FR2875933A1 - VEHICLE TRAFFIC SPEED LIMITATION SYSTEM AND SPEED LIMITATION METHOD - Google Patents

Abstract

The invention relates to a system for limiting the speed of circulation (1) of motor vehicles (2) on a traffic lane (3) comprising at least one transmitting beacon (4) of signals (4a, 4b, 5a, 5b) provided for equipping the traffic lane (3), these signals indicating a value representative of the speed limit (6) not to be exceeded on a section of the taxiway (7) .The beacon (4) comprises first and second antennas directional transmitters (8a, 8b), respectively outputting first and second directional signals (4a, 5a, 4b, 5b) in respective first and second directions of traffic on the taxiway, thereby defining first and second circulation geographical areas (9a, 9b) different from each other.

Description

SYSTEM FOR LIMITING TRAFFIC SPEED OF

  VEHICLE AND METHOD FOR LIMITING SPEED

  The present invention generally relates to a system and method for limiting the speed of at least one vehicle.

  More particularly, the invention relates to a system for limiting the speed of traffic of motor vehicles on a traffic lane comprising at least one signal-emitting beacon intended to equip the traffic lane, these signals indicating a value representative of the speed limit to do not go over a section of the taxiway.

  In order to allow the indication of the authorized speed limit in a given traffic zone of a section of taxiway, systems have been developed.

  Certain systems make it possible to emit signals intended for vehicles traveling on a lane and indicating to these vehicles the speed limit not to be exceeded.

  A speed limitation system of the previously defined type, allowing the emission of signals indicating a value of the limit speed not to be exceeded, is described, for example, in patent document FR 2 792 445.

  This document discloses the use of a beacon with a directional antenna directed towards the taxiway to transmit signals indicating the limit value of the speed that the vehicle must meet after passing a signaling beacon. This beacon is placed on a roadside and provides an indication of the maximum speed not to be exceeded for vehicles traveling on one side of the taxiway.

  In this context, the present invention aims to provide a system for informing vehicles of the value of the speed limit to be respected on a lane, this system must be reliable and usable to inform vehicles running on the same way and in different senses.

  To this end, the speed limitation system of the invention, furthermore in conformity with the generic definition given in the preamble defined above, is essentially characterized in that the beacon comprises first and second directional transmitting antennas, respectively transmitting first and second directional signals in first and second respective traffic directions on the taxiway, thereby defining first and second different traffic areas of each other.

  The fact that a transmitting antenna transmits a signal in a given direction makes it possible to define a geographical area with which a value representative of the limit speed not to be exceeded is associated.

  The orientation of the two antennas in different directions makes it possible to define two geographical zones each having a specific value representative of the speed limit not to be exceeded. With this system, when a vehicle equipped with a receiving device receives a signal transmitted by the beacon, this means that the vehicle is in a geographical circulation area whose speed limit is indicated by the signal. Whenever the vehicle changes its geographical zone, it receives by the signal which is preferably transmitted continuously, a value representative of the speed to be respected in this new zone. In this way each vehicle equipped with a particular receiver device and traveling on a traffic lane itself equipped with the system of the invention is informed of the current value of the speed to be respected in the area where it is located, at each once they pass close to a beacon of the system of the invention, and this, regardless of the direction of traffic of the vehicle on the track.

  The fact that the same beacon comprises several antennas is advantageous because it makes it possible to define a speed limitation zone by arranging a beacon at the boundary of this zone. A vehicle entering the zone receives the signal informing it of the speed to be respected in the zone where it is located. It is therefore not necessary to have a transmitter beacon in the direction of traffic on the track, nor a beacon for transmitting a long-range signal. As a result, the system of the invention, while generating short-range signals (since these signals must be practically only present at the border between two geographical areas) remains reliable.

  For example, the signals emitted by a beacon may have a range of at least 10 meters. It can also be arranged that the beacon includes first and second transmitters respectively connected to the first and second antennas of the beacon. The fact that the beacon includes an antenna transmitter reduces the probability that a beacon will emit no signal, and also reduces the risk of interference between the signals emitted by this beacon.

  It can also be ensured that the first directional signals indicate a first representative value of limit speed not to be exceeded and the second directional signals indicate a second representative value of limit speed not to be exceeded, the first representative value being different from the second representative value.

  It can also be ensured that the system comprises at least one receiving device adapted to be embedded in a vehicle, said receiver device being adapted to receive the directional signals from said at least one transmitting beacon, and to interpret said signals. received to at least determine a value representative of the current limit speed not to be exceeded, the device further comprising a memory adapted to store at least said value representative of the current limit speed not to exceed.

  The representative value of the current limit speed is the last value representative of the speed limit received by the receiving device. This value representative of the current limit speed is replaced by a new value representative of the current limit speed at least each time the receiving device interprets a new current value, different from the previous one.

  The value of the current limit speed not to be exceeded may be equal to the value representative of this speed, or be a function of the representative value, this function being defined in the system.

  In the same context, the present invention also relates to a method for limiting the speed of a motor vehicle, characterized in that it consists in successively: transmitting, in a first given geographical zone and to the vehicle, signals indicating a value representative of the limit speed not to be exceeded and a representative value of maximum distance to be traveled at this speed limit not to be exceeded; receiving, with the aid of a receiver device on board the vehicle, said signals and interpreting these signals to determine a current limit value of speed not to be exceeded and the value of the maximum distance to be traveled; record the current limit value of speed not to be exceeded and the value of the maximum distance to be traveled; - evaluate the distance traveled by the vehicle since the registration of said values; - and, as long as the distance traveled by the vehicle since the recording of said values is less than the maximum distance to be traveled, inform the driver of the vehicle the current value of speed not to exceed and / or limit the actual speed of the vehicle by function of the current limit speed value not to be exceeded.

  With this method according to the invention, it is possible to determine geographical areas in which the speed is limited and to signal to the driver the current value of the speed not to exceed and / or limit the speed of the vehicle according to this current value, without the need to have transmitter beacons throughout the geographical area. Indeed, thanks to the method according to the invention it is only necessary to have beacons near the traffic lanes, at the boundary between two different geographical areas with different speed limits.

  Other features and advantages of the invention will emerge clearly from the description which is given below, for information only and in no way limitative, with reference to the accompanying drawings, in which: FIG. 1 represents a layout plan of beacons the system according to the invention so as to define two geographical areas each having a given speed limitation; FIG. 2 represents a schematic view of a beacon according to the invention; FIG. 3 represents a view of a vehicle circulating near a beacon of the system according to the invention; FIG. 4 represents a view from above of a portion of taxiway, the ends of which are equipped with beacons according to the invention, thus defining geographical zones for limiting the speed of circulation.

  As previously announced, the invention relates to a system for limiting the speed of circulation 1 of motor vehicles 2 on a traffic lane 3 comprising at least one transmitting beacon 4 of signals. As shown in FIG. 1, the beacons are arranged along the lanes connecting a first geographical zone 9a having a particular speed limitation value to another geographical zone 9b, having another particular speed limitation value. The signals emitted by the beacon are radio frequency signals transmitted continuously.

  In order to prevent a vehicle from changing geographical area without being warned and without receiving a current speed limit signal at the time of the zone change, beacons are placed near the border between the zones along the border. each lane 3 leaving or entering the zone 9a.

  Therefore, even if the area to be defined is very wide (a whole agglomeration), it can be simply delimited with as many beacons as traffic lanes connecting this area to another.

  FIG. 2 is a schematic view of a beacon according to the invention provided with first and second independent emitters 10a and 10b, each emitter being connected to a corresponding directional antenna 8a, 8b. Each antenna of the same beacon 4 is oriented in a direction substantially opposite to the direction of transmission of the other directional antenna of the same beacon 4, so that the signals emitted by each antenna are not superimposed on the same area geographical.

  FIG. 3 represents a beacon 4 implanted on the edge of a taxiway and emitting on either side of the beacon, and in opposite directions substantially parallel to the axis of the taxiway, signals indicating a value representative of the speed limit 6 not to be exceeded on each section of the taxiway 7 and on both sides of the beacon 4.

  The first and second directional transmitting antennas 8a, 8b, respectively emit first and second directional signals 4a, 4b in respective first and second directions of circulation on the taxiway.

  In the case of Figure 3, the vehicle is moving towards the beacon and first receives the second directional signal 4b from the second directional antenna. The directional antennas are oriented such that the same vehicle receives at a given moment only one of the first or second directional signals thus defining the geographical circulation zone 9a or 9b in which the vehicle is located. Thus, once the vehicle of Figure 3 away from the beacon, it receives a second signal 4b indicating that the vehicle has changed geographical area and also indicating the new value of the speed limit that the vehicle must not exceed.

  A receiver device 11 is embedded in the vehicle and provided with information means adapted to signify, to a user of the system, the current limit speed value not to be exceeded. Such information means may include sound signaling by loudspeaker and / or visual signaling by display on a screen or by means of indicator lights integrated into the passenger compartment of the vehicle.

  The receiving device 11 which has an omnidirectional receiving antenna and which is embedded in the vehicle 2, is adapted to receive the directional signals 4a, 4b, 5a, 5b from the transmitting beacons 4, 5 of the system.

  Upon receiving a signal from a beacon of the system, the receiving device 11 interprets said received signal to determine a value representative of the current limit speed not to be exceeded. The device further comprises a memory adapted to store at least said value representative of the current limit speed not to be exceeded.

  The receiver device 11 comprises a speed limiting means 12 adapted to automatically limit the real speed of a vehicle 2 on which the receiving device is embarked, this actual speed being limited by the speed limiting means as a function of said limit value. current stored. Thus, for example if the current limit speed is 50 km / h, the limiting means can actuate the engine control system to ensure that the vehicle does not exceed the current limit speed.

  FIG. 4 shows a main traffic lane on which a vehicle 2 is traveling. First and second beacons 4 and 5 are installed on the edge of the lane and on either side of the zone in which the speed is limited so that that a vehicle equipped with the receiving device and passing on the way, receives, at first, the first signals of the beacon, when it goes towards the beacon, then, in a second time receives second signals of the beacon when he moves away from this beacon, continuing his journey always in the same direction.

  Thus, when passing close to the beacon, the receiver perceives a signal change which successively passes from the first signals to the second signals and which indicates that the speed limit has changed. Beacons 4 and 5 transmit signals to the interior of zone 7 indicating one and the same limit speed value. Thanks to this system the limit between two zones is defined with an accuracy of a few meters.

  Preferably, each signal transmitted by the beacon also includes a value representative of the maximum distance to be traveled at this speed limit not to be exceeded, and the onboard receiver device on board the vehicle is connected to an odometer or a means of evaluating the the distance traveled by the vehicle.

  When the vehicle has traveled a distance greater than the maximum distance not to be exceeded, the receiving device then considers that the vehicle has left the area which was covered by the speed limit. This feature makes it possible to take into account the possibility that a beacon is defective and does not transmit the signal correctly to the receiver passing in front of the beacon.

Claims (8)

  1. A system for limiting the speed of movement (1) of motor vehicles (2) on a taxiway (3) comprising at least one transmitting beacon (4) of signals (4a, 4b, 5a, 5b) intended to equip the traffic lane (3), these signals indicating a value representative of the speed limit (6) not to be exceeded on a section of the taxiway (7), characterized in that the beacon (4) comprises first and second directional transmitting antennas (8a, 8b), respectively outputting first and second directional signals (4a, 5a, 4b, 5b) in respective first and second traffic directions on the taxiway, thereby defining first and second geographical areas of circulation (9a, 9b) different from each other.   Speed limitation system (1) according to claim 1, characterized in that the transmitted signals have a range of at least 10 meters.   3. speed limitation system according to any one of claims 1 and 2, characterized in that the beacon comprises first and second transmitters (10a, 10b) respectively connected to the first and second antennas (8a, 8b) of the beacon .   Speed limitation system according to one of Claims 1 to 3, characterized in that the first directional signals (4a, 5a) indicate a first value representative of the maximum speed not to be exceeded and the second directional signals (4b). , 5b) indicate a second representative value of the limit speed not to be exceeded, the first representative value being different from the second representative value.   Speed limitation system according to any one of claims 1 to 4, characterized in that it comprises at least one receiving device (11) adapted to be loaded on board a vehicle (2), said receiving device (11) being adapted to receive the directional signals (4a, 4b, 5a, 5b) from said at least one transmitting beacon (4, 5), and to interpret said received signals to at least determine a value representative of the current limiting speed not to be exceeded, the device further comprising a memory adapted to store at least said value representative of the current limit speed not to be exceeded.   Speed limitation system (1) according to claim 5, characterized in that said receiving device (11) is provided with information means adapted to indicate to a user of the system the current limit speed value at no not exceed.   Speed limitation system (1) according to any one of claims 5 or 6, characterized in that said receiving device (11) comprises a speed limiting means (12) adapted to automatically limit the actual speed of a vehicle (2) on which the receiver device is embedded, this actual speed being limited by the speed limiting means as a function of said stored current limit value.   8. A method of limiting the speed of a motor vehicle (2) characterized in that it consists of successively.   transmitting, in a given first geographic area (9a) and to the vehicle (2), signals indicating a value representative of the limit speed (6) not to be exceeded and a representative value of maximum distance to be traveled at this speed limit not to exceed; receiving, with the aid of a receiver device (11) on board the vehicle, said signals and interpreting these signals to determine a current limit value of speed not to be exceeded and the value of the maximum distance to be traveled; - record the current limit value of speed not to be exceeded and the value of the maximum distance to be traveled; - evaluate the distance traveled by the vehicle (2) since the registration of said values; - and, as long as the distance traveled by the vehicle since the recording of said values is less than the maximum distance to be traveled, inform the driver of the vehicle the current value of speed not to exceed and / or limit the actual speed of the vehicle by function of the current limit speed value not to be exceeded.