WO2005103386A1

WO2005103386A1 - System for traffic regulation

Info

Publication number: WO2005103386A1
Application number: PCT/NL2005/000308
Authority: WO
Inventors: Hubertus Johannes Bernardus Schoeren
Original assignee: Schoeren Hubertus Johannes Ber
Priority date: 2004-04-26
Filing date: 2005-04-25
Publication date: 2005-11-03
Also published as: NL1026036C1

Abstract

System for traffic regulation (600) having a speed bump element (200) which can move at least in the vertical or height direction and is provided with a top surface (201) and with a blocking device (100) for selectively blocking and unblocking the speed bump element (200) in the height direction in at least one vertical position thereof, the blocking device (100) comprising at least one vehicle sensor (110), which is located at a certain distance from the speed bump element (200), for detecting the presence of a vehicle, which blocking device (100) can block the speed bump element (200) by means of a force-transmitting medium, such as a liquid, a gas or an (electro-)magnetic force field.

Description

SYSTEM FOR TRAFFIC REGULATION

The invention relates to a system for traffic regulation, alternatively denoted traffic control assembly, in particular a dynamic speed bump, in accordance with the preamble of claim 1. An example of a speed bump of this type is known from the American patent publication bearing number US-A 5,486,065 and is intended to be incorporated as part of a road along which vehicles can drive, with the aim of reducing or at least influencing the maximum (horizontal) speed at which the vehicles drive along the road. One important property of the dynamic speed bump is that it forms little if any obstacle to a vehicle traveling at a speed lower than a limit value, for example a prescribed maximum speed. At least in this specific design, this is achieved by the fact that a top surface of a speed bump element of the known speed bump, which in a first vertical position .is not located in the plane of the road or roadway, but rather in this case projects above it, can be pressed downwards by the weight of a vehicle, via a wheel of the vehicle, relatively easily, i.e. without exerting much resistance, into a second vertical position, in which it lies at least substantially in the plane of the road. This advantageous property prevents the vehicle from being or having to be braked to below the prescribed maximum speed when approaching the speed bump before being accelerated again after it has passed the speed bump. However, if the vehicle speed is above the prescribed maximum speed while the vehicle is passing over the top surface of the speed bump element, the blocking device acting on the speed bump is active, so that the speed bump element cannot or can scarcely be pressed downwards, and therefore continues to project above the roadway, with the result that the vehicle will be subject to more or less abrupt vertical acceleration, which is generally considered unpleasant by the occupants of the vehicle and at relatively high vehicle speeds can even lead to damage to the vehicle. The above entioned advantageous property of the dynamic speed bump is obviously not present in the fixed or static speed bumps which are in widespread use and are generally formed as a local elevation in the roadway, and is also not present in the damped sprung speed bumps which are also known and a number of examples of which are described in the German patent application bearing number DE-A 101 28 410 and the American patent bearing number US-A 6,024,510. Both the latter types of speed bump have the drawback that the traffic is always subject to at least some vertical acceleration, albeit related to the speed of the vehicle, even at a (horizontal) vehicle speed, which is lower than the prescribed maximum speed. In this regard, therefore, the speed bump that is known from US-A 5,486,065 will in principle be preferred. However, when the known design is studied in greater depth, in particular the mechanical construction of the blocking device that is known from the above document appears to entail a significant drawback. This is because there is a possibility of the instance at which a vehicle comes into contact with the speed bump element coinciding with the instant at which the blocking device releases it, i.e. at which it is unblocked. In this event, at least the blocking device is subject to unfavorable, i.e. highly local, load from (inter alia) the weight of the vehicle, which can damage the device or even cause it to fail, thereby endangering correct operation thereof. A solution to this fundamental drawback, which is obvious and described, for example, in patent publication GB-A-2266552 is for a velocity sensor to determine the speed of a vehicle before it approaches the speed bump, at a distance from the speed bump, for example by means of detection loops or by radar or laser detection. If the vehicle speed exceeds the prescribed maximum speed, the speed bump element can then be blocked or unblocked, depending on the principle on which it is based, before the vehicle comes into contact with the speed bump element. However, a design of this type has the drawback of being relatively expensive, on account of the presence of the velocity sensor, which, moreover, has to be positioned at a distance from the speed bump element in order to enable it to be blocked or unblocked in advance. Consequently, this type of speed bump cannot usually be prefabricated as a single unit, and consequently laying it in the road will also entail relatively high costs. Moreover, this design also has the fundamental drawbacks compared to the dynamic speed bump which is known from US-A 5,486,065 that correct operation thereof could be sabotaged relatively easily (for example by fixing the speed bump element using external means) and that the speed bump element has to be either provided with or connected to an electrical power supply. It is an object of the present invention to provide a new type of traffic control assembly which represents an alternative to the known types discussed above and which preferably does not have at least some of the associated drawbacks, or at least only has these drawbacks to a reduced extent. The traffic control assembly according to the invention comprises at least the combination of measures in accordance with claim 1 below. According to the invention, the claimed combination of measures provides a very robust design for the assembly. On account of the fact that the blocking device does not act on the speed bump element directly, i.e. via mechanical coupling, but rather indirectly via a force- transmitting medium, such as a liquid, a gas or an (electro-) magnetic force field, the mechanical load on the blocking device is improved in particular during the above-described releasing or unblocking and blocking of the speed bump element, specifically to a level which allows the assembly to operate autonomously and reliably for a prolonged period of time. Additional advantages of the assembly according to the invention, which, incidentally, will be explained in more detail below with reference to the figures and on the basis of a number of exemplary embodiments, are that the assembly: is particularly suitable for prefabrication as an independent unit, which unit can then easily be incorporated in the road at relatively low cost; can be completely hydro-mechanical in form, in which case there is no need to provide for connection to an electricity grid; and can be provided with a symmetrical structure, so that it can control traffic from two opposite directions and also cannot be sabotaged at least by simple means, a design which will generally also lower the cost price. In a first preferred embodiment of the traffic control assembly according to the invention, the blocking device comprises an electromagnet which, when it is (electrically) energized applies a magnetic field to the speed bump element, with the result that the latter is held in a fixed vertical position, i.e. a fixed position in the vertical direction, with respect to the roadway, i.e. is blocked. In a design of this type, it will be impossible for the releasing or unblocking and/or the blocking of the speed bump element coinciding with the time at which a vehicle comes into contact with it to be able to lead to excessive mechanical loading of the blocking device or the speed bump element: after all, there is no mechanical connection between them, on account of the electromagnetic energizing. In a second preferred embodiment of the traffic control assembly according to the invention, the blocking device comprises a piston-and-cylinder assembly that defines a pressure chamber filled with a fluid, preferably oil, and whereof the piston or cylinder is coupled to the speed bump element. The blocking device is provided with a valve, by means of which the pressure chamber can be at least virtually shut off from the environment, in which case the speed bump element is held in a fixed vertical position, i.e. a fixed position in the vertical direction, with respect to the roadway, i.e. is blocked. In a design of this type, the possibility of the releasing or blocking of the speed bump element by the pressure chamber being opened or closed with respect to the environment with the aid of the valve coinciding with the instant at which a vehicle comes into contact with the speed bump element will not lead to problems of excessive mechanical loading of the blocking device. After all, only a small part of the weight of the vehicle will be supported by the valve via the hydraulic or pneumatic pressure in the pressure chamber. The invention will now be explained in more detail, by way of example, on the basis of the following description of a number of exemplary embodiments of the invention with reference to the drawing, in which identical reference numerals denote identical or similar components and in which: - Figure 1 shows a diagrammatic cross section through a known active traffic control assembly, which also illustrates a fundamental drawback thereof, Figure 2 diagrammatically depicts a first preferred embodiment of an active traffic control assembly according to the invention, Figure 3 shows a diagrammatic cross section through a second preferred embodiment of an active traffic control assembly according to the invention, Figure 4 shows a diagrammatic cross section through a third preferred embodiment of a symmetrically constructed active traffic control assembly which builds on the operating principle of the assembly shown in Figure 3, Figure 5 shows a plan view of a third preferred embodiment according to the invention from Figure 4, which in this example is installed in a transport and positioning unit, - Figure 6 shows a diagrammatic cross section through a fourth preferred embodiment of an active traffic control assembly according to the invention, Figure 7 shows another diagrammatic cross section through the fourth preferred embodiment according to the invention, and in which Figure 8 shows a diagrammatic cross section through a fifth preferred embodiment of an active traffic control assembly according to the invention. Figure 1 shows an example of a known traffic control assembly 600, which is accommodated in the road with road surface 601. Although provided with a symmetrical structure, the known construction will be described for the situation in which a vehicle is driving over it from the right to left. In a situation of this type, a front wheel of a vehicle first of all comes into contact with the vehicle sensor 615a, which projects above the road surface 601, of a mechanically operating blocking device of the assembly 600, which in this example comprises the components 615a, 602, 604a, 614, 612, 617, 616, 620, 630 and 642. The vehicle sensor 615a is pressed downwards by the weight of the vehicle, which is associated with a rotation of a first arm 602 about a respective rotation spindle 604a of the arm 602. This rotation is transmitted via the contact blocks 614 to a second arm 603, which as a result will rotate in the opposite direction about a rotation spindle 604b. An end 612 of the second arm 603 sets an obstruction block 616 in motion, which for this purpose is provided with a contact lip 617. In the process, the obstruction block 616 rotates about a pin 620 positioned eccentrically with respect to the mass centre of the obstruction block 616, in such a manner that a part 630 of the obstruction block 616 is pushed between an anvil 642 and the second arm 603 until the position indicated by the dashed-line contour 626 is reached. On account of the eccentric positioning of the spindle 620, the obstruction block 616 will then rotate back, under the force of gravity, into its original position, indicated by the continuous contour. If the front wheel of a vehicle then comes into contact with a speed bump element 615b of the assembly 600, the latter can be pressed downwards without being impeded, or at least rotated via the second arm 603, about the rotation spindle 604b, as far as the anvil 642, so that the vehicle is subject to little if any vertical acceleration. However, if the speed of the vehicle is higher than a maximum speed prescribed by the assembly 600, the front wheel of the vehicle comes into contact with the speed bump element 615b before the obstruction block 616 has rotated back, while it is in the position, for example, indicated by the dashed-line contour 626. This prevents the speed bump element 615b from being pressed down as described above, and consequently the vehicle is subject to the abrupt vertical acceleration, which is intended under these conditions. Although this property of the known traffic control assembly 600 is highly advantageous, since in particular vehicles which respect the prescribed maximum speed are spared, its mechanical design has a fundamental drawback which endangers long-term and/or reliable operation thereof, or at least makes it impossible to make the assembly 600 more compact and lightweight. This is because if the instant at which the vehicle comes into contact with the speed bump element 615b coincides with the instant at which the obstruction block 616 is just in the process of rotating (back) , the situation may arise whereby the obstruction block is subjected to a very local load, for example at the location of the corner 631 of said part 630 thereof, and therefore to a high contact pressure. Moreover, depending in particular on the strength of the structure and in particular the obstruction block 616, the pin 620 will start to bear at least part of the weight of the vehicle. To avoid this drawback of the known design but at the same time to allow its advantageous properties to be retained, the present invention proposes an alternative design of the traffic control assembly 600, in particular its blocking device 100. Figure 2 shows a first preferred embodiment of an active traffic control assembly 600 according to the invention. The speed bump element 200, which is preferably substantially in the form of a bar and has a top surface 201 in the assembly 600, at least in a load-free situation, is held by means of a spring 210 in the first vertical position shown, in which it projects above the road surface 601. An anvil 220 is provided for limiting the freedom of movement of the speed bump element 200 in the downward direction, preferably in such a manner that the top surface 201 thereof can be pressed down as far as the road surface 601, i.e. into its second vertical position. The blocking device 600 of the assembly 600 is substantially electronic in form and comprises a vehicle sensor 110, such as the known electro- magnetically operating detection loop accommodated in or below the road surface 601, for locally detecting the presence of a vehicle, or at least a wheel 1 thereof, at a certain distance from the speed bump element 200. Furthermore, the blocking device 100 is provided with a number of electromagnets 120 acting on a flange 202 of the speed bump element 200 and with a control unit 130 for selectively energizing the electromagnets 120. If the vehicle sensor 110 detects the presence of a vehicle, it emits a vehicle detection signal to the control unit 130, which in response to this signal energizes the electromagnets 120 for a defined period of time. As a result, the flange 202 of the speed bump element 200 is pulled towards the electromagnets 120, with the result that the latter is fixed, i.e. blocked, in the first vertical position shown, in which it projects above the road surface 601. After said period of time has elapsed, the electromagnets 120 are no longer energized, and the speed bump element 200 can be pushed downwards again, with the spring 210 being compressed. If the wheel 1 of the vehicle comes into contact with the speed bump element 200 within said period of time, the speed bump element 200 cannot be pressed down, with the result that the vehicle is subject to the sudden vertical acceleration, which is intended under these conditions, over the speed bump element 200 which projects above the road surface 601. Normally, the period of time will be at least approximately given by the quotient between a distance from the vehicle sensor 110 to the speed bump element 200 and a maximum speed prescribed for the vehicle at that location. Figure 3 shows a second preferred embodiment of an active traffic control assembly 600 according to the invention. In this embodiment, the blocking device 300 comprises at least one piston-and-cylinder assembly 311-313, whereof the piston 311 is coupled to the speed bump element 200, supporting the latter in the vertical or height direction. The piston-and-cylinder assembly 311-313 defines a pressure chamber 313 filled with a fluid, preferably oil, and is provided with a valve 314, by means of which the pressure chamber 313 can be closed off from the environment, for example a reservoir 315 for the fluid. If the valve 314 is closed, the volume of the pressure chamber 313, depending on the compressibility of the fluid, will be unable or scarcely able to change, in which case the speed bump element 200 is held in a fixed vertical position or height above the road surface 601, i.e. is blocked. The blocking device 300 of the assembly 600 also comprises, at a certain distance from the speed bump element 200, a vehicle sensor 320 for detecting the presence of a vehicle, or at least a wheel 1 thereof, at that location and a control unit 330 for selectively closing and opening the valve 314. Now, in the load-free situation, the speed bump element 200 is also held in the position shown, in which it projects above the road surface 601, by the spring 210. In this case too there is an anvil 220 for limiting the freedom of movement of the speed bump element 200 in the vertically downward direction. If the vehicle sensor 320 detects the presence of a vehicle, it emits a signal to the control unit 330, which in response to this signal closes the valve 314 for said period of time. As a result, the speed bump element 200 is fixed in the first vertical position shown, in which it projects above the road surface 601, i.e. is blocked. After said period of time has elapsed, the valve 314 is opened by the control unit 330, and the speed bump element 200 can again be pressed downwards into its said second vertical position, by virtue of the fact that the fluid can then flow out of the pressure chamber 313 via the valve 314 to the reservoir 315. If the wheel 1 of the vehicle comes into contact with speed bump element 200 within said period of time, the speed bump element 200 cannot be pressed downward, so that the vehicle undergoes the abrupt vertical acceleration over the speed bump element 200 which is desired under these conditions.

Although it is readily conceivable and possible for the structure comprising the vehicle sensor 320 and the control unit 330 to be designed completely or partially as an electronic system, for example in accordance with the detection loop 110 and electronic control unit 130 described above, which then interacts with an electro- magnetically actuable valve 314, in the embodiment of the invention shown, the vehicle sensor 320, the control unit 330 and the valve 314 are substantially mechanical in terms of structure and operation. In this example, the vehicle sensor 320 comprises a bar-shaped ridge 320, which is held in a position projecting slightly above the road surface 601 with the aid of a spring 321. It is pressed downward under the influence of the weight of a vehicle passing over the ridge 320, with the result that the control unit 330 is activated. In this case, the control unit 330 comprises a linkage mechanism made up of three rods 331, 332 and 333 with two hinge mechanisms 334 and 335 between them, the middle or intermediate rod 332 being incorporated in the mechanism in such a way that it can rotate about an axle 336. If the first rod 331 is pressed downwards by the ridge 320, the intermediate rod 332 rotates about the axle 336 and the third rod 332 is moved upwards, rotating the valve 314 to the right and thereby closing it. The valve 314 is provided by a spring, which makes it rotate back and open again. However, it takes a certain time for this to happen, so that if the various components are selected appropriately, the cylinder 313 will remain closed for the desired period of time. A completely mechanical structure of this type is particularly suitable for prefabrication as an autonomous unit, which can then be laid in the road. Of course, the vehicle sensor 320 and the speed bump element 200 are preferably positioned at a short distance from one another so that, for example in the event of a trailer with two axles positioned centrally beneath the trailer, passing over it, the wheels of a rear axle of a vehicle, as seen in the direction of travel, do not pass over or activate the vehicle sensor 320 before the wheels of the front axle of the vehicle have passed over the speed bump element 200 or at least pushed it downwards to the road surface 601. As an alternative, it is also possible for the blocking device 300 to be designed in such a manner that after said period of time for which the speed bump element 200 is blocked, this speed bump element cannot be blocked for a following second period of time, i.e. during this second period of time the speed bump element can always be pressed downwards irrespective of the speed of the vehicle. The result of this is that the assembly is only active in relation to said front axle, thereby preventing, for example, the blocking device 300 from being activated by the rear axle of the vehicle before said front axle has passed over the speed bump element 200. Figure 4 provides a more detailed view of the second preferred embodiment of the active traffic control assembly 600 according to the invention shown in Figure 3, in the form of a symmetrical structure. The traffic control assembly 600 shown in Figure 4 is provided with two speed bump elements 200a, 200b, which are located at a distance from one another in a direction of travel of the traffic and simultaneously serve as a vehicle sensor 320 of the blocking device 300. In the at-rest state in the first vertical position, both speed bump elements 200a, 200b project above the road surface 601 in the vertical or height direction. The speed bump elements 200a, 200b can be held in this position, for example with the aid of the abovementioned spring 210. Both speed bump elements 200a, 200b are provided with a piston-and-cylinder assembly 311a-313a; 311b-313b, the respective pressure chambers 313a, 313b of which are connected to one another via a reservoir 315. Two valves 314a, 314b are provided and are each positioned between one of the two piston-and-cylinder assemblies 311a-313a and 311b-313b and the reservoir 315 such that they can selectively close or open the hydraulic connection between these components. The valves 314a, 314b are in this case controlled by a control unit 330, which is provided with two electronic detection circuits 317a, 317b, which can each be closed by an associated speed bump element 200a, 200b, which then serves as a vehicle sensor 320, being pressed downwards. As a result of one of the two electronic detection circuits 317a, 317b being closed, the control unit 330 generates the abovementioned vehicle detection signal, which can then, moreover, be assigned to one of the two speed bump elements 200a, 200b. In the design shown in Figure 4, the presence of a vehicle is detected if the wheel 1 thereof comes into contact with a first of the two speed bump elements 200a, 200b, for example the element 200a situated on the left-hand side in the figure, and the latter is pressed (vertically) downward. The associated, i.e. first, speed bump element 200a therefore functions as vehicle sensor 320. At the same time as the first speed bump element 200a is pressed downwards, fluid flows out of the pressure chamber 313a of the associated piston- and-cylinder assembly 311a-313a, via said hydraulic connection and the valve 314a, to the reservoir 315. This speed bump element 200a also closes one of the two detection circuits 317a, so that an associated vehicle detection signal is generated in the control unit 330, in response to which the valve 314a associated with the other, right-hand, speed bump element 200b is closed for said period of time by the control unit 330. If the wheel 1 comes into contact with the second speed bump element 200b within this period of time, this speed bump element 200b cannot or can scarcely be pressed downwards, and the vehicle is subject to the sudden vertical acceleration which is intended under these circumstances. However, if the wheel 1 comes into contact with the second speed bump element 200b at a later time, i.e. after said period of time has elapsed, the connection between the latter pressure chamber 313b is opened again by the respective valve 314b being opened by the control unit 330, and it is relatively easy for the second speed bump element 200 to be pressed downwards by the weight of the vehicle. Of course, it is possible for one or more out of the change in the flow of the fluid through the respective valves 314a, 314b, the profile of the pressure changes in the respective pressure chambers 313a, 313b and possibly other parameters to be used as the vehicle detection signal. It is also possible for the control unit 330 to be of fully mechanical design. According to the invention, in particular the traffic control assembly 600 shown in Figure 4 provides a relatively simple, completely independent structure with a small number of components which, moreover, is active for traffic from two opposite directions and cannot - at least easily - be sabotaged by fixing one or both speed bump elements 200a, 200b using external means . Figure 5 illustrates a transport and positioning unit 700 in which the structure according to the invention corresponding to Figure 4 is accommodated. The top surfaces 201 of the two speed bump elements 200 thereof are visible. A positioning unit 700 also comprises the section of the road surface 601 which is located between the speed bump elements 200 as well, in this example, as reflectors 701 and a lifting eyelet 702, making it easy for the unit to be positioned in the road. Furthermore, a unit of this type is particularly advantageous, since it can be positioned and removed, for example for centralized maintenance or repair, not only at relatively low cost but also very quickly, with the additional important advantage of causing scarcely any disruption to the traffic. Figure 6 illustrates a fourth preferred embodiment of an active traffic control assembly 600 according to the invention. In this embodiment, the blocking device 300 once again comprises a piston-and-cylinder assembly 311-313 with one valve 314 per speed bump element 200a, 200b, and is therefore of corresponding structure to the blocking devices 300 from the second and third preferred embodiments discussed above. Moreover, this fourth preferred embodiment, like the third preferred embodiment according to the invention, is of symmetrical structure, so that in this case too the two speed bump elements 200a, 200b also serve as the vehicle sensors 320 of the blocking device 300. However, the difference with respect to the earlier preferred embodiments is that, at least in the load- free situation, the top surface 201 of the two speed bump elements 200a, 200b is located at least virtually in the plane of the road surface 601. Moreover, in this construction the speed bump elements 200a, 200b are normally, i.e. in the load-free situation, both blocked, in which case, more particularly, the two valves 314 are closed. Therefore, in their first vertical position shown in Figure 6, the speed bump elements 200a, 200b are fixed in the plane of the road. If necessary, the speed bump elements 200a, 200b are unblocked, in which case the respective top surface 201 thereof can be pressed downwards by the wheel 1 of a vehicle into the second vertical position, which now lies below the plane of the road surface 601, in such a manner that it is as if the vehicle has driven through a pothole and in the process has undergone the vertical acceleration which is then desired. In the structure shown in Figure 6, the presence of a vehicle is detected if its wheel 1 comes into contact with a first of the two speed bump elements 200a, 200b, for example the left-hand element 200a in the figure. Although at that time this first speed bump element 200 is blocked in said first vertical position, and therefore will not be pressed downward, the presence of the vehicle can still be detected, for which purpose the present invention proposes the following options by way of illustration. Firstly, the load which the wheel 1 of the vehicle exerts on the speed bump element 200a can be detected, for example with the aid of a pressure sensor in the pressure chamber 312 of the associated piston-and- cylinder assembly 311-313, or by means of a piezoelectric pressure sensor below the cylinder 313 thereof. Secondly, an albeit very slight downward movement of the speed bump element 200a resulting from the compressibility which is still present in the fluid can be detected. It is also possible to arrange a relatively small opening or leak in the piston-and- cylinder assembly 311-313 in parallel with the valve 314, through which a small quantity of fluid, such as a hydraulic medium, can flow under the influence of the increase in pressure resulting from the load exerted by the vehicle, which flow can be detected, or with the result that a slight but detectable downward vertical movement of the speed bump element 200a is obtained. It should be noted that, of course, an additional vehicle sensor 320 could be used, which is independent of the speed bump element 200a, 200b, for example one or more of the detection loop 110 in accordance with the embodiment shown in Figure 2. In a design of this type, it would be possible to make do with a single speed bump element 200. In response to the vehicle or at least the wheel 1 thereof being detected at the location of the first speed bump element 200a, which therefore functions as vehicle sensor 320, an associated vehicle detection signal is generated, and in response to this the second speed bump element 200b is unblocked or released for said time period. In this exemplary embodiment, said unblocking is effected by opening the valve 314 associated with the second speed bump element 200b. If the wheel 1 comes into contact with the second speed bump element 200b within this period of time, said second speed bump element 200b can be pressed downwards, with fluid flowing out of the associated pressure chamber 312 via the associated valve 314 and the vehicle being subjected to the sudden vertical acceleration which is intended under these circumstances. This situation is illustrated in Figure 7 for the traffic control assembly 600 from Figure 6. However, if the wheel 1 comes into contact with the second speed bump element 200b at a later stage, i.e. after said time period has elapsed, the latter valve 314 has closed again and the associated speed bump element 200b is fixed in the vertical or height direction, so that the vehicle can pass over it unimpeded. According to the invention, the speed bump elements 200a, 200b, in the same way as in the previous exemplary embodiments, can be provided with a spring 210, which presses the associated speed bump element 200a, 200b, at least in said load-free situation, into its uppermost position which it is intended to occupy, in which the top surface 201 of the speed bump element 200a, 200b is level with the road surface 601. It is also possible for the speed bump element 200a, 200b, after it has been pressed downwards as described above, to be returned into the uppermost position by fluid being pumped (back) into the pressure chamber 312. A significant advantage of this fourth preferred embodiment of an active traffic control assembly 600 according to the invention, which has been illustrated with reference to Figures 6 and 7, is that traffic which sticks to the maximum speed is (virtually) unimpeded by the presence of the speed bump elements 200a, 200b, since the top surface 201 thereof, in said first vertical position, is located in or virtually level with the plane of the surrounding road 601. In addition, this assembly 600 provides for the possibility of not reacting to or being activated by more vulnerable and generally lightweight elements of traffic than the abovementioned motor vehicles, such as moped riders, cyclists and/or motorcyclists, who in that case can pass over the speed bump elements 200a, 200b without obstacle and in particular without danger or great discomfort. This latter possibility can be achieved on the one hand by only generating the associated vehicle detection system if a threshold value for the abovementioned load exerted on the speed bump element 200a is exceeded. On the other hand, the speed bump elements 200a, 200b can be supported by relatively strong springs 210 (i.e. springs with a sufficiently high spring rate) , so that they are not or are scarcely pressed downward under a relatively low load but are pressed downward under a load exerted by a vehicle. Finally, Figure 8 shows a fifth preferred embodiment of an active traffic control assembly 600 according to the invention, which has a similar structure to that of the fourth preferred embodiment thereof discussed above, and the corresponding components of which are denoted by corresponding reference symbols. In the latter structure, the speed bump elements 200a, 200b are each provided with a rotating support or spindle 202, with the result that they execute a rotary movement when, in the unblocked or released state, they are pressed vertically downward to below the race surface 601 by the wheel 1 of the vehicle. This specific embodiment has the advantage that the wheel 1, on leaving a speed bump element 200b which has been pressed down, does not strike a high and sharp edge 602 of the surrounding road surface 601, as is the case in the embodiment shown in Figure 7. As a result, the shock loading on both the vehicle and said edge 602 will be kept below an acceptable limit, even if the speed bump element 200b can be pressed a relatively large distance downwards in the height direction. The present invention also provides a number of new and unexpected possible uses and applications for the above-described traffic control assembly 600 according to the invention, but more generally also for the known types of dynamic speed bumps. In a first new application of the dynamic speed bump, according to the invention the latter is designed in such a manner that said period of time for blocking or releasing or unblocking the speed bump element 200 is of a different duration for traffic coming from the two opposite directions (of travel) , so that the speed bump element is active for different maximum vehicle speeds, which in extremis can be selected to be virtually equal to zero for traffic coming from one direction. In the latter case, if appropriate just one vehicle sensor 110, 320 can be used. This allows the speed bump to be used to mark oneway roads or carriageways and to warn the drivers of the vehicles if they are using (or attempting to use) a particular lane contrary to local traffic regulations, for example by using a one-way road in the opposite direction to the (intended) direction of travel, for example via an exit slip road, or when traffic is using a lane from a direction which is opposite to the direction of travel intended for this lane, for example where overtaking is prohibited or at a middle lane intended as a rush-hour lane for traffic from one of two directions of travel, this direction of travel changing as a function of the volume of traffic. In a second novel application of the dynamic speed bump, according to the invention the latter is designed in such a manner that the duration of said period of time for blocking or unblocking or releasing the speed bump element 200 can be varied, for example by using appropriate electronic control units 130, 330. As a result, the speed bump can be used to be adapted to a variable maximum speed, for example a temporary reduction in maximum speed when there is a risk of traffic jams forming, or to alternately open and/or close a lane, for example in order to open a hard shoulder of a motorway at rush hour as a rush-hour lane or to discourage the use of what are known as rat runs at rush hour. In a third novel application of the dynamic speed bump, according to the invention the latter is designed in such a manner that it can detect the approach of an emergency vehicle, such as a fire engine, and in such a situation will move the speed bump element 200 into a position in which the corresponding vehicle can pass over the speed bump unimpeded and at high speed.

Claims

1. Traffic control assembly (600) having a speed bump element (200) which can move in the vertical or height direction between at least two positions and is provided with a top surface (201) and with a blocking device (100, 300) for selectively blocking and unblocking the speed bump element (200) in the height direction in at least one vertical position thereof, the blocking device (100, 300) comprising at least one vehicle sensor (110, 320, 200), which is located at a certain distance from the speed bump element (200) , at least for detecting the presence of a vehicle, characterized in that the blocking device (100, 300) can block the speed bump element (200) by means of a force-transmitting medium, such as a liquid, a gas or an (electro-) magnetic force field.

2. The traffic control assembly (600) as claimed in claim 1, characterized in that the blocking device (100, 300) is designed to block or unblock the speed bump element (200) by means of the blocking device (100, 300) for a defined time interval in response to the detection of a vehicle by the vehicle sensor (110, 320, 200).

3. The traffic control assembly (600) as claimed in claim 1 or 2, characterized in that the blocking device (100) comprises at least one electromagnet (120) for blocking the speed bump element (200) by applying a magnetic field to it.

4. The traffic control assembly (600) as claimed in claim 3, characterized in that the speed bump element is provided with a flange (202) on which the magnetic field of the electromagnet (120) acts while the electromagnet is electrically energized.

5. The traffic control assembly (600) as claimed in claim 3 or 4, characterized in that the blocking device

(100) comprises a control unit (130) for selectively energizing the electromagnet (120) .

6. The traffic control assembly (600) as claimed in claim 5, characterized in that the top surface (201) of the speed bump element (200), at least in a load-free situation, projects vertically above a roadway (601) surrounding the speed bump element (200), and in that the control unit (130), under the control of a vehicle detection signal from the vehicle sensor (110) , energizes the electromagnets (120) for a defined period of time and then deactivates them again.

7. The traffic control assembly (600) as claimed in claim 5, characterized in that the top surface (201) of the speed bump element (200), at least in a load-free situation, is located vertically at least approximately in the plane of a roadway (601) surrounding the speed bump element (200) , and in that the control unit (130) , under the control of a vehicle detection signal from the vehicle sensor (110) , deactivates the electromagnets (120) for a certain period of time and then energizes them again.

8. The traffic control assembly (600) as claimed in claim 1 or 2, characterized in that the blocking device (300) comprises at least one piston-and-cylinder assembly (311-313), of which the piston (311) or cylinder (312) is coupled to the speed bump element (200) , and of which a pressure chamber (313) is at least partially filled with a gaseous or liquid fluid for blocking the speed bump element (200) by closing off the pressure chamber (313) from the environment.

9. The traffic control assembly (600) as claimed in claim 8, characterized in that the blocking device (300) is provided with a valve (314), by means of which the cylinder (313) can optionally be closed off from the environment, and with a control unit (330) for selectively opening and closing the valve (314) .

10. The traffic control assembly (600) as claimed in claim 9, characterized in that the top surface (201) of the speed bump element (200), at least in a load-free situation, projects vertically above a roadway (601) surrounding the speed bump element (200) , and in that the control unit (330) , under the control of a vehicle detection signal from the vehicle sensor (320), closes off the pressure chamber (313) from the environment for a defined period of time and then opens it up again to the environment.

11. The traffic control assembly (600) as claimed in claim 9, characterized in that the top surface (201) of the speed bump element (200) , at least in a load-free situation, is located vertically at least approximately in the plane of a roadway (601) surrounding the speed bump element (200) , and in that the control unit (330) , under the control of a vehicle detection signal from the vehicle sensor (320) and with the aid of the valve (314), opens the pressure chamber (313) to the environment for a defined period of time and then closes it off again from the environment.

12. The traffic control assembly (600) as claimed in one or more of the preceding claims, characterized in that it is also provided with a spring (210) which acts on the speed bump element (200) in the vertical direction.

13. The traffic control assembly (600) as claimed in one or more of the preceding claims, characterized in that it is also provided with an anvil (220) , which limits movement of the speed bump element (200) in the downward direction.

14. The traffic control assembly (600) as claimed in one or more of the preceding claims, characterized in that the speed bump element (200) and the vehicle sensor (320) are shaped and operate in a corresponding way.

15. Method for controlling traffic, in particular the speed of a vehicle, in which, if a vehicle sensor (110,

320), located at a certain distance from a speed bump element (200) which can move at least in the vertical or height direction, of a blocking device (100, 300) detects the presence of a vehicle, the blocking device (100, 300) blocks or unblocks the speed bump element (200) in the vertical direction for a defined period of time, characterized in that the blocking device (100, 300) acts on the speed bump element (200) with the aid of a force-transmitting medium, such as a liquid, a gas or an (electro-) magnetic force field.

16. Method according to claim 15, in which said time period is determined by the quotient of the abovementioned distance between the vehicle sensor (110, 320) and the speed bump element (200) and a maximum speed prescribed for the vehicle.

17. The method as claimed in claim 15 or 16, in which the speed bump element (200) , at least in a load-free state, is in the same vertical position both in the situation in which it is blocked and in the situation in which it is unblocked.