EP0025388A1 - Measuring device for a road traffic parameter and signalling system comprising such a device - Google Patents

Measuring device for a road traffic parameter and signalling system comprising such a device Download PDF

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Publication number
EP0025388A1
EP0025388A1 EP80401243A EP80401243A EP0025388A1 EP 0025388 A1 EP0025388 A1 EP 0025388A1 EP 80401243 A EP80401243 A EP 80401243A EP 80401243 A EP80401243 A EP 80401243A EP 0025388 A1 EP0025388 A1 EP 0025388A1
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Prior art keywords
section
circuit
vehicles
road traffic
length
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EP80401243A
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German (de)
French (fr)
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EP0025388B1 (en
Inventor
Raymond Marcy
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Thales SA
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Thomson CSF SA
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    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/01—Detecting movement of traffic to be counted or controlled
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/07—Controlling traffic signals
    • G08G1/08—Controlling traffic signals according to detected number or speed of vehicles

Definitions

  • the present invention relates to a device for measuring road traffic, and to a signaling system comprising such a device.
  • a signaling system is necessary in order to regulate traffic on this road network.
  • an optical signaling system is used which makes it possible to favor the flow of traffic on one road section rather than another, so as to regularize the traffic in particular at the intersections of streets or high traffic roads or with very different circulation.
  • these signaling systems of the type for example optical
  • This predetermined and fixed value of the passage time of vehicles coming from a determined road section can cause the risk of a traffic jam at this crossroads; traffic conditions change differently during the same day on the sections of track leading to the same crossroads. It is therefore necessary to take into account variations in traffic on the different road sections leading to the same crossroads.
  • the increasing use of heavy and long vehicles such as buses or heavy vehicles semi-trailers, makes it necessary, on the arrival of such a vehicle, to modify the period of the signaling system optics so as to allow them to easily cross this intersection of road sections.
  • the prior art uses devices making it possible to define certain quantities characteristic of road traffic on a given section.
  • the present invention aims to remedy these drawbacks by defining a new parameter directly proportional to the ratio of the spatial density of occupation of a given section by the average speed of the vehicles passing on this section.
  • the device therefore comprises at least two calculation circuits, the first determining the spatial density of occupancy and the average speed of the vehicles passing on this section, the second calculation circuit carrying out the measurement of the arduousness P (t) according to the two preceding variable parameters.
  • Figure 1 shows an embodiment of the device according to the invention for a road section having only one lane. It comprises a first local measurement circuit 1 making it possible to determine the speed and the length of the vehicles entering the road section of length L chosen, a second local measurement circuit 3 located at the exit of the road section of length L, this second circuit local measurement only determining the speed of vehicles leaving the road section.
  • These two local measurement circuits 1 and 3 are respectively connected to two circuits 4 and 8 for determining the average speeds of entry Vem and exit Vsm of the vehicles on the road section II; these two circuits for determining the average input and output speeds 4 and 8 are connected on the one hand to a set of memory circuits, of the shift register type 10, and on the other hand to a circuit 9 for determining the average speed VM of the vehicles over the entire road section 11 of length L.
  • the set of memory circuits of the shift register type 10 is connected to a circuit 12 for determining the spatial occupancy density DE (t).
  • the output of this space occupancy density determination circuit 12 as well that the circuit 9 for determining the average speed VM of the vehicles on the road section 11 are connected to the circuit 20 for calculating the arduousness P (t).
  • the output of this arduousness calculation circuit 20 is connected to an output terminal 21 via a comparator 47.
  • a memory circuit 61 is also connected to the arduousness calculation circuit 20 P (t).
  • the set of memory circuits 10 of the shift register type comprises at least three memory circuits of the shift register type 5, 6, 7 connected in series.
  • the local measurement circuit 1 located at the entrance to the road section 11 of length L, detects the passage of each of the vehicles entering this road section. It then transmits for each vehicle entering the road section 11 on the one hand the speed Vei of this vehicle at the measurement point, on the other hand the length Li of this vehicle, in the form of an uninterrupted succession of binary pulses including the number is directly proportional to the length of the vehicle in question.
  • This succession of binary pulses of unit amplitude is introduced into the set of memory circuits of the shift register type 10 and more particularly into the first memory circuit of the shift register type 5.
  • the propagation speed of the binary word corresponding to a succession of unit binary pulses in this shift type memory register 5 is controlled by a clock circuit not shown here and included in memory circuit 5, the frequency of this clock circuit being directly proportional to the average speed Vem of vehicles entering the road section 11.
  • the transmission speed by successive shifts in the second memory circuit 6 of the binary words represented sensing the length of the vehicles located on the section 11, is controlled by a clock circuit whose frequency is directly proportional to the speed VM previously defined.
  • the third memory circuit 7, also of the shift register type, connected to the output of the second memory circuit 6, is controlled by a clock circuit not shown here, the frequency of which is directly proportional to the average output speed. of the vehicle of the road section 11 considered.
  • the space occupancy density determination circuit 12 continuously measures the ratio between the sum of the lengths Li of each vehicle on the road section, and the length L of this road section. To achieve this result, it continuously receives, in the form of a parallel output from the set of memory circuits 10 of the shift register type, the content of these memory circuits. The total length occupied by the vehicles on this road section is then determined by simple counting of the unit pulses contained in these memory circuits 10. To achieve this result, the circuit 12 for determining the density of spatial occupation may include a circuit of calculation of the microprocessor type making it possible to count and measure the ratio between the sum of the lengths of the vehicles and the length L of the road section 11.
  • the capacity of the memory circuits 5, 6, 7 used depends on the number of binary pulses unit that we are considering to represent a determined length. It is clear that the measurement accuracy of the length of the vehicles on the road section 11 depends directly on the length corresponding to the transmission of a unit pulse by the local measurement circuit 1 and therefore on the frequency d sampling of this local measurement circuit 1. The increase in the measurement accuracy of the length of the vehicles and therefore of the determination of the spatial occupancy density DE (t) also generates an increase in the capacity and therefore of the size and cost of all of the memory circuits 10. The capacity of these memory circuits 10 and therefore the measurement accuracy are thus determined by depending on the road section to which we wish to apply this device.
  • the limitation of the previous embodiment of the device according to the invention to a single channel therefore appears clearly in the above; in fact, the shift registers 5, 6, 7 can only represent the image of vehicles traveling on a single lane and therefore corresponding to traffic on a single lane.
  • the signal DE (t) of the spatial occupancy density from circuit 12 is transmitted in the form of binary words to circuit 20 for calculating the value P (t) of arduousness.
  • the arduousness calculation circuit 20 therefore delivers a value P (t) equal to the ratio of the spatial occupation density DE (t) to the average speed VM of the vehicles on the section L which is renewed at the rate of transmission of the pulses binary of the local measurement circuit 1.
  • This value of the arduousness P (t) is multiplied by a constant ⁇ contained in a memory 61, the role of this constant is to obtain weakest arduousness values to handle.
  • This arduous signal P (t) controls the signaling system, for example of the optical type of a crossroads of a road section. This command can for example be direct, which amounts to saying that the light switching time varies progressively as a function of the values of the arduousness signal P (t).
  • a preferential variant of the control of the signaling system will be done via a comparator 47 permanently comparing the painfulness values P (t) coming from the calculation circuit 20 with predetermined constant coefficients P 0 , P ' 0 contained in a memory that can be included in the comparator 47.
  • This comparator 47 then delivers a control signal to the use system if P (t) is greater than or equal to P o and / or P (t) less than or equal to P ' 0 .
  • P 0 and P ' 0 being numbers whose values are predetermined.
  • Figure 2 shows a second embodiment of the device according to the invention, more particularly usable for a road section of length L multi-ways.
  • the set of calculation circuits 60 in addition to the local measurement circuit 1 identical to that described in the exemplary embodiment of FIG. 1, and delivering the signals corresponding to the length and the speed of the vehicles 2 entering the section road 11, the second local measurement circuit 3 delivering a signal corresponding to the exit speed of vehicles 2 from the road section 11, comprises two circuits 32 and 33 for determining the average speed of entry and exit of vehicles on the section road, these two circuits 32 and 33 for determining the average input and output speeds being controlled by a clock circuit 31 determining the time T during which the average speeds are calculated.
  • the outputs of these two circuits for calculating the average input and output values 32 and 33 are connected to a circuit 34 calculating the average speed VM of the vehicles on the defined road section 11 by the half-sum of the average values of entry and exit of the vehicles on the road section 11, coming from the two calculation circuits 32, 33 of these average values.
  • the output of this circuit 34 for determining the average speed VM on the road section 11 is connected to a comparator 36 also connected to a memory circuit 37, comparing the value of this average speed with a predetermined threshold V 0 .
  • the output of the comparator 36 is connected, on the one hand to the arduousness calculation circuit 20, and on the other hand to a circuit 38 performing the ratio of the length L of the road section 11, contained in a memory 39, with the VM value of the average vehicle speed on this section.
  • the value T of this ratio is applied to a set of controlled switches 40.
  • This set of controlled switches 40 also receives from the local measurement circuit 1, the signals corresponding to the length of the vehicles entering the road section 11.
  • This set of controlled switches 40 is connected to a multiplexer 45 by means of a set of N summing circuits 41, identical.
  • a clock circuit 35 is connected to the control inputs, on the one hand of the set of controlled switches 40 and on the other hand, of the multiplexer 45.
  • the output of this multiplexer 45 is connected to a calculation circuit 70 of the spatial occupation density of the road section 11, this circuit 70 also being connected to the memory circuit 39 containing the value L of the length of the road section 11.
  • the output of this circuit 70 is connected to the circuit 20 for calculating the arduousness P (t).
  • the circuit 34 delivers from the values Vme and Vms average speeds of entry and exit of vehicles 2 of the road section 11, the value VM calculated as above average speed vehicles 2 on the road section 11.
  • a first test is made at the output of this circuit by the comparator 36, making it possible to trigger an alarm if the average speed VM is less than a predetermined threshold V 0 . This alarm signal is available at a terminal 80.
  • the circuit 38 calculates the time T 0 corresponding to the time taken by a vehicle 2 to travel the road section 11.
  • Each summing circuit 41 will then receive the signals corresponding to the lengths of the vehicles from the first local measurement circuit 1, during this time T0.
  • the time intervals T 0 during which each summing circuit 41 performs the sum of the lengths Li corresponding to the vehicles entering the section 11, are offset with respect to each other, for each summing circuit 41 by an equal value.
  • the time interval of length T 0 during which one of the summing circuits 41 will perform the sum of the signals corresponding to the lengths of the vehicles entering the road section 11, is offset from the time interval T 0 during which the summation circuit 41 next will perform the summation of the lengths of the vehicles 2 entering the section 11, for a time equal to T 1 .
  • N represents the number of summing circuits 41 connected between the set of controlled switches 40 and the multiplexer 45, this number N of summing circuits 41 is defined by:
  • the first summing circuit 41 begins again to sum the lengths Li of the vehicles 2 entering the section 11.
  • a cyclic summation is thus obtained during time intervals of constant lengths equal to T 0 , offset from one another by a constant time interval T 1 , depending on the number N of summing circuits 41 which are available between l set of controlled switches 40 and the multiplexer 45.
  • This number N thus determines the frequency of renewal of the information of the measurement of the spatial occupation density DE (t), available at the output of the multiplexer 45.
  • the output of the multiplexer 45 delivers at the rate of the signals from the clock circuit 35, the results of the different summations carried out during time intervals T 0 , of the lengths of the vehicles entering the section 11.
  • the value of the spatial density of occupation DE (t) is determined by a circuit 70 receiving on the one hand, the length L of the section 11 coming from a memory circuit 39, and on the other hand, the signals coming from the multiplexer 45.
  • the calculation of the arduousness P (t) is then done in the same way so that for the device described in FIG. 1.
  • Its use for controlling a signaling system can be done either by means of a comparator 47 as described above, or by the intermediate of a computing circuit 48 transforming the fo nction of the time (t) of the arduous P (t) into a function F (t), this function F being chosen so as to obtain a quasi-linear variation of the arduous function P (t) when the traffic conditions on the section 11 vary.
  • the signals from this circuit 48 can then either directly control the optical signaling system, or control this same optical signaling system but via a comparator not shown here and similar to the comparator 47 described above.
  • circuit 60 calculating from the local measurement circuits 1 and 3, on the one hand the value of the spatial occupation density DE (t), and on the other hand the average speed VM of the vehicles on the stretch road 11.
  • the circuit 12 for determining the density of spatial occupancy can directly deliver a control signal to the signaling system, for example of the optical type, in the case where one of the vehicles represented by the succession of a set of unit binary pulses, corresponds to a greater length and / or equal to a predetermined value permanently stored in a memory included in the circuit 12 for determining the density of spatial occupancy.
  • a control signal to the signaling system, for example of the optical type, in the case where one of the vehicles represented by the succession of a set of unit binary pulses, corresponds to a greater length and / or equal to a predetermined value permanently stored in a memory included in the circuit 12 for determining the density of spatial occupancy.
  • This can be particularly advantageous in the case of a road section over which many heavy vehicles, for example of the bus or truck type are required to pass.
  • the control of the signaling system for example of the optical type, controlled by measuring the arduousness function of this road section can then be doubly controlled, on the one hand by the value of this arduousness function, on the other hand by the signal from circuit 12 for determining the density of spatial occupancy generated at the arrival of a heavy vehicle or of considerable length.
  • a device for measuring road traffic and a signaling system, more particularly of the optical type, comprising such a device have thus been described.

Abstract

L'invention concerne les dispositifs permettant la mesure du trafic routier sur un tronçon de longueur déterminée. L'utilisation d'un paramètre de pénibilité égal au rapport de la densité d'occupation spatiale et de la vitesse moyenne des véhicules sur le tronçon considéré permet d'éviter les ambiguïtés dues à l'évaluation du trafic à l'aide de l'un seulement des deux paramètres. Elle s'applique à tous les systèmes de signalisation routière et plus particulièrement à ceux du type optique.The invention relates to devices for measuring road traffic over a section of determined length. The use of an arduousness parameter equal to the ratio of the density of space occupation and the average speed of the vehicles on the section considered makes it possible to avoid ambiguities due to the evaluation of traffic using only one of the two parameters. It applies to all road signaling systems and more particularly to those of the optical type.

Description

La présente invention concerne un dispositif de mesure du trafic routier, et un système de signalisation comportant un tel dispositif.The present invention relates to a device for measuring road traffic, and to a signaling system comprising such a device.

A certains endroits du réseau routier, et en particulier dans les villes, un système de signalisation est nécessaire afin de régulariser la circulation sur ce réseau routier. Pour ce faire, on utilise par exemple un système de signalisation optique permettant de favoriser l'écoulement du trafic sur un tronçon routier plutôt que sur un autre, de façon à régulariser le trafic en particulier aux intersections de rues ou de routes à grande circulation ou à circulation très différente.In certain places on the road network, and in particular in cities, a signaling system is necessary in order to regulate traffic on this road network. To do this, for example, an optical signaling system is used which makes it possible to favor the flow of traffic on one road section rather than another, so as to regularize the traffic in particular at the intersections of streets or high traffic roads or with very different circulation.

Selon l'art antérieur, ces systèmes de signalisation du type, par exemple optique, ont des périodes de répétition fixes. Cette valeur prédéterminée et fixe du temps de passage des véhicules provenant d'un tronçon routier déterminé, peut provoquer des risques d'embouteillage à ce carrefour ; en effet, les conditions de circulation évoluent différemment au cours d'une même journée sur les tronçons de voie aboutissant à un même carrefour. Il est donc nécessaire de tenir compte des variations de trafic sur les différents tronçons routiers aboutissant à un même carrefour. D'autre part, l'utilisation de plus en plus importante de véhicules lourds et longs du type autobus ou poids lourds semi-remorques, rend nécessaire, à l'arrivée d'un tel véhicule, la modification de la période du système de signalisation optique de façon à leur permettre une traversée aisée de cette intersection de tronçons routiers.According to the prior art, these signaling systems of the type, for example optical, have fixed repetition periods. This predetermined and fixed value of the passage time of vehicles coming from a determined road section, can cause the risk of a traffic jam at this crossroads; traffic conditions change differently during the same day on the sections of track leading to the same crossroads. It is therefore necessary to take into account variations in traffic on the different road sections leading to the same crossroads. On the other hand, the increasing use of heavy and long vehicles such as buses or heavy vehicles semi-trailers, makes it necessary, on the arrival of such a vehicle, to modify the period of the signaling system optics so as to allow them to easily cross this intersection of road sections.

Pour remédier à cet inconvénient, l'art antérieur utilise des dispositifs permettant de définir certaines grandeurs caractéristiques du trafic routier sur un tronçon donné.To overcome this drawback, the prior art uses devices making it possible to define certain quantities characteristic of road traffic on a given section.

Les plus utilisées, du fait de leur simplicité de mesure, correspondent au débit de véhicules par unité de temps, à la vitesse moyenne des véhicules passant à un point donné, à la concentration des véhicules sur un tronçon donné, au taux d'occupation par les véhicules passant par ce tronçon. La commande directe des systèmes de signalisation optique, par exemple à une intersection de tronçon routier, en fonction des valeurs obtenues pour la mesure des paramètres précédents, présente de nombreux inconvénients. Des mesures ont été faites en réseau urbain sur des tronçons supportant des trafics très différents. Cette comparaison étant fondée sur les mesures de la vitesse, du débit, de la concentration ou du taux d'occupation par exemple, la valeur moyenne des écarts obtenus pour la commande de signalisation de l'intersection du tronçon routier était faible. Ceci montre qu'il existe des ambiguités, pouvant être très gênantes, si l'on considère uniquement l'un des paramètres précédents.The most used, due to their simplicity of measurement, correspond to the speed of vehicles per unit of time, to the average speed of vehicles passing at a given point, to the concentration vehicles on a given section, at the rate of occupancy by vehicles passing through this section. The direct control of optical signaling systems, for example at an intersection of a road section, as a function of the values obtained for the measurement of the preceding parameters, has many disadvantages. Measurements were made in the urban network on sections supporting very different traffics. This comparison being based on measurements of speed, flow, concentration or occupancy rate for example, the average value of the deviations obtained for the signaling control of the intersection of the road section was low. This shows that there are ambiguities, which can be very annoying, if we consider only one of the previous parameters.

La présente invention vise à remédier à ces inconvénients en définissant un nouveau paramètre directement proportionnel au rapport de la densité spatiale d'occupation d'un tronçon donné par la vitesse moyenne des véhicules, passant sur ce tronçon.The present invention aims to remedy these drawbacks by defining a new parameter directly proportional to the ratio of the spatial density of occupation of a given section by the average speed of the vehicles passing on this section.

Selon une caractéristique principale de l'invention, le dispositif de mesure du trafic routier sur un tronçon de longueur L, comporte un premier circuit de calcul délivrant d'une part un signal DE(t) correspondant à la densité d'occupation spatiale de ce tronçon en fonction du temps, égale au quotient de la somme des longueurs Li des différents véhicules se trouvant sur ce tronçon, par la longueur L de ce tronçon, et d'autre part un signal VM correspondant à la vitesse moyenne des véhicules sur ce- tronçon calculée sur un temps prédéterminé T, un second circuit de calcul délivrant le signal P(t) = α. DE(t)/VM, où α est une constante prédéterminée, commandant au moins les signaux situés sur et/ou à proximité de ce tronçon routier.According to a main characteristic of the invention, the device for measuring road traffic over a section of length L, comprises a first calculation circuit delivering on the one hand a signal DE (t) corresponding to the spatial occupation density of this section as a function of time, equal to the quotient of the sum of the lengths Li of the different vehicles on this section, by the length L of this section, and on the other hand a signal VM corresponding to the average speed of the vehicles on this section calculated over a predetermined time T, a second calculation circuit delivering the signal P (t) = α. DE (t) / VM, where α is a predetermined constant, controlling at least the signals located on and / or near this road section.

D'autres avantages et caractéristiques de l'invention ressortiront de la description qui suit de deux exemples de réalisation donnée à l'aide des figures qui représentent :

  • - la figure 1, un exemple de réalisation du dispositif selon l'invention
  • - la figure 2, un second exemple de réalisation du dispositif selon l'invention.
Other advantages and characteristics of the invention will emerge from the description which follows of two exemplary embodiments given with the aid of the figures which represent:
  • - Figure 1, an embodiment of the device according to the invention
  • - Figure 2, a second embodiment of the device according to the invention.

Comme il a été dit précédemment le procédé mis en oeuvre par le dispositif selon l'invention, utilise un paramètre variable P(t) que l'on appelera dans la suite de la description la pénibilité et qui est définie par :

  • P(t) = DE(t)/VM,

où DE(t) correspond à la mesure de la densité spatiale d'occupation d'un tronçon donné de longueur L en fonction du temps t et VM la vitesse moyenne des véhicules passant sur ce tronçon de longueur L.As has been said previously, the method implemented by the device according to the invention, uses a variable parameter P (t) which will be called in the following description the arduousness and which is defined by:
  • P (t) = DE (t) / VM,

where DE (t) corresponds to the measurement of the spatial density of occupation of a given section of length L as a function of time t and VM the average speed of the vehicles passing on this section of length L.

Le dispositif selon l'invention comporte donc au moins deux circuits de calcul, le premier déterminant la densité spatiale d'occupation et la vitesse moyenne des véhicules passant sur ce tronçon, le deuxième circuit de calcul effectuant la mesure de la pénibilité P(t) en fonction des deux paramètres variables précédents.The device according to the invention therefore comprises at least two calculation circuits, the first determining the spatial density of occupancy and the average speed of the vehicles passing on this section, the second calculation circuit carrying out the measurement of the arduousness P (t) according to the two preceding variable parameters.

La figure 1 montre un exemple de réalisation du dispositif selon l'invention pour un tronçon routier ne comportant qu'une seule voie. Il comporte un premier circuit de mesure locale 1 permettant de déterminer la vitesse et la longueur des véhicules entrant sur le tronçon routier de longueur L choisi, un second circuit de mesure locale 3 situé à la sortie du tronçon routier de longueur L, ce second circuit de mesure locale ne déterminant que la vitesse des véhicules sortant du tronçon routier. Ces deux circuits de mesure locale 1 et 3 sont respectivement connectés à deux circuits 4 et 8 de détermination des vitesses moyennes d'entrée Vem et de sortie Vsm des véhicules sur le tronçon routier Il ; ces deux circuits de détermination des vitesses moyennes d'entrée et de sortie 4 et 8 sont connectés d'une part à un ensemble de circuits mémoire, du type registre à décalage 10, et d'autre part à un circuit de détermination 9 de la vitesse moyenne VM des véhicules sur l'ensemble du tronçon routier 11 de longueur L. L'ensemble de circuits mémoire du type registre à décalage 10, est connecté à un circuit 12 de détermination de la densité d'occupation spatiale DE(t). La sortie de ce circuit de détermination de la densité d'occupation spatiale 12 ainsi que le circuit 9 de détermination de la vitesse moyenne VM des véhicules sur le tronçon routier 11 sont connectés au circuit de calcul 20 de la pénibilité P(t). La sortie de ce circuit 20 de calcul de la pénibilité est connectée à une borne de sortie 21 par l'intermédiaire d'un comparateur 47. Un circuit mémoire 61 est également connecté au circuit 20 de calcul de la pénibilité P(t). L'ensemble de circuits mémoire 10 du type registre à décalage comporte au moins trois circuits de mémoire du type registre à décalage 5, 6, 7 connectés en série.Figure 1 shows an embodiment of the device according to the invention for a road section having only one lane. It comprises a first local measurement circuit 1 making it possible to determine the speed and the length of the vehicles entering the road section of length L chosen, a second local measurement circuit 3 located at the exit of the road section of length L, this second circuit local measurement only determining the speed of vehicles leaving the road section. These two local measurement circuits 1 and 3 are respectively connected to two circuits 4 and 8 for determining the average speeds of entry Vem and exit Vsm of the vehicles on the road section II; these two circuits for determining the average input and output speeds 4 and 8 are connected on the one hand to a set of memory circuits, of the shift register type 10, and on the other hand to a circuit 9 for determining the average speed VM of the vehicles over the entire road section 11 of length L. The set of memory circuits of the shift register type 10, is connected to a circuit 12 for determining the spatial occupancy density DE (t). The output of this space occupancy density determination circuit 12 as well that the circuit 9 for determining the average speed VM of the vehicles on the road section 11 are connected to the circuit 20 for calculating the arduousness P (t). The output of this arduousness calculation circuit 20 is connected to an output terminal 21 via a comparator 47. A memory circuit 61 is also connected to the arduousness calculation circuit 20 P (t). The set of memory circuits 10 of the shift register type comprises at least three memory circuits of the shift register type 5, 6, 7 connected in series.

Le circuit de mesure locale 1 situé à l'entrée du tronçon routier 11 de longueur L, détecte le passage de chacun des véhicules entrant sur ce tronçon routier. Il transmet alors pour chaque véhicule entrant sur le tronçon routier 11 d'une part la vitesse Vei de ce véhicule au point de mesure, d'autre part la longueur Li de ce véhicule, sous forme d'une succession ininterrompue d'impulsions binaires dont le nombre est directement proportionnel à la longueur du véhicule considéré. Cette succession d'impulsions binaires d'amplitude unité est introduite dans l'ensemble de circuits mémoire du type registre à décalage 10 et plus particulièrement dans le premier circuit mémoire du type registre à décalage 5. La vitesse de propagation du mot binaire correspondant à une succession d'impulsions binaires unité dans ce registre mémoire du type à décalage 5 est commandée par un circuit d'horloge non représenté ici et compris dans le circuit mémoire 5, la fréquence de ce circuit d'horloge étant directement proportionnelle à la vitesse moyenne Vem des véhicules à l'entrée du tronçon routier 11. La valeur de la vitesse moyenne d'entrée des véhicules sur le tronçon routier 11 déterminée par le circuit 4, ainsi que la valeur de la vitesse moyenne de sortie de ces mêmes véhicules du tronçon routier 11 déterminée par le circuit 8, sont appliquées au circuit 9 de détermination de la vitesse moyenne VM des véhicules sur l'ensemble du tronçon routier Il ; cette valeur VM moyenne est définie par : VM = (Vem + Vsm)/2. La vitesse de transmission par décalages successifs dans le second circuit mémoire 6 des mots binaires représentant la longueur des véhicules situés sur le tronçon 11, est commandée par un circuit d'horloge dont la fréquence est directement proportionnelle à la vitesse VM précédemment définie. De même, le troisième circuit mémoire 7, également du type registre à décalage, connecté à la sortie du second circuit mémoire 6, est commandé par un circuit d'horloge non représenté ici, dont la fréquence est directement proportionnelle à la vitesse moyenne de sortie du véhicule du tronçon routier 11 considéré.The local measurement circuit 1 located at the entrance to the road section 11 of length L, detects the passage of each of the vehicles entering this road section. It then transmits for each vehicle entering the road section 11 on the one hand the speed Vei of this vehicle at the measurement point, on the other hand the length Li of this vehicle, in the form of an uninterrupted succession of binary pulses including the number is directly proportional to the length of the vehicle in question. This succession of binary pulses of unit amplitude is introduced into the set of memory circuits of the shift register type 10 and more particularly into the first memory circuit of the shift register type 5. The propagation speed of the binary word corresponding to a succession of unit binary pulses in this shift type memory register 5 is controlled by a clock circuit not shown here and included in memory circuit 5, the frequency of this clock circuit being directly proportional to the average speed Vem of vehicles entering the road section 11. The value of the average speed of entry of vehicles on the road section 11 determined by circuit 4, as well as the value of the average speed of exit of these same vehicles from the road section 11 determined by circuit 8, are applied to circuit 9 for determining the average speed VM of vehicles over the entire road section II; this average VM value is defined by: VM = (Vem + Vsm) / 2. The transmission speed by successive shifts in the second memory circuit 6 of the binary words represented sensing the length of the vehicles located on the section 11, is controlled by a clock circuit whose frequency is directly proportional to the speed VM previously defined. Likewise, the third memory circuit 7, also of the shift register type, connected to the output of the second memory circuit 6, is controlled by a clock circuit not shown here, the frequency of which is directly proportional to the average output speed. of the vehicle of the road section 11 considered.

Le circuit de détermination de la densité d'occupation spatiale 12, mesure en permanence le rapport entre la somme des longueurs Li de chaque véhicule se trouvant sur le tronçon routier, et la longueur L de ce tronçon routier. Pour arriver à ce résultat, elle reçoit en permanence, sous forme d'une sortie parallèle de l'ensemble de circuits mémoire 10 du type registre à décalage, le contenu de ces circuits mémoire. La longueur totale occupée par les véhicules sur ce tronçon routier est alors déterminée par simple comptage des impulsions unité contenues dans ces circuits mémoire 10. Pour arriver à ce résultat, le circuit 12 de détermination de la densité d'occupation spatiale peut comporter un circuit de calcul du type microprocesseur permettant d'effectuer le comptage et la mesure du rapport entre la somme des longueurs des véhicules et la longueur L du tronçon routier 11. La capacité des circuits mémoire 5, 6, 7 utilisés dépend du nombre d'impulsions binaire unité que l'on envisage pour représenter une longueur déterminée. Il est clair que la précision de mesure de la longueur des véhicules se trouvant sur le tronçon routier 11, dépend directement de la longueur correspondant à la transmission d'une impulsion unité par le circuit de mesure locale 1 et par conséquent, de la fréquence d'échantillonnage de ce circuit de mesure locale 1. L'accroissement de la précision de mesure de la longueur des véhicules et donc de la détermination de la densité d'occupation spatiale DE(t) engendre également une augmentation de la capacité et donc de l'encombrement et du CoÛt de l'ensemble des circuits mémoire 10. La capacité de ces circuits mémoire 10 et donc la précision de mesure sont ainsi déterminées en fonction du tronçon routier auquel on désire appliquer ce dispositif.The space occupancy density determination circuit 12 continuously measures the ratio between the sum of the lengths Li of each vehicle on the road section, and the length L of this road section. To achieve this result, it continuously receives, in the form of a parallel output from the set of memory circuits 10 of the shift register type, the content of these memory circuits. The total length occupied by the vehicles on this road section is then determined by simple counting of the unit pulses contained in these memory circuits 10. To achieve this result, the circuit 12 for determining the density of spatial occupation may include a circuit of calculation of the microprocessor type making it possible to count and measure the ratio between the sum of the lengths of the vehicles and the length L of the road section 11. The capacity of the memory circuits 5, 6, 7 used depends on the number of binary pulses unit that we are considering to represent a determined length. It is clear that the measurement accuracy of the length of the vehicles on the road section 11 depends directly on the length corresponding to the transmission of a unit pulse by the local measurement circuit 1 and therefore on the frequency d sampling of this local measurement circuit 1. The increase in the measurement accuracy of the length of the vehicles and therefore of the determination of the spatial occupancy density DE (t) also generates an increase in the capacity and therefore of the size and cost of all of the memory circuits 10. The capacity of these memory circuits 10 and therefore the measurement accuracy are thus determined by depending on the road section to which we wish to apply this device.

La limitation de l'exemple précédent de réalisation du dispositif selon l'invention à une seule voie apparaît donc clairement dans ce qui précède ; en effet, les registres à décalage 5, 6, 7 ne peuvent que représenter l'image de véhicules circulant sur une seule file et donc correspondant à un trafic sur une seule voie. Le signal DE(t) de la densité d'occupation spatiale issu du circuit 12, est transmis sous forme de mots binaires au circuit 20 de calcul de la valeur P(t) de la pénibilité. Le circuit de calcul 20 de la pénibilité délivre donc une valeur P(t) égale au rapport de la densité d'occupation spatiale DE(t) sur la vitesse moyenne VM des véhicules sur le tronçon L qui est renouvelé au rythme de transmission des impulsions binaire du circuit de mesure locale 1. Cette valeur de la pénibilité P(t) est multipliée par une constante α contenue dans une mémoire 61, le rôle de cette constante est d'obtenir des valeurs de pénibilité plus faible à manipuler. Une valeur préférentielle de cette constante Cc est telle que ex = 10. Ce signal de pénibilité P(t) commande le système de signalisation par exemple du type optique d'un carrefour de tronçon routier. Cette commande peut être par exemple directe, ce qui revient à dire que le temps de permutation des feux varie progressivement en fonction des valeurs du signal de pénibilité P(t).The limitation of the previous embodiment of the device according to the invention to a single channel therefore appears clearly in the above; in fact, the shift registers 5, 6, 7 can only represent the image of vehicles traveling on a single lane and therefore corresponding to traffic on a single lane. The signal DE (t) of the spatial occupancy density from circuit 12 is transmitted in the form of binary words to circuit 20 for calculating the value P (t) of arduousness. The arduousness calculation circuit 20 therefore delivers a value P (t) equal to the ratio of the spatial occupation density DE (t) to the average speed VM of the vehicles on the section L which is renewed at the rate of transmission of the pulses binary of the local measurement circuit 1. This value of the arduousness P (t) is multiplied by a constant α contained in a memory 61, the role of this constant is to obtain weakest arduousness values to handle. A preferential value of this constant Cc is such that e x = 10. This arduous signal P (t) controls the signaling system, for example of the optical type of a crossroads of a road section. This command can for example be direct, which amounts to saying that the light switching time varies progressively as a function of the values of the arduousness signal P (t).

Une variante préférentielle de la commande du système de signalisation, se fera par l'intermédiaire d'un comparateur 47 comparant en permanence les valeurs de la pénibilité P(t) issues du circuit de calcul 20 avec des coefficients constants prédéterminés P0, P'0 contenus dans une mémoire pouvant être comprise dans le comparateur 47. Ce comparateur 47 délivre alors un signal de commande au système d'utilisation si P(t) est supérieur ou égal à Po et/ou P(t) inférieur ou égal à P'0. P0 et P'0 étant des nombres dont les valeurs sont prédéterminées. Ce dernier mode de commande du système de signalisation est plus simple et s'adapte plus facilement aux systèmes existants de signalisation, par exemple du type optique.A preferential variant of the control of the signaling system will be done via a comparator 47 permanently comparing the painfulness values P (t) coming from the calculation circuit 20 with predetermined constant coefficients P 0 , P ' 0 contained in a memory that can be included in the comparator 47. This comparator 47 then delivers a control signal to the use system if P (t) is greater than or equal to P o and / or P (t) less than or equal to P ' 0 . P 0 and P ' 0 being numbers whose values are predetermined. This latter mode of control of the signaling system is simpler and more easily adapted to existing signaling systems, for example of the optical type.

La figure 2 représente un second exemple de réalisation du dispositif selon l'invention, plus particulièrement utilisable pour un tronçon routier de longueur L multivoies.Figure 2 shows a second embodiment of the device according to the invention, more particularly usable for a road section of length L multi-ways.

Il comporte un ensemble de circuits 60 permettant, à partir des mesures aux deux extrémités d'un tronçon routier 11 de longueur L, de déterminer la longueur et la vitesse d'entrée et de sortie des véhicules 2 sur le tronçon routier 11, et d'en déduire la valeur de la densité d'occupation spatiale DE(t) ainsi que la vitesse moyenne des véhicules VM sur ce tronçon routier 11. Un circuit 20 de calcul de la pénibilité P(t), connecté à une mémoire 61 contenant la valeur du coefficient α, délivre le signal de la pénibilité P(t) défini par :

  • P(t) = α DE(t)/VM

Ce signal est transmis à un comparateur 47 identique à celui décrit dans l'exemple de réalisation de la figure 1 et à un circuit de calcul 48, délivrant à une borne d'utilisation 50 le signal correspondant à la fonction F(P(t)). Un circuit mémoire 62 dans lequel sont stockées les valeurs Po et P'O des seuils prédéterminés, est connecté à une des entrées du comparateur 47. De façon préférentielle, mais non limitative, le circuit 48 recevant le signal de pénibilité P(t) délivre à la borne d'utilisation 50 le signal correspondant à la fonction log (1 + P(t)). La fonction √Pt(t) peut également être employée.It comprises a set of circuits 60 making it possible, from measurements at the two ends of a road section 11 of length L, to determine the length and the speed of entry and exit of the vehicles 2 on the road section 11, and d 'deduce the value of the spatial occupation density DE (t) as well as the average speed of the vehicles VM on this road section 11. A circuit 20 for calculating the arduousness P (t), connected to a memory 61 containing the value of the coefficient α, delivers the painfulness signal P (t) defined by:
  • P (t) = α DE (t) / VM

This signal is transmitted to a comparator 47 identical to that described in the embodiment of FIG. 1 and to a calculation circuit 48, delivering to a use terminal 50 the signal corresponding to the function F (P (t) ). A memory circuit 62 in which the values Po and P ' O of the predetermined thresholds are stored, is connected to one of the inputs of the comparator 47. Preferably, but not limited to, the circuit 48 receiving the painfulness signal P (t) delivers at terminal 50 the signal corresponding to the log function (1 + P (t)). The function √Pt (t) can also be used.

L'ensemble de circuits de calcul 60, outre le circuit de mesure locale 1 identique à celui décrit dans l'exemple de réalisation de la figure 1, et délivrant les signaux correspondant à la longueur et à la vitesse des véhicules 2 rentrant sur le tronçon routier 11, le second circuit de mesure locale 3 délivrant un signal correspondant à la vitesse de sortie des véhicules 2 du tronçon routier 11, comporte deux circuits 32 et 33 de détermination de la vitesse moyenne d'entrée et de sortie des véhicules sur le tronçon routier, ces deux circuits 32 et 33 de détermination des vitesses moyennes d'entrée et de sortie étant commandés par un circuit d'horloge 31 déterminant le temps T pendant lequel les vitesses moyennes sont calculées. Les sorties de ces deux circuits de calcul des valeurs moyennes d'entrée et de sortie 32 et 33 sont connectées à un circuit 34 calculant la vitesse moyenne VM des véhicules sur le tronçon routier 11 définie par la demi-somme des valeurs moyennes d'entrée et de sortie des véhicules sur le tronçon routier 11, issues des deux circuits de calcul 32, 33 de ces valeurs moyennes. La sortie de ce circuit 34 de détermination de la vitesse VM moyenne sur le tronçon routier 11, est connectée à un comparateur 36 également connecté à un circuit mémoire 37, comparant la valeur de cette vitesse moyenne à un seuil V0 prédéterminé.The set of calculation circuits 60, in addition to the local measurement circuit 1 identical to that described in the exemplary embodiment of FIG. 1, and delivering the signals corresponding to the length and the speed of the vehicles 2 entering the section road 11, the second local measurement circuit 3 delivering a signal corresponding to the exit speed of vehicles 2 from the road section 11, comprises two circuits 32 and 33 for determining the average speed of entry and exit of vehicles on the section road, these two circuits 32 and 33 for determining the average input and output speeds being controlled by a clock circuit 31 determining the time T during which the average speeds are calculated. The outputs of these two circuits for calculating the average input and output values 32 and 33 are connected to a circuit 34 calculating the average speed VM of the vehicles on the defined road section 11 by the half-sum of the average values of entry and exit of the vehicles on the road section 11, coming from the two calculation circuits 32, 33 of these average values. The output of this circuit 34 for determining the average speed VM on the road section 11 is connected to a comparator 36 also connected to a memory circuit 37, comparing the value of this average speed with a predetermined threshold V 0 .

La sortie du comparateur 36 est connectée, d'une part au circuit de calcul de la pénibilité 20, et d'autre part à un circuit 38 effectuant le rapport de la longueur L du tronçon routier 11, contenu dans une mémoire 39, avec la valeur VM de la vitesse moyenne des véhicules sur ce tronçon. La valeur T de ce rapport est appliquée à un ensemble d'interrupteurs commandés 40. Cet ensemble d'interrupteurs commandés 40 reçoit également du circuit de mesure locale 1, les signaux correspondant à la longueur des véhicules entrant sur le tronçon routier 11. Cet ensemble d'interrupteurs commandé 40 est connecté à un multiplexeur 45 par l'intermédiaire d'un ensemble de N circuits de sommation 41, identiques. Un circuit d'horloge 35 est connecté aux entrées de commande, d'une part de l'ensemble d'interrupteurs commandés 40 et d'autre part, du multiplexeur 45. La sortie de ce multiplexeur 45 est connectée à un circuit 70 de calcul de la densité d'occupation spatiale du tronçon routier 11, ce circuit 70 étant également connecté au circuit mémoire 39 contenant la valeur L de la longueur du tronçon routier 11. La sortie de ce circuit 70, est connectée au circuit 20 de calcul de la pénibilité P(t).The output of the comparator 36 is connected, on the one hand to the arduousness calculation circuit 20, and on the other hand to a circuit 38 performing the ratio of the length L of the road section 11, contained in a memory 39, with the VM value of the average vehicle speed on this section. The value T of this ratio is applied to a set of controlled switches 40. This set of controlled switches 40 also receives from the local measurement circuit 1, the signals corresponding to the length of the vehicles entering the road section 11. This set of controlled switches 40 is connected to a multiplexer 45 by means of a set of N summing circuits 41, identical. A clock circuit 35 is connected to the control inputs, on the one hand of the set of controlled switches 40 and on the other hand, of the multiplexer 45. The output of this multiplexer 45 is connected to a calculation circuit 70 of the spatial occupation density of the road section 11, this circuit 70 also being connected to the memory circuit 39 containing the value L of the length of the road section 11. The output of this circuit 70, is connected to the circuit 20 for calculating the arduousness P (t).

Les circuits de mesure locale 1 et 3 situés aux extrémités du tronçon routier 11, délivrent les valeurs des vitesses d'entrée et de sortie de ce tronçon routier 11, des différents véhicules 2. Les circuits 32 et 33, commandés par le circuit d'horloge 35, déterminent la vitesse moyenne d'entrée et de sortie de ces véhicules 2. Le circuit 34 délivre à partir des valeurs Vme et Vms des vitesses moyennes d'entrée et de sortie des véhicules 2 du tronçon routier 11, la valeur VM calculée comme précédemment de la vitesse moyenne des véhicules 2 sur le tronçon routier 11. Un premier test est fait à la sortie de ce circuit par le comparateur 36, permettant de déclencher une alarme si la vitesse moyenne VM est inférieure à un seuil V0 prédéterminé. Ce signal d'alarme est disponible à une borne 80. Ensuite le circuit 38 calcule le temps T0 correspondant au temps mis par un véhicule 2 pour parcourir le tronçon routier 11. Chaque circuit de sommation 41 va alors recevoir les signaux correspondant aux longueurs des véhicules issus du premier circuit de mesure locale 1, pendant ce temps T0. Les intervalles de temps T0 pendant lesquels chaque circuit de sommation 41 effectue la somme des longueurs Li correspondant aux véhicules entrant sur le tronçon 11, sont décalés les uns par rapport aux autres, pour chaque circuit de sommation 41 d'une valeur égale. L'intervalle de temps de longueur T0 pendant lequel l'un des circuits de sommation 41 va effectuer la somme des signaux correspondant aux longueurs des véhicules pénétrant sur le tronçon routier 11, est décalé de l'intervalle de temps T0 pendant lequel le circuit de sommation 41 suivant va effectuer la sommation des longueurs des véhicules 2 rentrant sur le tronçon 11, d'un temps égal à T1. Si N représente le nombre de circuits de sommation 41 connecté entre l'ensemble d'interrupteurs commandés 40 et le multiplexeur 45, ce nombre N de circuits de sommation 41 est défini par :

Figure imgb0001
The local measurement circuits 1 and 3 located at the ends of the road section 11, deliver the values of the entry and exit speeds of this road section 11, of the different vehicles 2. The circuits 32 and 33, controlled by the circuit clock 35, determine the average speed of entry and exit of these vehicles 2. The circuit 34 delivers from the values Vme and Vms average speeds of entry and exit of vehicles 2 of the road section 11, the value VM calculated as above average speed vehicles 2 on the road section 11. A first test is made at the output of this circuit by the comparator 36, making it possible to trigger an alarm if the average speed VM is less than a predetermined threshold V 0 . This alarm signal is available at a terminal 80. Then the circuit 38 calculates the time T 0 corresponding to the time taken by a vehicle 2 to travel the road section 11. Each summing circuit 41 will then receive the signals corresponding to the lengths of the vehicles from the first local measurement circuit 1, during this time T0. The time intervals T 0 during which each summing circuit 41 performs the sum of the lengths Li corresponding to the vehicles entering the section 11, are offset with respect to each other, for each summing circuit 41 by an equal value. The time interval of length T 0 during which one of the summing circuits 41 will perform the sum of the signals corresponding to the lengths of the vehicles entering the road section 11, is offset from the time interval T 0 during which the summation circuit 41 next will perform the summation of the lengths of the vehicles 2 entering the section 11, for a time equal to T 1 . If N represents the number of summing circuits 41 connected between the set of controlled switches 40 and the multiplexer 45, this number N of summing circuits 41 is defined by:
Figure imgb0001

Ainsi, après un temps T1, mesuré à partir de l'instant où le dernier circuit de sommation 41 commence la sommation des signaux correspondant aux longueurs des véhicules rentrant sur le tronçon 11, le premier circuit de sommation 41 recommence à effectuer la somme des longueurs Li des véhicules 2 entrant sur le tronçon 11.Thus, after a time T 1 , measured from the moment when the last summing circuit 41 begins summing the signals corresponding to the lengths of the vehicles entering the section 11, the first summing circuit 41 begins again to sum the lengths Li of the vehicles 2 entering the section 11.

On obtient ainsi une sommation cyclique pendant des intervalles de temps de longueurs constantes égales à T0, décalés les uns par rapport aux autres d'un intervalle de temps constant T1, dépendant du nombre N de circuits de sommation 41 dont on dispose entre l'ensemble d'interrupteurs commandés 40 et le multiplexeur 45. Ce nombre N détermine ainsi la fréquence de renouvellement de l'information de la mesure de la densité d'occupation spatiale DE(t), disponible à la sortie du multiplexeur 45. En fait, la sortie du multiplexeur 45 délivre au rythme des signaux issus du circuit d'horloge 35, les résultats des différentes sommation effectuées pendant des intervalles de temps T0, des longueurs des véhicules rentrant sur le tronçon 11. La valeur de la densité spatiale d'occupation DE(t) est déterminée par un circuit 70 recevant d'une part, la longueur L du tronçon 11 issue d'un circuit mémoire 39, et d'autre part, les signaux issus du multiplexeur 45. Le calcul de la pénibilité P(t) se fait alors de la même façon que pour le dispositif décrit à la figure 1. Son utilisation pour la commande d'un système de signalisation, par exemple du type optique, peut se faire soit par l'intermédiaire d'un comparateur 47 comme décrit précédemment, soit par l'intermédiaire d'un circuit de calcul 48 transformant la fonction du temps (t) de la pénibilité P(t) en une fonction F(t), cette fonction F étant choisie de façon à obtenir une variation quasi-linéaire de la fonction de pénibilité P(t) lorsque les conditions de trafic sur le tronçon 11 varient.A cyclic summation is thus obtained during time intervals of constant lengths equal to T 0 , offset from one another by a constant time interval T 1 , depending on the number N of summing circuits 41 which are available between l set of controlled switches 40 and the multiplexer 45. This number N thus determines the frequency of renewal of the information of the measurement of the spatial occupation density DE (t), available at the output of the multiplexer 45. In fact, the output of the multiplexer 45 delivers at the rate of the signals from the clock circuit 35, the results of the different summations carried out during time intervals T 0 , of the lengths of the vehicles entering the section 11. The value of the spatial density of occupation DE (t) is determined by a circuit 70 receiving on the one hand, the length L of the section 11 coming from a memory circuit 39, and on the other hand, the signals coming from the multiplexer 45. The calculation of the arduousness P (t) is then done in the same way so that for the device described in FIG. 1. Its use for controlling a signaling system, for example of the optical type, can be done either by means of a comparator 47 as described above, or by the intermediate of a computing circuit 48 transforming the fo nction of the time (t) of the arduous P (t) into a function F (t), this function F being chosen so as to obtain a quasi-linear variation of the arduous function P (t) when the traffic conditions on the section 11 vary.

Des expérimentations ont montré que de façon préférentielle, cette fonction F est une fonction logarithmique. Mais une fonction . P(T) peut également être utilisée. Ceci conduit donc à choisir le circuit de calcul 48 de façon à ce que les signaux disponibles sur sa borne de sortie 50, correspondent aux signaux définis par F(t) = /3 log (1 + (t)), où f3 est une constante prédéterminée. Les signaux issus de ce circuit 48 peuvent alors, soit directement commander le système de signalisation optique, soit commander ce même système de signalisation optique mais par l'intermédiaire d'un comparateur non représenté ici et similaire au comparateur 47 décrit précédemment.Experiments have shown that, preferentially, this function F is a logarithmic function. But a function. P (T) can also be used. This therefore leads to choosing the calculation circuit 48 so that the signals available on its output terminal 50 correspond to the signals defined by F (t) = / 3 log (1 + (t)), where f3 is a predetermined constant. The signals from this circuit 48 can then either directly control the optical signaling system, or control this same optical signaling system but via a comparator not shown here and similar to the comparator 47 described above.

On peut évidemment concevoir une réalisation différente du circuit 60 calculant à partir des circuits de mesure locale 1 et 3, d'une part la valeur de la densité d'occupation spatiale DE(t), et d'autre part la vitesse moyenne VM des véhicules sur le tronçon routier 11.It is obviously possible to conceive a different embodiment of the circuit 60 calculating from the local measurement circuits 1 and 3, on the one hand the value of the spatial occupation density DE (t), and on the other hand the average speed VM of the vehicles on the stretch road 11.

Dans l'exemple de réalisation du dispositif selon l'invention montrée à la figure 1, le circuit 12 de détermination de la densité d'occupation spatiale, plus particulièrement dans le cas où il comporte un circuit de calcul du type microprocesseur avec ses circuits périphériques, peut directement délivrer un signal de commande au système de signalisation, par exemple du type optique, dans le cas où l'un des véhicules représenté par la succession d'un ensemble d'impulsions binaires unité, correspond à une longueur supérieure et/ou égale à une valeur prédéterminée stockée en permanence dans une mémoire comprise dans le circuit 12 de détermination de la densité d'occupation spatiale. Ceci peut être particulièrement intéressant dans le cas d'un tronçon routier sur lequel de nombreux véhicules lourds par exemple du type autobus ou camions sont amenés à passer.In the embodiment of the device according to the invention shown in FIG. 1, the circuit 12 for determining the density of spatial occupancy, more particularly in the case where it includes a microprocessor type calculation circuit with its peripheral circuits , can directly deliver a control signal to the signaling system, for example of the optical type, in the case where one of the vehicles represented by the succession of a set of unit binary pulses, corresponds to a greater length and / or equal to a predetermined value permanently stored in a memory included in the circuit 12 for determining the density of spatial occupancy. This can be particularly advantageous in the case of a road section over which many heavy vehicles, for example of the bus or truck type are required to pass.

La commande du système de signalisation par exemple du type optique, commandée par la mesure de la fonction du pénibilité de ce tronçon routier peut alors être doublement commandée, d'une part par la valeur de cette fonction de pénibilité, d'autre part par le signal issu du circuit 12 de détermination de la densité d'occupation spatiale généré à l'arrivée d'un véhicule lourd ou de longueur importante.The control of the signaling system, for example of the optical type, controlled by measuring the arduousness function of this road section can then be doubly controlled, on the one hand by the value of this arduousness function, on the other hand by the signal from circuit 12 for determining the density of spatial occupancy generated at the arrival of a heavy vehicle or of considerable length.

On a ainsi décrit un dispositif de mesure de trafic routier et un système de signalisation, plus particulièrement du type optique, comportant un tel dispositif.A device for measuring road traffic and a signaling system, more particularly of the optical type, comprising such a device have thus been described.

Claims (9)

1. Dispositif de mesure du trafic routier sur un tronçon (11) de longueur (L), caractérisé en ce qu'il comporte un premier circuit de calcul (60) délivrant d'une part, un signal DE(t) correspondant à la densité d'occupation spatiale de ce tronçon (11) en fonction du temps, égale au quotient de la somme des longueurs (Li) des différents véhicules se trouvant sur ce tronçon (11), par la longueur L de ce tronçon (11) et d'autre part, un signal VM correspondant à la vitesse moyenne des véhicules sur ce tronçon (11) calculée sur un temps T prédéterminé, un second circuit de calcul (20) délivrant le signal (P(t)) = αDE(t)/VM, où α est une constante prédéterminée, commandant au moins les signaux situés sur et/ou à proximité de ce tronçon (11).1. A device for measuring road traffic over a section (11) of length (L), characterized in that it comprises a first calculation circuit (60) delivering on the one hand, a signal DE (t) corresponding to the density of spatial occupancy of this section (11) as a function of time, equal to the quotient of the sum of the lengths (Li) of the different vehicles on this section (11), by the length L of this section (11) and on the other hand, a signal VM corresponding to the average speed of the vehicles on this section (11) calculated over a predetermined time T, a second calculation circuit (20) delivering the signal (P (t)) = αDE (t) / VM, where α is a predetermined constant, controlling at least the signals located on and / or near this section (11). 2. Dispositif de mesure du trafic routier selon la revendication 1, caractérisé en ce que le premier circuit de calcul (60) comporte au moins un circuit (1) de mesure locale disposé à l'entrée du tronçon (11) de longueur L et déterminant la vitesse Vei et la longueur Li des véhicules passant par ce point.2. A device for measuring road traffic according to claim 1, characterized in that the first calculation circuit (60) comprises at least one local measurement circuit (1) disposed at the entrance to the section (11) of length L and determining the speed Vei and the length Li of the vehicles passing through this point. 3. Dispositif de mesure du trafic routier selon la revendication 2, caractérisé en ce que le premier circuit de calcul (60) comporte deux circuits (1 et 3) de mesure locale disposés l'un à l'entrée, l'autre à la sortie du tronçon (11), le premier circuit (1) déterminant la vitesse Vei et la longueur des véhicules Li, le second circuit (3) la vitesse Vsi de sortie des véhicules de ce tronçon (11).3. A device for measuring road traffic according to claim 2, characterized in that the first calculation circuit (60) comprises two local measurement circuits (1 and 3) arranged one at the entrance, the other at the leaving the section (11), the first circuit (1) determining the speed Vei and the length of the vehicles Li, the second circuit (3) the speed Vsi leaving the vehicles of this section (11). 4. Dispositif de mesure du trafic routier selon la revendication 1, caractérisé en ce qu'il comporte un circuit (48) connecté à la sortie du second circuit de calcul (20) et délivrant un signal P'(t) = F(t), la fonction F étant choisie de façon à ce que P' varie selon une courbe la plus proche possible d'une droite en fonction des différentes conditions de trafic sur le tronçon (11).4. A device for measuring road traffic according to claim 1, characterized in that it comprises a circuit (48) connected to the output of the second calculation circuit (20) and delivering a signal P '(t) = F (t ), the function F being chosen so that P 'varies according to a curve as close as possible to a straight line as a function of the different traffic conditions on the section (11). 5. Dispositif de mesure du trafic routier selon la revendication 4, caractérisé en ce que P' + β log (1+ P), ou encore P' = β√P où β est une constante prédéterminée.5. A device for measuring road traffic according to claim 4, characterized in that P '+ β log (1+ P), or also P' = β√P where β is a predetermined constant. 6. Dispositif de mesure du trafic routier selon la revendication 1, caractérisé en ce qu'il comporte, connecté à la sortie du second circuit de calcul (20), un comparateur (47) délivrant un signal si P(t) est supérieur ou égal à P0 et/ou P(t) est inférieur ou égal à P'0, Po et P'0 étant des nombres prédéterminés stockés dans un circuit mémoire (62) connecté au comparateur (47).6. A device for measuring road traffic according to claim 1, characterized in that it comprises, connected to the output of the second calculation circuit (20), a comparator (47) delivering a signal if P (t) is greater than or equal to P 0 and / or P (t) is less or equal to P ' 0 , P o and P' 0 being predetermined numbers stored in a memory circuit (62) connected to the comparator (47). 7. Dispositif de mesure du trafic routier selon la revendication 1, caractérisé en ce que le circuit (60) de détermination de la densité d'occupation spatiale DE(t) délivre le signal DE(t) défini par
Figure imgb0002
 Li, où la sommation s'effectue sur les longueurs Li mesurées des véhicules consécutifs occupant simultanément la longueur L du tronçon (11).7. A device for measuring road traffic according to claim 1, characterized in that the circuit (60) for determining the density of spatial occupation DE (t) delivers the signal DE (t) defined by
Figure imgb0002
 Li, where the summation takes place over the measured lengths Li of consecutive vehicles simultaneously occupying the length L of the section (11). 8. Dispositif de mesure du trafic routier selon les revendications 1 et 3, caractérisé en ce que le circuit de détermination (60) de la densité d'occupation spatiale DE(t) comporte au moins trois circuits mémoires du type registre à décalage (5, 6, 7) montés en série, le premier d'entre-eux (5) étant commandé par un signal d'horloge dont la fréquence est directement proportionnelle à la mesure de la vitesse moyenne des véhicules à l'entrée du tronçon (11), le second (6) par un signal d'horloge dont la fréquence est directement proportionnelle à la demi-somme des valeurs des vitesses moyennes d'entrée et de sortie des véhicules du tronçon (11), le troisième (7) par un signal d'horloge dont la fréquence est directement proportionnelle à la valeur de la vitesse moyenne de sortie des véhicules du tronçon (11).8. A device for measuring road traffic according to claims 1 and 3, characterized in that the circuit for determining (60) the spatial occupancy density DE (t) comprises at least three memory circuits of the shift register type (5 , 6, 7) connected in series, the first of them (5) being controlled by a clock signal whose frequency is directly proportional to the measurement of the average speed of the vehicles at the entrance to the section (11 ), the second (6) by a clock signal whose frequency is directly proportional to the half-sum of the values of the average speeds of entry and exit of the vehicles of the section (11), the third (7) by a clock signal whose frequency is directly proportional to the value of the average speed of exit of the vehicles of the section (11). 9. Système de signalisation routière, caractérisé en ce qu'il comporte un dispositif de mesure du trafic routier selon l'une quelconque des revendications précédentes.9. Road signaling system, characterized in that it comprises a device for measuring road traffic according to any one of the preceding claims.
EP80401243A 1979-09-07 1980-08-29 Measuring device for a road traffic parameter and signalling system comprising such a device Expired EP0025388B1 (en)

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FR7922451A FR2465283A1 (en) 1979-09-07 1979-09-07 DEVICE FOR MEASURING ROAD TRAFFIC, AND SIGNALING SYSTEM COMPRISING SUCH A DEVICE
FR7922451 1979-09-07

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CN105702060A (en) * 2016-03-04 2016-06-22 重庆交通大学 City signal intersection safety guiding method and system based on holographic projection technology

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