitudinal direction of the loop.
[0029] In an alternative description, when the cable comprises connecting sections for connection
of the loop to a loop coupling box, the loop can be attached to the carrier together
with a part of the connecting sections that connect to the loop.
[0030] The connecting sections may extend with a portion to beyond the carrier and at that
location preferably be rolled up.
[0031] On one and the same carrier several cables can be attached in loops situated adjacent
to each other.
[0032] According to a further aspect the invention provides a method for disposing a detection
loop device for vehicles according to the invention in a road surface, wherein the
device in rolled up condition, with particularly the cable on the concave side of
the rolled up carrier, is supplied to the work, rolled out on a basis surface, adhered
thereto and subsequently an asphalt layer is applied. In one embodiment the device
is adhered to the top surface of an asphalt-containing intermediate layer or sub layer.
In one embodiment the asphalt layer is the top layer or covering layer of the paving
in question so that the loop sits relatively high in the road surface which is advantageous
to the signal strength and repairs to the loop.
[0033] In a simple embodiment the device is adhered to the basis surface by means of a pressure-sensitive
adhesive applied thereon.
[0034] The roll can be rolled out in roadway direction of the traffic that will be using
the road surface.
[0035] According to a further aspect the invention provides a road surface provided with
a vehicle detection device according to the invention.
[0036] According to a further aspect the invention provides a traffic system, such as a
system including traffic lights, comprising a road surface according to the invention.
[0037] The particular construction of the cable itself renders it resistant to the high
temperatures and large dynamic forces that arise during applying the top layer, whereas
the grid-shaped flexible carrier serves for easily placing the detection loop on the
base and for its fixation during applying the top layer. As the cable has multiple
cores it is easily possible to vary the number of windings of the loop, so that the
sensitivity of the detection loop can be increased.
[0038] According to a further aspect the invention provides a cable, particularly to be
used as detection loop in a road surface for vehicles, wherein the conductor has a
number of singular wires each provided with a heat-resistant coating, particularly
lacquer, and together forming a core or litze wire, wherein preferably the singular
wires have been stranded into the conductor. In one embodiment only the singular wires
are provided with the heat-resistant coating, particularly lacquer, wherein preferably
the cable comprises several conductors that directly abut each other, particularly
have been stranded. The cable may comprises a number, preferably seven electric conductors
that can be connected in series. The coated singular wires may be wires used for electromagnetic
coils, such as enamelled copper wire. The heat-resistant coating may also be ceramic.
[0039] According to a further aspect the invention provides a detection loop for a road
surface, particularly an asphalt road surface, comprising a strip-shaped carrier with
an electric conductor attached thereto, which have been put in the desired loop shape
in advance and are suitable to be attached to a sub layer of the road surface, before
the top layer of the road surface is disposed over it, wherein the conductor is attached
to the carrier in advance in the desired configuration, which carrier is formed by
a strip of open fabric impregnated with a resin, and the conductor consists of a multiple
core cable, which on the outer circumference is provided with a sheath able to absorb
high temperatures and high tensile forces, and each core is provided with its own
ceramic insulation so that a loop of several windings can be formed.
[0040] The aspects and measures described in this description and the claims of the application
and/or shown in the drawings of this application may where possible also be used individually.
Said individual aspects may be the subject of divisional patent applications relating
thereto. This particularly applies to the measures and aspects that are described
per se in the sub claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] The invention will be elucidated below on the basis of an exemplary embodiment shown
in the attached drawings, in which:
Figure 1 shows a top view of a grid-shaped carrier for a device according to the invention;
Figures 1A and 1B show a detail IA of figure 1 and a cross-section IB of figure 1,
respectively;
Figure 2 shows a top view of a device according to the invention with the carrier
of figure 1;
Figure 2A shows a detail of the attachment of a cable to the carrier in the device
of figure 2;
Figure 3 shows an end of the cable in the device of figure 2;
Figures 3A and 3B show details of the cable end of figure 3;
Figures 4A-D show a few steps in a method according to the invention in the installation
of the device in a road surface;
Figures 5 and 5A show a top view of an arrangement of an assembly of a number of joined
devices according to the invention and a single device therein, respectively;
Figure 6 shows a top view of another arrangement of a number of devices according
to the invention; and
Figure 7 shows a top view of yet another arrangement of a number of devices according
to the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0042] In figure 1 a grid-shaped carrier 1 is shown, composed of first grid elements 2 and
second grid elements 3 that are perpendicular to each other and in between them define
square meshes. In this example the grid elements 2 and 3 are made of glass fibre filaments
and have been impregnated/coated with an asphalt layer/asphaltic resin which is suitable
in view of installation in asphalt layers. The first grid elements 2 are flat, the
second grid elements 3 extend over and underneath the first grid elements 3, see figure
1 B, in which for reasons of clarity this is shown schematically. On the carrier lower
side of the grid elements 2, 3 a layer of pressure-sensitive glue has been applied.
In this example the mesh width of the grid 1 is 2.5 cm. An example of such a grid
is GlasGrid® 8550 by Adfors St Gobain.
[0043] In figure 2, on its upper side, the carrier 1 is provided with a detection loop 5,
which is formed by a cable 6 attached to the carrier 1 by means of cable binders 8,
which as can be seen in the schematic depiction of figure 2A, have been arranged around
the cable 6 and a grid element 2 and/or 3, for instance every 10 cm. The cut-off end
8b projects as little as possible from its locking end 8a. The cable binders can be
TY-RAP® TYB 24MX. The locking end 8a sits adjacent to the cable 6 so that the height
of the carrier with cable remains limited and is not significantly increased by the
cable binders.
[0044] The cable 6 comprises a composed sheath 11, for instance having a TPR outer layer,
a Kevlar sleeving and an XLPE inner layer. Said sheath 11 is also resistant to high
temperatures. Within the sheath 11 a helically wound strip 12 is situated of material
that swells under the influence of water in order to block migration of water in cable
direction. Within the sleeving 12 thus formed there are a number of conductors or
cores 13, in this example seven, see figure 3A, each consisting of a number of -for
instance 16-stranded singular wires 14 of copper, each surrounded by a heat-resistant
coating 15, see figure 3B. The singular wires may have a 0.2 mm diameter. The cable
may have a diameter of approximately 6 mm, the cores 13 may have a cross-sectional
surface of for instance 0.5 to 0.9 mm
2, for instance 0.5 mm
2. The heat-resistant coating, having a thickness of for instance 10-12 micron, on
the singular wires may be a lacquer that has been hardened on the singular wires in
an oven. Such a lacquer is known per se from singular wires in transformer coils,
such as for round lacquered copper coil wire, heat class 200°C. Also see the so-called
enamelled (copper) wire. The singular wires and the cores/litze wires stranded therefrom
remain sufficiently bendable despite the lacquer. It can be permitted here that at
bending of the cable the cores/litze wires or the singular wires slide along each
other without the insulation between the cores/litze wires getting noticeably damaged.
[0045] The cable 6 is attached to the carrier 1 in the plant, wherein terminals 7a,b are
disposed on the entry/exit parts of the cable 6, the so-called loop supply cables
or connecting sections 9', 9". The connecting sections 9',9" may have a length adjusted
to the work in question, for connection to a loop coupling box, for instance several
meters and subsequently have been rolled up in the plant. The device 10 thus obtained
- with the loop on the concave side- can be rolled up in direction X, with the axis
of the roll in direction Y, and then be stored, and also be transported to the work
in that condition. The carrier 1 can also be rolled up in direction Y. The carrier
1 can be rolled up onto itself (particularly in case of larger lengths) or on a piece
of tubing (particularly in case of smaller lengths).
[0046] On site of the work, see figure 4A, the roll 110 of device 10 is wound off in direction
X, parallel to grid elements 3, on the top surface 21a of an asphalt (intermediate
or sub) layer 21 of for instance that sits on a foundation 20. The asphalt layer 21
may be part of a newly to be laid road surface or be part of an existing road surface,
in which case the top layer situated above it and possibly also a part of the asphalt
layer situated underneath it will have been milled away. When the device 10 is situated
at the correct location and in the correct orientation, the pressure-sensitive adhesive
4 is activated (schematically shown with a slight hatching) by means of a roller 120
moved in direction X, so that the carrier 1 is firmly adhered to surface 21 a. In
this way the detection loop is fixedly located at once, in the desired configuration
and cannot -inadvertently- be changed in shape by passing equipment.
[0047] A sticky adhesive layer is subsequently applied over the asphalt (concrete) layer
21 and over the device 1, after which by means of an asphalt paver 130 the asphalt
top layer 22 of the road surface is laid, see figure 4C. The paver 130 then moves
in direction X, parallel to the grid elements 3. The road surface 100 with drive surface
22a, figure 4D, is now ready and the connecting sections 9',9" can be connected to
a connection box, not shown, by means of terminals 7a,b. The grid-shaped carrier 1
here ensures for the dimensional stability of the loop, and also provides local reinforcement
of the asphalt.
[0048] The combination of smaller diameter of the cores and the heat-resistant coating,
particularly lacquer, of the thinnest conductive parts, the singular wires, with the
selected materials render the cable particularly suitable for use as detection loop,
particularly directly underneath a top layer in the road surface. Due to the high
position a (highly) reliable signal can be obtained. However, it is also possible
to position the loop deeper, as several cores, if deployed, form a coil, as a result
of which the sensitivity of the detection loop is increased and a reliable signal
is obtained despite the larger distance to a vehicle to be detected.
[0049] The multiple-core cable also has the advantage that if during asphalting possibly
one or more cores of the cable have been damaged, another core can be used so that
the desired number of active windings is nonetheless achieved.
[0050] Due to the optional larger sensitivity of the detection loop according to the invention
it is also possible, during laying a new road surface, to place the detection loop
deeper underneath the top layer spaced apart therefrom such as on the foundation layer
or in case of a road surface having three asphalt (concrete) layers disposing it underneath
the intermediate layer and on the sub layer. (Generally an asphalt road surface consists
of three layers, namely a sub layer of approximately a 6 to 7 cm thickness, an intermediate
layer of a 4 to 5 cm thickness and a top layer of a 3 to 4 cm thickness). In this
way the advantage is achieved that in case of repairs to the road surface, or in case
of replacing the top layer the detection loop can remain where it is and is not damaged.
In case of replacing the top layer namely a few centimetres of the intermediate layer
is milled away as well. During repairing the road surface it is of course also possible
to dispose the detection loop according to the invention on the basis layer that has
been milled free.
[0051] In figure 5 an arrangement is shown of four devices 110a-d that as regard build-up
are comparable to the device 10, therefore having a cable 106a-d (corresponding with
cable 6) which by means of tie-wraps is attached to a carrier 101a-d (corresponding
with carrier 1, however, having different outer dimensions). The carriers 101a-d are
now T-shaped, with a transversely projecting portion 119a-d for the connecting sections
109a-d, on which portion the connecting sections are secured by means of tie-wraps.
Double loops 105a-d are attached to the carriers 101a-d. The connecting sections 109a-d
are rolled up as regards their part that extends outside of the projecting portion
119a-d. In figure 5A this is shown more clearly for device 110a. The devices 110a-d
are placed on an asphalt sub layer or intermediate layer transverse to the direction
of driving X. This arrangement, with double loops that in the direction of driving
are placed one behind the other can be used for speed measurements on motorways of
in this case four lanes.
[0052] The devices 110a-d can be supplied in double rolled up condition, wherein, the main
surface of the carrier 101a-d is rolled up in direction X and the projecting portion
119a-d in a direction transverse thereto. When being placed first device 110a is rolled
out and adhered to the freely exposed asphalt surface. Then device 110b follows, wherein
the projecting portion 119b connects to carrier 101a. After that device 110c follows,
wherein the projecting portion 119c connects to carrier 101b. Finally device 110d
follows, wherein the projecting portion 119d connects to carrier 101c. It can be seen
that the projecting portions 119a-d differ in width with a differing distance between
the connecting sections 109a, 109b, 109c and 109d, so that the connecting sections
109a-d can sit next to each other and the assembly thus obtained remains limited in
height. The connecting sections 109a-d jointly exit, situated together, for connection
to a loop coupling box, for instance placed in the verge of the road.
[0053] It is also possible that the carriers bear several loops, such as for instance the
devices 210a,b shown in figure 6, and with their largest length are situated transverse
to the direction of driving X. The carriers 201a,b are each situated in a lane, and
each bear three loops 205a-c. The largest length of the devices 210 can here be adjusted
to three lanes, for instance 9 m.
[0054] Figure 7 also shows a quadruple arrangement, having solitary devices 310a-b, which
as regards build-up can be compared with the device 10, that means with a cable 306a-b
(corresponding with cable 6) which by means of tie-wraps is attached to a carrier
301a-b (corresponding with carrier 1, yet having different outer dimensions). The
projecting portions 319a-b of the carriers 301a-b are now relatively short. The longitudinal
direction of the carriers 301a-b is parallel to the direction of driving X. The length
in said direction may for instance be 20 m. Said arrangement can for instance be used
in a crossroads with traffic lights, with four lanes, such as a lane for turning right,
one for turning left and two for continuing ahead.
[0055] In figures 5-7, for the sake of clarity, the grid size is many times larger than
it will actually be (for instance 2.5 cm).
[0056] The above description is included to illustrate the operation of preferred embodiments
of the invention and not to limit the scope of the invention. Starting from the above
explanation many variations that fall within the spirit and scope of the present invention
will be evident to an expert.
1. Vehicle detection device to be accommodated in a road surface, comprising a cable
having at least one electric conductor and a carrier, wherein the carrier is grid-shaped
having elongated grid elements that in between them define grid meshes, wherein the
cable is attached in advance in the desired loop shape on the grid elements of the
carrier, wherein the carrier preferably can be rolled up at least in one direction.
2. Device according to claim 1, wherein the conductor has a number of singular wires
each provided with a heat resistant coating, particularly lacquer, and together form
a core or litze wire, wherein preferably the singular wires have been stranded into
the conductor.
3. Device according to claim 2, wherein only the singular wires are provided with a heat
resistant coating, particularly lacquer, wherein preferably the cable comprises several
conductors that directly abut one another, particularly have been stranded.
4. Device according to any one of the preceding claims, wherein the cable comprises a
number of electric conductors, preferably seven, that can be connected in series.
5. Device according to any one of the preceding claims, wherein the cable has a sheath
with high-strength fibres, such as for instance Kevlar® and/or wherein the cable is
provided with a layer of water-blocking material arranged around the conductor or
group of conductors.
6. Device according to any one of the preceding claims, wherein the cable is attached
to the grid elements by means of cable binders, wherein preferably the cable binders
are tie-wraps, preferably having a metal locking strip in the locking end, wherein
preferably the locking ends are situated vertically adjacent to the cable and the
tie-wraps have been cut off outside of the locking ends.
7. Device according to any one of the preceding claims, wherein the grid elements are
made of glass fibre and have been impregnated/coated with an asphaltic resin.
8. Device according to any one of the preceding claims, wherein the grid elements form
an open fabric, wherein preferably the grid elements comprise a group of first grid
elements and a group of second grid elements that are perpendicular to the first grid
elements, wherein in one embodiment, at the location of the intersections the second
grid elements engage the first grid elements in an adhering manner at the upper side
and lower side thereof for securing the intersection in the direction of the second
grid elements, wherein preferably the first grid elements are flat-strip-shaped, wherein
preferably the loop is substantially rectangular with long sides and short sides,
wherein the second grid elements extend in the direction of the long sides.
9. Device according to any one of the preceding claims, wherein the device is rolled
up, preferably with the loop on the concave side of the carrier, wherein in case of
dependency on claim 8, the first grid elements preferably extend parallel to the axis
of the roll.
10. Device according to any one of the preceding claims, wherein on the side facing away
from the loop, the lower side, the first and second grid elements are provided with
an adhesive that adheres to an asphalt surface, and preferably is pressure-activated.
11. Device according to any one of the preceding claims, wherein the grid-shaped carrier
can be bent out of its plane, particularly can be rolled up in a second direction
perpendicular to the first direction.
12. Device according to any one of the preceding claims, wherein the mesh width exceeds
1x1 cm, preferably a few cm by a few cm.
13. Device according to any one of the preceding claims, wherein the cable comprises connecting
sections for connection of the loop to a loop coupling box, wherein the carrier has
a main portion for carrying the loop and a part projecting therefrom, forming one
unity with the main portion and to which a part of the connecting sections that connects
to the loop is attached, wherein preferably the part of the connecting sections attached
to the carrier has a length of one or more dm, and/or wherein preferably the loop
is elongated and the projecting part of the carrier projects in a direction transverse
to the longitudinal direction of the loop, wherein preferably the connecting sections
extend with a portion to beyond the carrier and at that location preferably are rolled
up.
14. Device according to any one of the preceding claims, wherein the cable comprises connecting
sections for connection of the loop to a loop coupling box, wherein the loop with
a part of the connecting sections that connects thereto is attached to the carrier,
wherein preferably the connecting sections extend with a portion to beyond the carrier
and at that location preferably are rolled up.
15. Device according to any one of the preceding claims, wherein several cables are attached
to the carrier in loops that are situated next to each other.
16. Method for disposing a detection loop device for vehicles according to any one of
the claims 1-15 in a road surface, wherein the device in rolled up condition, with
particularly the cable on the concave side of the rolled up carrier, is supplied to
the work, rolled out on a basis surface, adhered thereto, preferably by means of a
pressure-sensitive adhesive that has been applied to the carrier, and subsequently
an asphalt layer, which preferably is the covering layer of the paving in question,
is applied, wherein preferably the device is adhered to the top surface of an asphalt-containing
intermediate layer or sub layer, wherein preferably the roll is rolled out in direction
of driving of the traffic that will be using the road surface.
17. Road surface provided with a vehicle detection device according to any one of the
claims 1-15.
18. Traffic system, such as a system including traffic lights, comprising a road surface
according to claim 17.