Traffic control systems and processes at a signalized intersection

Abstract

According to one aspect, the present description relates to a safety module (130) for a traffic control system (100) at an intersection (10). The traffic control system includes an intersection controller (110) configured to transmit electrical signals to optical units (21A, 22A, 23A) of the intersection lights, the electrical signals resulting from control signals. The safety module includes a receiver (135) configured to receive, via a wireless link, a message transmitted by a transmitter (120), the message being transmitted to connected vehicles to inform them of a presumed state of at least one optical unit; a measuring unit configured to determine, simultaneously with the reception of said message, an actual state of said at least one optical unit; and a processing unit configured to generate an inconsistency signal in case of a difference between the presumed state and the actual state of said at least one optical unit. Fig. 2

Description

Title of the invention: Systems and methods for controlling road traffic at a signalized intersection technical field

[0001] The invention relates to systems and methods for controlling road traffic in a signal intersection and applies in particular to traffic control in the presence of connected vehicles. State of the art

[0002] Connected vehicles, particularly driverless autonomous vehicles, need to know the status of traffic lights to determine whether they can proceed through a signalized intersection. This information is transmitted in a known manner by signalized intersection controllers via a secure wireless link. This link notably uses V2I (Vehicle-to-Infrastructure) standardized communication technology. The V2I wireless link may include, for example, Dedicated Short Range Communication (DSRC), which is part of the IEEE 802.11 WLAN family of standards and is known in the United States as Wireless Access in Vehicular Environments (WAVE) and in Europe as ITS-G5.Wireless V2I links can also be based on mobile phone networks, such as "cellular V2X", also known as C-V2X.

[0003] Regardless of the wireless communication technique used, care is taken to ensure that the information transmitted to the connected vehicles is not erroneous.

[0004] US patent published 11,521,486 [Ref. 1] describes in general terms traffic control systems and methods. [Fig. 1] reproduces by way of example a diagram of a traffic control system as described in [Ref. 1].

[0005] In such a traffic control system, a traffic controller 84, also called an intersection controller, is connected to a data aggregator 82, for example by an electrical connection 87 such as, for example, a copper wire, an aluminum wire, or an optical fiber. The intersection controller 84 is also connected to a roadside unit 70 (or "RSU") by means of an electrical connection 72, and the RSU 70 is connected to the data aggregator 82 by means of an electrical connection 74, for example, a metallic connection or an optical connection. The RSU 70 has an antenna 60 configured to transmit a signal into the cloud 64 (or "cloud"). (according to the Anglo-Saxon term) to a receiving antenna 66 which is connected to the data aggregator 82. Here, the "cloud" 64 can include a system configured to communicate with a central control facility, automobiles, buses, drones, other traffic light controllers, other data aggregators, etc. In operation, the intersection controller 84 transmits a dedicated Global Positioning System (GPS) signal for Digital Signal Crossing Response (DSRC) to the RSU 70, which in turn transmits a signal to the cloud 64, which transmits a signal to the receiver 66, which receiver 66 transmits the signal to the data aggregator 82. The RSU 70 also transmits the signal to the aggregator 82 in a wired feedback configuration via the electrical interconnect 74. The data aggregator 82 compares the wired feedback signal 74 with the wireless signal transmitted from the RSU 70 to the cloud.If there is a discrepancy between the wired signal 74 received by the data aggregator 82 and the wireless signal received by the data aggregator 82, the data aggregator 82 generates a comparison signal indicating the discrepancy or error. The comparison signal can serve as a fault indicator signal or an error signal and can be transmitted to the intersection controller 84 to indicate that an error detection or event mismatch has occurred. The intersection controller 84 can then transmit a signal to the cloud 64 indicating that the intersection should be placed in "flash mode," where all traffic lights display a flashing signal to ensure intersection safety. Such a traffic control system is particularly advantageous in the event of malicious signal spoofing.

[0006] One objective of the present description is to propose a road traffic control system that further improves the safety of the intersection, in particular an intersection in which connected vehicles circulate. Summary of the invention

[0007] In this description, the term "include" has the same meaning as "include" or "contain," and is inclusive or open-ended and does not exclude other elements not described or depicted. Furthermore, in this description, the term "approximately" or "substantially" is synonymous with (means the same as) a lower and / or upper margin of 10%, for example, 5%, of the respective value.

[0008] According to a first aspect, the present description relates to a safety module for a road traffic control system for an intersection comprising a set of traffic lights. The road traffic control system includes, in a known manner, an intersection controller for controlling the traffic lights of said first intersection, each traffic light comprising a plurality of optical units, each configured to emit a different colored optical signal, the intersection controller being configured to transmit electrical signals to said optical units by means of electrical lines. command for the control of optical signals, said electrical signals resulting from control signals.

[0009] The security module according to the first aspect comprises: - a receiver configured to receive, via wireless link, a message transmitted by a transmitter, said message being transmitted by said transmitter, via wireless link, to one or more connected vehicles moving in the intersection, and being configured to inform said connected vehicle(s) of a supposed state of at least one optical unit of at least one light, the supposed state being determined by said control signals; - a unit of measurement configured to determine simultaneously upon receipt of said message, by means of a measurement of a current signal and / or a voltage signal on the electrical control line of said at least one optical unit, a real state of said at least one optical unit; - a processing unit configured to generate an inconsistency signal in case of a difference between the assumed state and the actual state of said at least one optical unit.

[0010] Thus, in a safety module according to the first aspect, the receiver receives a message identical to that received by the connected vehicle(s). The message is configured to indicate a presumed state of at least one optical unit of at least one traffic light. To this end, the message is determined based on the control signals that generate the electrical signals transmitted to said at least one optical unit for controlling the optical signals. Furthermore, the measuring unit is configured to determine, simultaneously with the reception of said message, an actual state of said at least one optical unit. Simultaneous determination means that the latency between the measurement of the actual state of said at least one optical unit and the reception of the message indicating the presumed state is less than 500 ms, advantageously less than 300 ms, and advantageously less than 100 ms.

[0011] In practice, in exemplary embodiments, the control signals are defined according to a timing that determines the times at which the electrical signals are transmitted to the optical units and the transmission times of these signals as a function of the desired duration of the corresponding optical signal emission. Messages are transmitted to the connected vehicles and to the receiver of the safety module, in exemplary embodiments, with a predetermined periodicity. For example, the messages are transmitted at time intervals between approximately 100 ms and approximately 500 ms. In exemplary embodiments, the latency between the measurement of the actual state of said at least one optical unit and the reception of the message informing of the assumed state is less than the time interval between the transmission of two messages.

[0012] The applicant has shown that the safety module according to the first aspect makes it possible to ensure that the state information of one or more traffic lights transmitted to the connected vehicles, i.e., the optical signal emitted by the optical unit(s) of said traffic light(s) (e.g., "red light," "green light"), is rigorously identical to the visual information delivered by said traffic light(s). Thus, the safety module according to the first aspect makes it possible, as in the prior art described in [Ref. 1], to ensure the integrity of a transmitted message, but also to identify any inconsistency between the information from said traffic light(s) transmitted to the connected vehicles and the visual information corresponding to the actual state of said traffic light(s). An inconsistency can occur, in particular, in the event of excessive latency (e.g.greater than approximately 500 ms) between the transmission of information to connected vehicles about the status of the lights and the transmission of electrical signals to control the status of the lights.

[0013] In exemplary embodiments, said message is configured to inform said connected vehicle(s) of a supposed state of each optical unit of a plurality of optical units of at least one traffic light. The measuring unit is then configured to simultaneously determine, by means of a measurement of a current signal and / or a voltage signal on the electrical control line of each optical unit of said plurality of optical units, an actual state of each optical unit, and the processing unit is configured to generate said inconsistency signal in the event of a difference between the supposed state and the actual state of at least one optical unit of said plurality of optical units.

[0014] The message is for example a SPaT message (acronym for the Anglo-Saxon abbreviation "Signal Phase and Timing") as defined by the ETSI TS 103 301, ISO / TS 19091 and SAE J2735 standards.

[0015] According to one or more embodiments, the processing unit of the safety module is configured to transmit the inconsistency signal to the intersection controller in order to switch the intersection to a safe state and / or to stop the transmission of messages by the transmitter. A "safe state" of the intersection is, for example, a state in which the lights are flashing yellow or a state in which the lights are off. By stopping the transmission of messages by the transmitter, the connected vehicles enter a so-called "degraded mode" in which they no longer receive status information from the optical units.

[0016] According to one or more embodiments, the receiver of the security module includes an electronic communication card for wireless link connected to an antenna.

[0017] According to one or more embodiments, the safety module is external to the intersection controller, that is to say that the entire receiver, measuring unit and processing unit are arranged in a case external to a case in which the intersection controller is arranged.

[0018] According to one or more embodiments, the safety module is integrated, or at least partially integrated, into the intersection controller, that is to say that all or part of the components forming the safety module are arranged in the housing in which the intersection controller is arranged.

[0019] For example, in embodiment examples, the unit of measurement configured to determine a real state of the optical unit(s) is a component of the intersection controller.

[0020] According to a second aspect, the present description relates to a road traffic control system for at least a first intersection comprising a set of lights, the control system comprising at least a first safety module according to the first aspect.

[0021] According to one or more exemplary embodiments, the road traffic control system according to the second aspect comprises: - at least one first intersection controller for the control of the lights of said first intersection, each light comprising a plurality of optical units each configured to emit an optical signal of a different color, the first intersection controller being configured to transmit electrical signals to said optical units by means of electrical control lines for the control of the optical signals, said electrical signals resulting from control signals; - a transmitter configured to transmit to one or more connected vehicles moving in the first intersection, via wireless link, initial messages with a given periodicity, each initial message being configured to inform said connected vehicle(s) of a supposed state of at least one optical unit of at least one light, the supposed state being determined by said control signals; - at least one first safety module according to the first aspect, configured to generate an inconsistency signal in case of difference between the supposed state and the actual state of said at least one optical unit.

[0022] In a road traffic control system according to the second aspect, the transmitter is, for example, an electronic communication card for wireless communication connected to an antenna. The first message transmitted by the transmitter via wireless communication is, for example, an SPaT message indicating the presumed state of said at least one optical unit.

[0023] In exemplary embodiments, said first messages are transmitted at time intervals of between approximately 100 ms and approximately 500 ms.

[0024] According to one or more embodiments, the first junction controller is configured to transmit to said transmitter, via a wired connection, said first control signals for determining the assumed state of said at least one optical unit. The wired connections are, for example, electrical or optical connections.

[0025] In exemplary embodiments, the transmitter may comprise an electronic board integrated into the intersection controller, i.e., arranged in the same housing as the intersection controller, said housing being arranged near said first intersection. The transmitter may share a common power supply with the intersection controller.

[0026] In other embodiments, the transmitter may be an external component of the intersection controller, dedicated to wireless communication with connected vehicles. In these examples, the transmitter is located outside the intersection controller housing. For example, it is mounted on the intersection itself.

[0027] According to one or more exemplary embodiments, the first intersection controller is configured to generate at least a part of said first control signals.

[0028] Thus, in exemplary embodiments, all the initial control signals are generated by the first junction controller. For example, the control signals are generated according to a pre-established timing schedule defining the sequence of the control signals. The sequence of the control signals defines the times at which the electrical signals are transmitted to the optical units and their durations.

[0029] According to one or more embodiments, the road traffic control system further comprises a centralized traffic management unit, and at least some of the initial control signals are generated by this centralized traffic management unit. As before, the control signals can be generated according to a pre-established timing schedule defining the sequence and duration of the control signals.

[0030] The aforementioned first control signals generated by the centralized traffic management unit are then transmitted via wired connection to the first junction controller for the control of the optical signals of the optical units. In some embodiments, the wired connections are made using electrical or optical connections.

[0031] In exemplary embodiments, only some of the initial control signals are generated by the centralized traffic management unit, and the first intersection controller is configured to generate the remaining initial control signals based on the initial control signals received by the centralized traffic management unit. For example, the centralized traffic management unit is configured to transmit to the intersection controller the control signal to activate the green optical unit of the traffic light. The control signals for the other optical units can then be generated by the intersection controller.

[0032] In some embodiments, the first set of control signals is generated by the centralized traffic management unit and transmitted by wired link to the first intersection controller.

[0033] In exemplary embodiments, said centralized traffic management unit is configured to transmit said transmitter, via wired link, said first control signals for determining the supposed state of said at least one optical unit.

[0034] According to one or more embodiments, the first safety module is configured to transmit said inconsistency signal to said first intersection controller and said first intersection controller is configured to transmit said inconsistency signal to said centralized traffic management unit, said centralized traffic management unit being configured to in turn transmit an alert signal to the first intersection controller in order to switch the intersection to a safe state and / or to stop the transmission of messages by the sender.

[0035] In exemplary embodiments, the centralized traffic management unit is configured to generate second control signals which are transmitted by wired link to a second junction controller of a second junction.

[0036] According to one or more embodiments, the transmitter is configured to also transmit, via wireless link, second messages at a given interval, each second message being configured to inform one or more connected vehicles of a presumed state of at least one optical unit of at least one traffic light at the second intersection, the presumed state being determined by said second control signals. In some embodiments, said transmitter receives control signals from the centralized traffic management unit for the transmission of each first and second message. In some embodiments, the first and second messages each incorporate geolocation data for the traffic lights, i.e., they contain information relating to their GPS position.

[0037] In exemplary embodiments, the road traffic control system includes said second intersection controller for the control of lights of said second intersection and a second safety module configured to receive every second message by wireless link, simultaneously determine, by means of a measurement of a current signal and / or a voltage signal on the electrical control line of at least one optical unit of a light of the second intersection, an actual state of said at least one optical unit and generate an inconsistency signal in case of difference between the assumed state and the actual state of said at least one optical unit.

[0038] According to one or more embodiments, the centralized traffic management unit is configured to generate said first control signals and transmit them via wired link to the first junction controller, and is configured to generate second control signals and transmit them via wired link to the second junction controller of the second junction; the transmitter receives the first signals command and second command signals from the centralized traffic management unit for the transmission of first and second messages.

[0039] According to one or more embodiments, the first intersection controller is configured to generate said first control signals, and the second intersection controller at the second intersection is configured to generate second control signals. The centralized traffic management unit is configured to receive, via a wired connection, said first control signals generated by the first intersection controller and is configured to receive, via a wired connection, said second control signals generated by the second intersection controller. The transmitter then receives the first and second control signals from the centralized intersection management unit for the transmission of the first and second messages.

[0040] According to a third aspect, the present description relates to a method of controlling road traffic at at least a first intersection, implemented by a road traffic control system according to the second aspect.

[0041] More specifically, said first intersection comprising a set of traffic lights, each traffic light comprising a plurality of optical units each configured to emit an optical signal of a different color, the method comprises: - the transmission, by a first intersection controller, of electrical signals to said optical units by means of electrical control lines for the control of optical signals, said electrical signals resulting from control signals; - the transmission to one or more connected vehicles moving in the first intersection, by wireless link, by means of a transmitter, of first messages with a given periodicity, each first message being configured to inform said connected vehicle(s) of a supposed state of at least one optical unit of at least one light, the supposed state being determined by said control signals; - the reception of each first message by a first security module; - simultaneously with said reception of said first message, the determination, by said first security module and by means of a measurement of a current signal and / or a voltage signal on the electrical control line of said at least one optical unit, of a real state of said at least one optical unit; - the generation, by said first security module, of an incoherence signal in case of difference between the supposed state and the actual state of at least one optical unit. Brief description of the figures

[0042] Other features and advantages of the invention will become apparent from the following description, illustrated by the following figures:

[0043] Fig. 1 (already described) represents a diagram of a known state-of-the-art traffic control system;

[0044] Fig. 2 is a diagram illustrating a first example of a road traffic control system according to the present description;

[0045] Fig. 3 is a diagram illustrating a second example of a road traffic control system according to the present description;

[0046] Fig. 4 is a diagram illustrating in more detail elements of an example of a road traffic control system according to the present description;

[0047] Fig. 5 is a diagram illustrating in more detail an example of measuring the actual state of an optical unit by means of a safety module according to the present description;

[0048] Fig. A is a diagram illustrating a third example of a road traffic control system according to the present description;

[0049] Fig. B is a diagram illustrating a fourth example of a road traffic control system according to the present description. Detailed description

[0050] In the figures, the elements are not shown to scale for better visibility.

[0051] Fig. 2 is a diagram illustrating a first example of a road traffic control system according to the present description.

[0052] In the example of [Fig. 2], the system 100 is configured for the control of road traffic at an intersection 10 comprising a set of traffic lights. In [Fig. 2], four traffic lights 20a, 20b, 20c, 20d are shown, but of course, there may be fewer or more; moreover, the set of traffic lights may include lights for motor vehicles, bicycles, pedestrians, etc. Each traffic light comprises a plurality of optical units (21A, 22A, 23A), each configured to emit a different colored optical signal, for example, red, green, yellow. Thus, in [Fig. 2], light 20A comprises a plurality of three optical units 21A, 22A, 23A; light 20B comprises a plurality of three optical units 21B, 22B, 23B; light 20C comprises a plurality of three optical units 21c, 22c, 23c; and light 20D comprises a plurality of three optical units 21D, 22D, 23D. Of course, each light can comprise a greater or lesser number of optical units.

[0053] As illustrated in [Fig. 2], the road traffic control system 100 includes an intersection controller 110 for controlling the traffic lights at intersection 10. The intersection controller 110 is configured to transmit electrical signals to said optical units by means of control power lines referenced respectively 30a, 30b, 30c, 30d, for controlling the optical signals, said electrical signals resulting from control signals. For example, the control signals are generated by the junction controller 10. For example, the control signals are generated according to a pre-established timing schedule defining the sequence of the control signals. The sequence of the control signals defines the times at which the electrical signals are transmitted to the optical units and their durations, typically a few tens of seconds.

[0054] The road traffic control system 100 further includes a transmitter 120 configured to transmit to one or more connected vehicles 50 moving in the intersection 10, by wireless link, messages with a given periodicity, each message being configured to inform said connected vehicle(s) 50 of a supposed state of at least one optical unit of at least one light, the supposed state being determined by said control signals.

[0055] The message is, for example, a SPaT message (acronym for the Anglo-Saxon abbreviation "Signal Phase and Timing"). Each message may include information relating to a supposed state of one or more optical units of one or more lights.

[0056] Transmitter 120 is configured for wireless transmission, for example, short-range transmission (or DSRC, according to the Anglo-Saxon abbreviation "Dedicated Short Range Communication"), which is part of the IEEE 802.11 WLAN family of standards and is known in the United States as "Wireless Access in Vehicular Environments" (WAVE) and in Europe as ITS-G5. The V2I wireless link can also be based on the mobile telephone network, such as "cellular V2X," also known as C-V2X.

[0057] As illustrated in [Fig. 2], the transmitter may comprise an electronic board integrated into the intersection controller, i.e., arranged in the same housing as the intersection controller, said housing generally being located near said first intersection, i.e., at a distance of less than 100 meters. In some embodiments, the transmitter may share a common power supply with the intersection controller.

[0058] In this example, the intersection controller transmits the control signals to the transmitter via a wired connection. Wired connections are, for example, electrical or optical connections.

[0059] Generally, wired connections, for example electrical or optical connections, will be represented in solid lines in the figures, and wireless connections in dotted lines.

[0060] The road traffic control system 100 further includes a safety module 130 configured to generate an inconsistency signal in the event of a difference between the assumed state and an actual state of said at least one optical unit, as will be described in more detail later.

[0061] Figure 3 is a diagram illustrating a second example of a road traffic control system according to the present description. The road traffic control system 200 described in Figure 3 is substantially similar to the road traffic control system 100 described in Figure 2, and the elements are not detailed again.

[0062] Unlike the road traffic control system 100, in the example of the road traffic control system 200 described in [Fig. 3], the transmitter 120 is an external component of the intersection controller, dedicated to wireless communication with connected vehicles, for example, a roadside unit or RSU (Road Side Unit). The roadside unit is equipped with wireless communication technology, such as dedicated short-range communication (DSRC) or C-V2X communication. The roadside unit is located outside the housing that contains the intersection controller. It can, for example, be mounted on a support for traffic lights, road signs, or other intersection infrastructure.

[0063] As before, the junction controller 110 is configured to transmit the first control signals to the transmitter 120 via a wired connection. Wired connections are, for example, electrical or optical connections.

[0064] Figure 4 is a diagram illustrating in more detail a 130 security module of a road traffic control system according to this description and its operation with the intersection controller 110 and the transmitter 120.

[0065] In the example illustrated in [Fig. 4], only two traffic lights 20A, 20B are shown. The intersection controller 110 includes, for example, a power relay 112 connected to a power supply 105. The intersection controller 110 also includes, in this example, a processor 116 or CPU (Central Processing Unit), in which the control signals are programmed according to a pre-established time schedule, and a switching board 114 configured to supply the control power lines 30A, 30B respectively to the optical units of the traffic lights 20A, 20B according to the control signals received from the processor 116. Thus, for example, in the example illustrated in [Fig. 4], each power line 30A, 30B includes a plurality of connecting wires, for example, 4 connecting wires in this example, to supply each optical unit of a traffic light. In the example of [Fig.[4] We have thus illustrated the connecting wires 31A, 32A, 33A, 34A to connect respectively the optical units 21A, 22A, 23A ([Fig.2]), the last connecting wire 34A being the common potential. .

[0066] In exemplary embodiments, the switching card 114 of the controller 110 can send the processor 116 a real state of the optical units. In case of inconsistency between the real state of an optical unit and the assumed state corresponding to the signal of The processor 116 can transmit a signal to the power relay 112, for example, to cut off the power supply and turn off the lights at the intersection.

[0067] The security module 130 includes a receiver 135 configured to receive, via wireless link, the message transmitted by the transmitter 120. The receiver includes, for example, an electronic communication card for wireless link connected to an antenna.

[0068] The security module also includes a measuring unit 133 and a processing unit 137.

[0069] The measuring unit 133, an example of which is described in more detail in [Fig.5], is configured to determine simultaneously upon receipt of the message, a real state of the optical unit(s), by means of a measurement of a current signal and / or a voltage signal on the electrical control line of said at least one optical unit.

[0070] The processing unit 137 is configured to generate an inconsistency signal in case of a difference between the assumed state and the actual state of said at least one optical unit.

[0071] For example, as illustrated in [Fig. 4], the processing unit 137 is configured to transmit the inconsistency signal to the intersection controller 110 in order to switch the intersection to a safe state. A "safe state" of the intersection is, for example, a state in which the lights are flashing yellow or a state in which the lights are off. More specifically, in embodiments such as those illustrated in [Fig. 4], the inconsistency signal can be transmitted directly to the power relay 112 to cut off the power supply and turn off the intersection lights.

[0072] In other embodiments, the processing unit 137 can be configured to transmit the said inconsistency signal to the junction controller 110 in order to stop the transmission of messages by the transmitter 120. The inconsistency signal can then be transmitted to the processor 116.

[0073] Thus, in a safety module according to the first aspect, the receiver receives a message identical to that received by the connected vehicle(s). The message is configured to indicate a supposed state of at least one optical unit of at least one light. To this end, the message is determined based on the control signals that generate the electrical signals transmitted to said at least one optical unit for controlling the optical signals. Furthermore, the measuring unit is configured to determine, simultaneously with the reception of said message, an actual state of said at least one optical unit. By simultaneous, it is understood that the latency between the measurement of the actual state of said at least one optical unit and the reception of the message indicating the supposed state is less than 500 ms, advantageously less than 300 ms, advantageously less than 100 ms. Advantageously, in examples of In this implementation, the latency between measuring the actual state of at least one optical unit and receiving the message indicating the assumed state is less than the time interval between the transmission of two messages. Messages can indeed be transmitted to the connected vehicles and the receiver of the safety module, in some embodiments, with a predetermined periodicity. For example, messages are transmitted at time intervals ranging from approximately 100 ms to approximately 500 ms.

[0074] The applicant has shown that the safety module according to the first aspect makes it possible to ensure that the status information of one or more lights transmitted to the connected vehicles, i.e. the optical signal emitted by the optical unit(s) of said light(s) (e.g. "red light", "green light"), is rigorously identical to the visual information delivered by said light(s).

[0075] Indeed, the safety module makes it possible to identify any inconsistency between the information from the traffic lights transmitted to the connected vehicles and the visual information corresponding to the actual state of the traffic lights. An inconsistency can occur, in particular, in the event of excessive latency (e.g., greater than approximately 500 ms) between the transmission of information to the connected vehicles about the state of the traffic lights and the transmission of the electrical signals to control the state of the traffic lights. An inconsistency can also occur in the event of an intrusion into wireless communications (e.g., a cyberattack). In the case of using a roadside unit for sending messages ([Fig. 3]), an inconsistency can also occur in the event of signal degradation between the intersection controller 110 and the roadside unit 120 or in the event of an intrusion.

[0076] Fig. 5 is a diagram illustrating in more detail an example of measuring the actual state of an optical unit by means of a safety module according to the present description.

[0077] As illustrated in [Fig. 5], the measuring unit 133 in this example is configured to measure, on the one hand, the current intensity on each connecting wire 31A, 32A, 33a for the electrical connection of the optical units 21A, 22A, 23A of the 20A light. This measurement is symbolized by the ammeter A. The measuring unit 133 in this example is also configured to measure the voltage between each connecting wire 31A, 32A, 33a and the common potential (connecting wire 34A). This measurement is symbolized by the voltmeter V. A combination of the current and voltage measurements makes it possible to accurately determine the actual state of the 20A optical unit. Of course, this measurement method is not exhaustive.

[0078] Note that in the examples illustrated in the figures, the safety module 130 is shown as being external to the intersection controller 110, that is to say that The receiver, measuring unit and processing unit are arranged in a separate housing outside the housing containing the intersection controller.

[0079] However, other embodiments are possible. In particular, the safety module 130 can be integrated, or at least partially integrated, into the intersection controller 110, i.e., all or part of the components forming the safety module are arranged in the housing in which the intersection controller is housed. For example, the measuring unit 133 can be a measuring unit already included in the intersection controller.

[0080] Figure 1A is a diagram illustrating a third example of a road traffic control system 300 according to this description, configured to control road traffic at a first intersection 10A and at least a second intersection (not shown). The first intersection 10A is, for example, similar to intersection 10 in Figure 2. It is controlled by an intersection controller 110A. A safety module 130A, as described previously, generates an inconsistency signal in the event of a difference between the assumed state of at least one optical unit transmitted to a connected vehicle 50A moving through intersection 10A and the actual state of said at least one optical unit.

[0081] In the example illustrated in [Fig. A], the road traffic control system 300 further includes a centralized traffic management unit 150, at least part of the first control signals being generated by the centralized traffic management unit 150 and transmitted by wire link to said first intersection controller 110A.

[0082] As illustrated in [Fig. A], the centralized traffic management unit 150 is further configured to generate second control signals which are transmitted by wire link to a second junction controller 110B of the second junction.

[0083] In exemplary embodiments, only some of the first and second control signals are generated by the central traffic management unit 150. The first intersection controller 110A is configured to generate the remaining first control signals based on the first control signals received by the central traffic management unit 150, and the intersection controller 110B is configured to generate the remaining second control signals based on the second control signals received by the central traffic management unit 150. For example, the central traffic management unit is configured to transmit to the intersection controller the control signal to activate the green optical unit of the traffic light. The control signals for the other optical units can then be generated by the intersection controller.

[0084] In this example, transmitter 120 is configured to also transmit, via wireless link, second messages to connected vehicles moving in the second intersection. As illustrated in [Fig. 0A], transmitter 120 receives the first and second control signals from the central traffic management unit for the transmission of the first and second messages. In some embodiments, the first and second messages each incorporate geolocation data for the traffic lights, i.e., they contain information relating to their GPS position.Thus, connected vehicles moving in the first intersection 10A will only be able to take into account the messages relating to the traffic lights of the first intersection, and connected vehicles moving in the second intersection will only be able to take into account the messages relating to the traffic lights of the second intersection.

[0085] The transmitter 120 is advantageously a long-range wireless communication module. It is configured, for example, for transmitting messages using long-range cellular technology, such as 4G or 5G.

[0086] As before, the 130A safety module identifies any inconsistency between the information from the traffic lights transmitted to the connected vehicles and the visual information corresponding to the actual state of the traffic lights. An inconsistency can occur, in particular, in the event of latency between the transmission of information on the state of the traffic lights to the connected vehicles via transmitter 120 and the transmission of the electrical signals to control the state of the traffic lights. An inconsistency can also occur in the event of an intrusion into wireless communications (e.g., a cyberattack) or in the event of signal degradation or intrusion between the transmitter of the centralized traffic management unit 120 and the intersection controller no. A.

[0087] Fig. B is a diagram illustrating a fourth example of a road traffic control system 400 according to this description, configured to control road traffic from a first junction 10A and at least a second junction (not shown).

[0088] The road traffic control system 400 is substantially similar to the road traffic control system 300 illustrated in [Fig. 0A].

[0089] In this example, however, the first junction controller 110A is configured to generate the first control signals, and the second junction controller 110B of the second junction (not shown) is configured to generate the second control signals. The centralized traffic management unit 150 is configured to receive, via wired connection, the first control signals generated by the The first intersection controller and the second control signals are generated by the second intersection controller. Transmitter 120 then receives the first and second control signals from the centralized intersection management unit 150 for the transmission of the first and second messages.

[0090] As before, the safety module 130A makes it possible to identify any inconsistency between the information from said traffic lights transmitted to the connected vehicles 50a moving in the first intersection and the visual information corresponding to the actual state of said traffic lights. An inconsistency can occur, in particular, in the event of latency between the transmission of information on the state of the traffic lights to the connected vehicles by means of the transmitter 120 and the transmission of the electrical signals to control the state of the traffic lights. An inconsistency can also occur in the event of an intrusion into wireless communications (e.g., cyberattack) or in the event of signal degradation or intrusion between the transmitter of the centralized traffic management unit 120 and the intersection controller 110A.

[0091] In the examples of [Fig. A] and [Fig. B], the first safety module 130A can be configured to transmit the inconsistency signal to the first intersection controller 110A if an inconsistency signal is generated, and the first intersection controller can be configured to transmit the inconsistency signal to the centralized traffic management unit 150, said centralized traffic management unit being configured to in turn transmit an alert signal to the first intersection controller, for example for switching the intersection to a safe state.

[0092] Although described through a number of embodiment examples, the safety module, the road traffic control system and method according to this description include various variants, modifications and improvements which will be obvious to a person skilled in the art, it being understood that these various variants, modifications and improvements are part of the scope of the invention as defined by the following claims. References

[0093] Ref. 1: US 2007 / 0195990

Claims

Demands

1. Safety module (130) for a road traffic control system (100) of an intersection (10) comprising a set of lights (20A, 20b, 20c, 20d), the road traffic control system comprising an intersection controller (110) for the control of the lights of said intersection, each light (20A) comprising a plurality of optical units (21A, 22A, 23A) each configured to emit an optical signal of a different color, the intersection controller being configured to transmit electrical signals to said optical units by means of electrical control lines (30A, 30B, 30c, 30d) for the control of the optical signals, said electrical signals resulting from control signals;the safety module comprising: - a receiver (135) configured to receive, via wireless link, a message transmitted by a transmitter (120), said message being transmitted by said transmitter (120), via wireless link, to one or more connected vehicles (50) moving in the first intersection, and being configured to inform said connected vehicle(s) (50) of a supposed state of at least one optical unit of at least one traffic light, the supposed state being determined by said control signals; - a measuring unit (133) configured to determine simultaneously upon receipt of said message, by means of a measurement of a current signal and / or a voltage signal on the electrical control line of said at least one optical unit, an actual state of said at least one optical unit; - a processing unit (137) configured to generate an inconsistency signal in case of a difference between the supposed state and the actual state of said at least one optical unit.

2. Safety module according to claim 1, wherein: - said message is configured to inform said connected vehicle(s) (50) of a supposed state of each optical unit of a plurality of optical units of at least one light, and - the measuring unit (133) is configured to simultaneously determine, by means of a measurement of a current signal and / or a voltage signal on the electrical control line of each optical unit of said plurality of optical units, an actual state of each optical unit; - the processing unit (137) is configured to generate said inconsistency signal in case of difference between the assumed state and the actual state of at least one optical unit of said plurality of optical units.

3. A safety module according to any one of the preceding claims, wherein the processing unit (137) is configured to transmit said intersection controller said inconsistency signal in order to switch the intersection into a safe state and / or to stop the transmission of messages by the sender.

4. A road traffic control system (100) for at least one first intersection (10) comprising a set of lights (20A, 20B, 20c, 20D), the system comprising: - at least one first intersection controller (110, 110A) for controlling the lights of said first intersection, each light (20A) comprising a plurality of optical units (21A, 22A, 23A) each configured to emit an optical signal of a different color, the first intersection controller being configured to transmit electrical signals to said optical units by means of control power lines (30A) for controlling the optical signals, said electrical signals resulting from control signals;- a transmitter (120) configured to transmit to one or more connected vehicles (50) moving in the first intersection, via wireless link, initial messages at a given periodicity, each initial message being configured to inform said connected vehicle(s) (50) of a supposed state of at least one optical unit of at least one traffic light, the supposed state being determined by said control signals; - at least one first safety module (130) according to any one of the preceding claims, configured to generate an inconsistency signal in the event of a difference between the supposed state and the actual state of said at least one optical unit.

5. System according to claim 4, wherein the first intersection controller (110) is configured to generate at least a portion of said first control signals.

6. A system according to any one of claims 4 or 5, wherein the first intersection controller (110) is configured to transmit said transmitter (120), via a wired connection, said first control signals for determining the supposed state of said at least one optical unit.

7. System according to any one of claims 4 to 6, further comprising a centralized traffic management unit (150) and wherein at least a portion of the first control signals are generated by the centralized traffic management unit (150) and transmitted by wire link to said first intersection controller.

8. System according to claim 7, wherein said centralized traffic management unit is configured to transmit said transmitter (120), via wired link, said first control signals for determining the supposed state of said at least one optical unit.

9. System according to any one of claims 7 or 8, wherein said first safety module (130) is configured to transmit said inconsistency signal to said first intersection controller and said first intersection controller is configured to transmit said inconsistency signal to said centralized traffic management unit (150), said centralized traffic management unit being configured to in turn transmit an alert signal to the first intersection controller in order to switch the intersection to a safe state and / or to stop the transmission of messages by the sender.

10. System according to any one of claims 7 to 9, wherein the centralized traffic management unit (150) is configured to generate second control signals which are transmitted via wired link to a second junction controller (110B) of a second junction.

11. System according to claim 10, wherein the transmitter (120) is configured to further transmit, via wireless link, second messages with a given periodicity, each second message being configured to inform one or more connected vehicles of a supposed state of at least one optical unit of at least one light of the second intersection, the supposed state being determined by said second control signals.

12. A method for controlling road traffic at at least one first intersection (10), said first intersection comprising a set of lights (20A, 20b, 20c, 20d), each light (20A) comprising a plurality of units optical elements (21A, 22A, 23A) each configured to emit an optical signal of a different color, the method comprising: - the transmission, by a first intersection controller (110, 110A), of electrical signals to said optical units by means of electrical control lines (30A, 30B, 30c, 30D) for the control of the optical signals, said electrical signals resulting from control signals; - the transmission to one or more connected vehicles (50) moving in the first intersection, by wireless link, by means of a transmitter (120), of the first messages with a given periodicity, each first message being configured to inform the said connected vehicle(s) (50) of a supposed state of at least one optical unit of at least one light, the supposed state being determined by said control signals; - the reception of each first message by a first security module (130); - simultaneously with said reception of said first message, the determination, by said first security module and by means of a measurement of a current signal and / or a voltage signal on the electrical control line of said at least one optical unit, of a real state of said at least one optical unit; - the generation, by said first safety module, of an incoherence signal in case of difference between the supposed state and the actual state of said at least one optical unit.

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