Traffic control system and operation switching method

Abstract

To suppress an occurrence frequency of a situation where traffic in a road network cannot be appropriately managed.SOLUTION: A first terminal corresponding apparatus and a second terminal corresponding apparatus are connected to a central apparatus by a first network, are connected to a router by a second network, and perform transmission and reception processing for transmitting and receiving data between the central apparatus and a traffic terminal. The first terminal corresponding apparatus performs the transmission and reception processing when a standby instruction is not notified from the second terminal corresponding apparatus, and stops the transmission and reception processing when the standby instruction is notified from the second terminal corresponding apparatus. The second terminal corresponding apparatus starts the transmission and reception processing when it is confirmed that the central apparatus is connected by the first network and it is not confirmed that connection with the first terminal corresponding apparatus is established by the first network.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technology for managing traffic on a road network by utilizing a plurality of traffic terminals (for example, signal control devices, guide boards, vehicle detectors, and vehicle number readers) installed on the road network. [Background technology]

[0002] Conventionally, there have been traffic control systems that manage traffic on road networks. As shown in Patent Document 1, for example, a traffic control system includes a central unit installed in a traffic control center and multiple traffic terminals installed on the road network. The traffic control system installs traffic terminals of different types at multiple points on the roads that make up the road network, depending on the location. The traffic terminals include, for example, signal control devices, guide boards, vehicle detectors, and vehicle number readers. The central unit estimates traffic conditions on the road network (such as sections where congestion occurs and travel times between two predetermined points) based on detection data transmitted from the vehicle detectors, vehicle number readers, and the like. The central unit also transmits display data for guidance (messages) to the guide boards to notify drivers of the estimated traffic conditions, and transmits signal control parameters to the signal control devices to improve the traffic conditions (for example, to suppress the occurrence of congestion).

[0003] Because the traffic control system has a large number of traffic terminals installed on the road network, the traffic terminals are divided into groups and a terminal-compatible device is assigned to each group. The terminal-compatible device controls the transmission and reception of data (data communication) between the traffic terminals belonging to the assigned group and the central device. Specifically, the terminal-compatible device relays data transmitted and received between the traffic terminals and the central device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3456170 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even when the central unit and transportation terminals are operating normally, if a failure occurs in a terminal-compatible device, data cannot be transmitted or received between the central unit and the transportation terminal assigned to the failed terminal-compatible device. For example, the central unit loses detection data from vehicle detectors, vehicle number readers, and other devices assigned to the failed terminal-compatible device, reducing the accuracy of estimating traffic conditions in the road network (such as whether a traffic jam has occurred and how long the traffic jam will last). Furthermore, the central unit cannot transmit display data for guide signs assigned to the failed terminal-compatible device or signal control parameters to signal control devices assigned to the failed terminal-compatible device.

[0006] As described above, in conventional traffic control systems, even when the central unit and traffic terminals are operating normally, if a failure occurs in a terminal-compatible device, the traffic situation on the road network cannot be managed properly. Also, as mentioned above, traffic control systems have a large number of terminal-compatible devices because they assign a terminal-compatible device to each group into which traffic terminals are divided. Therefore, failures occur in one of the terminal-compatible devices with some frequency.

[0007] An object of the present invention is to provide a technique for preventing a situation in which a central device is unable to properly manage traffic on a road network. [Means for solving the problem]

[0008] To achieve the above objectives, the traffic control system is configured as follows:

[0009] The central device manages the traffic conditions on the road network by utilizing multiple traffic terminals installed on the road network. There are various types of traffic terminals, such as signal control devices, guide boards, vehicle detectors, and vehicle number readers. Different types of traffic terminals are installed on the road network according to their installation locations.

[0010] The router is connected to transportation terminals installed in the road network via communication lines. These communication lines may be public lines or dedicated lines. Furthermore, the communication lines may be wired or wireless.

[0011] The first terminal-compatible device and the second terminal-compatible device are connected to the central device via a first network, and are connected to a router via a second network different from the first network. The first terminal-compatible device and the second terminal-compatible device perform a transmission / reception process for transmitting and receiving data between the central device and the transportation terminal via the router.

[0012] The first terminal corresponding device includes a main system operation control unit that executes transmission and reception processing when in a first state where a standby instruction has not been notified from the second terminal corresponding device, and stops (does not execute) transmission and reception processing when in a second state where a standby instruction has been notified from the second terminal corresponding device.

[0013] Furthermore, the second terminal corresponding device includes a slave operation control unit. This slave operation control unit performs a communication check to confirm whether the central device and the first terminal corresponding device are connected via the first network. If the slave operation control unit can confirm that the central device is connected via the first network but cannot confirm that the first terminal corresponding device is connected via the first network, it assumes that some kind of failure has occurred in the first terminal corresponding device and starts transmission and reception processing. Furthermore, even after starting the transmission and reception processing, the second terminal corresponding device continues to check whether it is connected to the first terminal corresponding device via the first network using the communication check, and when it can confirm that it is connected to the first terminal corresponding device via the first network, it notifies the first terminal corresponding device of a standby instruction.

[0014] In this configuration, the second terminal-compatible device checks whether it is connected to the central device and the first terminal-compatible device via the first network, thereby determining whether a failure has occurred in the central device but not in the first terminal-compatible device. When the second terminal-compatible device determines that a failure has occurred in the central device but not in the first terminal-compatible device, it starts transmission and reception processing. In other words, the second terminal-compatible device performs transmission and reception processing in place of the failed first terminal-compatible device, thereby preventing interruptions in data transmission and reception between the central device and the transportation terminal. This prevents a situation in which data transmission and reception between the central device and the transportation terminal is not possible, preventing the central device from being unable to properly manage traffic conditions in the road network.

[0015] Furthermore, after starting transmission / reception processing, if the second terminal corresponding device confirms that it is connected to the first terminal corresponding device via the first network, it notifies the first terminal corresponding device of a standby instruction, which causes the first terminal corresponding device to stop transmission / reception processing. This prevents both the first terminal corresponding device and the second terminal corresponding device from simultaneously performing transmission / reception processing, which could cause instability in the operation of the transportation terminal or unnecessary increases in traffic on the communication line connecting the router and the transportation terminal.

[0016] In addition, the slave operation control unit of the second terminal corresponding device may be configured to notify a standby instruction to the first terminal corresponding device if it can confirm that it is connected to the first terminal corresponding device via the second network, even if it cannot confirm that it is connected to the first terminal corresponding device via the first network after starting the transmission / reception process.

[0017] With this configuration, even if there is a connection problem between the first terminal corresponding device and the second terminal corresponding device in the first network, the second terminal corresponding device can use the second network to notify the first terminal corresponding device of a standby instruction.

[0018] In addition, the traffic control system can also be configured as follows to achieve the above object.

[0019] The configurations that differ from the above example are (a) and (b) shown below. (a) The slave operation control unit of the second terminal corresponding device performs a communication check to confirm whether or not the central device and the first terminal corresponding device are connected via the second network. If the slave operation control unit can confirm that the central device is connected via the second network but cannot confirm that the first terminal corresponding device is connected via the second network, it assumes that some kind of failure has occurred in the first terminal corresponding device and starts transmission and reception processing.

[0020] (b) Furthermore, even after starting the transmission / reception process, the slave operation control unit of the second terminal corresponding device checks whether it is connected to the first terminal corresponding device via the second network by performing a communication confirmation, and when it is confirmed that it is connected to the first terminal corresponding device via the second network, it notifies the first terminal corresponding device of a standby instruction.

[0021] As with the above example, this configuration can also reduce the frequency of situations where traffic on a road network cannot be managed appropriately. It can also prevent both the first terminal corresponding device and the second terminal corresponding device from simultaneously performing transmission and reception processing, which can cause the operation of the transportation terminal to become unstable or unnecessarily increase traffic on the communication line connecting the router and the transportation terminal.

[0022] In addition, in this configuration example, even if the slave operation control unit cannot confirm that the first terminal corresponding device is connected to the second network after starting the transmission / reception process, if it can confirm that the first terminal corresponding device is connected to the first network, the slave operation control unit may be configured to notify the first terminal corresponding device of a standby instruction.

[0023] Furthermore, the traffic control system can also be configured as shown below to achieve the above object. This example is a combination of the above two examples.

[0024] In this example, the slave operation control unit of the second terminal corresponding device performs a communication check with each of the central device and the first terminal corresponding device connected via the first network, and also performs a communication check with each of the router and the first terminal corresponding device connected via the second network.If it can confirm that it is connected to the central device and the router, but cannot confirm that it is connected to the first terminal corresponding device via the first network or the second network, it is configured to start transmission and reception processing.

[0025] This configuration can more reliably reduce the frequency of situations where traffic on the road network cannot be managed appropriately. It also prevents both the first terminal corresponding device and the second terminal corresponding device from simultaneously performing transmission and reception processing, which can cause the operation of the transportation terminal to become unstable or unnecessarily increase traffic on the communication line connecting the router and the transportation terminal.

[0026] Furthermore, the primary operation control unit may be configured to return to the first state when a non-standby instruction is input. In other words, the primary operation control unit may be configured to continue halting transmission and reception processing until a non-standby instruction is input. In this case, for example, if the secondary operation control unit of the second terminal corresponding device is configured to notify the first terminal corresponding device of a non-standby instruction when a notification of recovery completion of the first terminal corresponding device is input after notifying the first terminal corresponding device of a standby instruction, it is possible to more reliably prevent both the first terminal corresponding device and the second terminal corresponding device from performing transmission and reception processing simultaneously.

[0027] In addition, the slave operation control unit of the second terminal corresponding device may be configured to stop the ongoing transmission / reception process when a standby instruction is sent to the first terminal corresponding device and a completion of recovery of the first terminal corresponding device is input. [Effects of the Invention]

[0028] According to this invention, it is possible to prevent a situation in which the central device is unable to properly manage traffic on a road network. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a schematic diagram illustrating a traffic control system according to this example. [Figure 2] FIG. 2 is a diagram showing connections between a master terminal corresponding device, a slave terminal corresponding device, and a router that belong to the same group. [Figure 3] FIG. 2 is a block diagram showing the configuration of the main part of the main terminal corresponding device of this example. [Figure 4] 1 is a block diagram showing the configuration of the main part of a slave terminal corresponding device of this example. [Figure 5] 10 is a flowchart showing the operation of the main terminal corresponding device. [Figure 6] 10 is a flowchart showing the operation of a slave terminal corresponding device. [Figure 7] 10 is a flowchart showing the operation of a slave terminal corresponding device. [Figure 8] 10 is a flowchart showing the operation of the main terminal corresponding device of the second modification. [Figure 9] 10 is a flowchart showing the operation of a slave terminal corresponding device of Modification 2. [Figure 10] 10 is a flowchart showing the operation of a slave terminal corresponding device of Modification 2. [Figure 11] 13 is a flowchart showing the operation of the main terminal corresponding device of the fourth modified example. [Figure 12] 13 is a flowchart showing the operation of a slave terminal corresponding device of Modification 4. [Figure 13] 13 is a flowchart showing the operation of a slave terminal corresponding device of Modification 4. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, an embodiment of the present invention will be described.

[0031] <1. Application Examples> 1 is a schematic diagram showing a traffic control system of this example. The traffic control system 1 of this example includes a central device 2, a master terminal corresponding device 3, a slave terminal corresponding device 4, a router 5, and a traffic terminal 6.

[0032] In this example, the traffic control system 1 has traffic terminals 6 installed at multiple points on the roads that make up the road network, with types of traffic terminals 6 corresponding to the points. As shown in FIG. 1, the traffic terminals 6 are divided into multiple groups (groups g1 to gn). For example, the road network is divided into multiple areas, and these areas are grouped into traffic terminals 6 (traffic terminals 6 installed in the same area are grouped together). The traffic terminals 6 are not of a specific type. Examples of traffic terminals 6 are signal control devices, information boards, vehicle detectors, and vehicle number readers. The traffic terminals 6, such as signal control devices, information boards, vehicle detectors, and vehicle number readers, are well known, so only a brief explanation will be given here.

[0033] Traffic light control devices control the switching of light colors (red, yellow, green, etc.) of traffic lights installed at intersections, etc. Guide boards display traffic information and other information to notify drivers. Vehicle detectors detect the presence or absence of vehicles within their detection areas. Vehicle number readers read the license plate numbers written on the license plates of vehicles passing through the target area.

[0034] The traffic terminal 6 may be of a type other than the above-mentioned signal control device, guide board, vehicle detector, and vehicle number reader.

[0035] The central device 2, the master terminal corresponding device 3, the slave terminal corresponding device 4, and the router 5 are installed in a traffic control center. In this example, the traffic control system 1 has groups G1 to Gn, each of which includes a master terminal corresponding device 3, a slave terminal corresponding device 4, and a router 5, for each of groups g1 to gn of traffic terminals 6. In this example, the master terminal corresponding device 3 corresponds to the first terminal corresponding device in this invention, and the slave terminal corresponding device 4 corresponds to the second terminal corresponding device in this invention.

[0036] 2 is a diagram showing the connection of a master terminal corresponding device 3, a slave terminal corresponding device 4, and a router 5 that belong to the same groups G1 to Gn. The master terminal corresponding device 3 and the slave terminal corresponding device 4 are connected to the central device 2 via an upper network 11 (e.g., a LAN). The master terminal corresponding device 3 and the slave terminal corresponding device 4 are connected to the router 5 via a lower network 12 (e.g., a LAN). In this example, the upper network 11 corresponds to the first network as referred to in this invention, and the lower network 12 corresponds to the second network as referred to in this invention.

[0037] The master terminal corresponding device 3 operates in a non-standby state unless it has received a standby instruction from the slave terminal corresponding device 4, and operates in a standby state unless it has received a standby instruction from the slave terminal corresponding device 4. The non-standby state corresponds to the first state in this invention, and the standby state corresponds to the second state in this invention. When in a non-standby state, the master terminal corresponding device 3 performs a transmission / reception process that controls the transmission and reception of data between the central device 2 and the transportation terminals 6 of the corresponding groups g1 to gn. The master terminal corresponding device 3 transmits and receives data to and from the central device 2 via the upper network 11. The master terminal corresponding device 3 transmits and receives data to and from the router 5 via the lower network 12. The router 5 communicates with the transportation terminals 6 of the corresponding groups g1 to gn via a communication line 10.

[0038] The router 5 can transmit data to a specific transportation terminal 6 (transportation terminal 6 with a specified ID) by specifying the ID of the transportation terminal 6 to which the data is to be transmitted. Also, although the traffic control system 1 in the example shown in Fig. 1 is configured to have a router 5 for each group G1 to Gn, the router 5 may be shared by multiple groups G1 to Gn.

[0039] Furthermore, when the main terminal corresponding device 3 is in standby mode, it stops the transmission / reception process that controls the transmission and reception of data between the central device 2 and the transportation terminals 6 of the corresponding groups g1 to gn. The main terminal corresponding device 3 has a storage unit (a state storage unit 31b, described later) that stores state management information that indicates whether the current state is a non-standby state or a standby state.

[0040] The slave terminal corresponding device 4 periodically (e.g., at intervals of several tens of seconds to several minutes) performs a communication check to check whether it is connected to the central device 2 and the master terminal corresponding device 3 via the upper network 11. In this communication check, for example, the slave terminal corresponding device 4 transmits a response request (e.g., a Ping command) to each of the central device 2 and the master terminal corresponding device 3 via the upper network 11. If the slave terminal corresponding device 4 receives a response to the response request from the central device 2 via the upper network 11, it determines that it is connected to the central device 2 via the upper network 11. In other words, if the slave terminal corresponding device 4 does not receive a response to the response request from the central device 2 via the upper network 11, it determines that it is not connected to the central device 2 via the upper network 11. Similarly, if the slave terminal corresponding device 4 receives a response to the response request from the master terminal corresponding device 3 via the upper network 11, it determines that it is connected to the master terminal corresponding device 3 via the upper network 11. In other words, if there is no response to the response request from the master terminal corresponding device 3 through the upper network 11, the slave terminal corresponding device 4 determines that it is not connected to the master terminal corresponding device 3 via the upper network 11.

[0041] If the slave terminal corresponding device 4 can confirm in the communication check that it is connected to the central device 2 on the upper network 11, but cannot confirm that it is connected to the main terminal corresponding device 3 on the upper network 11, it starts a transmission / reception process that controls the transmission and reception of data between the central device 2 and the transportation terminal 6 of the corresponding group g1 to gn. If the slave terminal corresponding device 4 can confirm in the communication check that it is connected to the main terminal corresponding device 3 on the upper network 11, or cannot confirm that it is connected to the central device 2 on the upper network 11, it does not start a transmission / reception process that controls the transmission and reception of data between the central device 2 and the transportation terminal 6 of the corresponding group g1 to gn.

[0042] Even after starting the transmission / reception process that controls the transmission and reception of data between the central device 2 and the transportation terminals 6 of the corresponding groups g1 to gn, the slave terminal corresponding device 4 periodically performs a communication check to check whether it is connected to the master terminal corresponding device 3 via the upper network 11. When the slave terminal corresponding device 4 confirms that it is connected to the master terminal corresponding device 3 via the upper network 11, it notifies the master terminal corresponding device 3 of a standby instruction via the upper network 11.

[0043] When the master terminal corresponding device 3 receives a standby instruction from the slave terminal corresponding device 4, it updates the stored status management information from a non-standby state to a standby state, and stops the transmission / reception process that controls the transmission and reception of data between the central device 2 and the transportation terminals 6 of the corresponding groups g1 to gn. In other words, when the master terminal corresponding device 3 receives a standby instruction from the slave terminal corresponding device 4, it transitions from a non-standby state to a standby state.

[0044] In this example, in order to prevent interruption of data transmission and reception between the central device 2 and the traffic terminals 6 of the corresponding groups g1 to gn due to a failure in the master terminal corresponding device 3, the slave terminal corresponding device 4 performs transmission and reception processing in place of the failed first terminal corresponding device. This prevents the central device 2 from being unable to properly manage traffic on the road network.

[0045] Furthermore, after starting transmission / reception processing, if the slave terminal corresponding device 4 confirms that it is connected to the master terminal corresponding device 3 via the upper network 11, it notifies the master terminal corresponding device 3 of a standby instruction. This prevents both the master terminal corresponding device 3 and the slave terminal corresponding device 4 from simultaneously performing transmission / reception processing, which could destabilize the operation of the transportation terminal 6 or unnecessarily increase traffic on the communication line connecting the router 5 and the transportation terminal 6.

[0046] <2.Configuration example> 3 is a block diagram showing the main components of the master terminal corresponding device of this example. The master terminal corresponding device 3 comprises a master control unit 31, a host network connection unit 32, and a subordinate network connection unit 33.

[0047] The master control unit 31 controls the operation of each unit in the main body of the master terminal corresponding device 3. The master control unit 31 also has a transmission / reception processing execution unit 31a and a status storage unit 31b. The transmission / reception processing execution unit 31a and the status storage unit 31b of the master control unit 31 will be described later.

[0048] The upper network connection unit 32 is connected to the upper network 11. The master terminal corresponding device 3 is an interface that performs data communication between the central device 2 and the slave terminal corresponding device 4 connected by the upper network 11.

[0049] The downstream network connection unit 33 is connected to the downstream network 12. The master terminal corresponding device 3 is an interface for performing data communication with the slave terminal corresponding device 4 and the router 5 connected by the downstream network 12.

[0050] Next, we will explain the transmission / reception processing execution unit 31a and status storage unit 31b that the master control unit 31 has. The transmission / reception processing execution unit 31a controls the transmission and reception of data between the central device 2 and the transportation terminal 6. The master terminal corresponding device 3 transmits and receives data between the central device 2 and the transportation terminal 6 using a router 5. The status storage unit 31b stores status management information that indicates whether the master terminal corresponding device 3 is in a non-standby state where a standby instruction has not been sent from the slave terminal corresponding device 4, or in a standby state where a standby instruction has been sent from the slave terminal corresponding device 4.

[0051] The master control unit 31 of the master terminal corresponding device 3 is composed of a hardware CPU, memory, and other electronic circuits. When the hardware CPU executes a pre-installed master operation program, it operates as a transmission / reception processing execution unit 31a. The memory also has an area for expanding the master operation program and an area for temporarily storing data generated during execution of the master operation program. A portion of the memory storage area is also used as a status storage unit 31b. The master control unit 31 may be an LSI that integrates the hardware CPU, memory, etc.

[0052] 4 is a block diagram showing the main components of the slave terminal corresponding device of this example. The slave terminal corresponding device 4 comprises a slave control unit 41, an upper network connection unit 42, and a lower network connection unit 43.

[0053] The slave control unit 41 controls the operation of each unit in the main body of the slave terminal corresponding device 4. The slave control unit 41 also has a transmission / reception process execution unit 41a, a state storage unit 41b, and a state estimation unit 41c. The transmission / reception process execution unit 41a, the state storage unit 41b, and the state estimation unit 41c that the slave control unit 41 has will be described later.

[0054] The upper network connection unit 42 is connected to the upper network 11. The slave terminal corresponding device 4 is an interface that performs data communication between the central device 2 and the master terminal corresponding device 3 that are connected by the upper network 11.

[0055] The downstream network connection unit 43 is connected to the downstream network 12. The slave terminal corresponding device 4 is an interface for performing data communication between the master terminal corresponding device 3 connected by the downstream network 12 and the router 5.

[0056] Next, the transmission / reception processing execution unit 41a, status memory unit 41b, and status estimation unit 41c of the slave control unit 41 will be described. The transmission / reception processing execution unit 41a controls the transmission and reception of data between the central device 2 and transportation terminal 6. The slave terminal corresponding device 4 transmits and receives data between the central device 2 and transportation terminal 6 using a router 5. The status memory unit 41b stores status management information indicating whether a failure has occurred in the master terminal corresponding device 3 and whether a standby instruction has been sent to the master terminal corresponding device 3. The status estimation unit 41c estimates whether a failure has occurred in the master terminal corresponding device 3.

[0057] The slave control unit 41 of the slave terminal corresponding device 4 is composed of a hardware CPU, memory, and other electronic circuits. When the hardware CPU executes a pre-installed slave operation program, it operates as a transmission / reception processing execution unit 41a. The memory also has an area for expanding the slave operation program and an area for temporarily storing data and the like generated when the slave operation program is executed. A part of the memory storage area is also used as a status storage unit 41b. The slave control unit 41 may be an LSI that integrates the hardware CPU, memory, and the like.

[0058] The central unit 2 manages the traffic conditions in the road network by utilizing multiple traffic terminals 6 installed in the road network. The central unit 2 estimates the traffic conditions in the road network (sections where congestion occurs, travel time between two predetermined points, etc.) based on detection data transmitted from traffic terminals 6 such as vehicle detectors and vehicle number readers. The central unit 2 also transmits guidance display data to guide boards to notify drivers of the estimated traffic conditions, and transmits signal control parameters to signal control devices to improve the traffic conditions (for example, to suppress the occurrence of traffic congestion). The guide boards and signal control devices are also traffic terminals 6.

[0059] The router 5 is well known and will not be described in detail here.

[0060] <3. Example of operation> The operation of the traffic control system 1 in this example will be described below. The operation will be described assuming that the traffic control system 1 is in an initial state. The initial state is a state in which the master terminal corresponding device 3 is in a non-standby state executing a transmission / reception process that controls the transmission and reception of data between the central device 2 and the traffic terminal 6, and the slave terminal corresponding device 4 determines that it is connected to the central device 2 and the master terminal corresponding device 3 via the upper network 11.

[0061] First, a brief description will be given of the flow of data transmitted and received between the central device 2 and the traffic terminal 6 in the traffic control system 1 of this example.

[0062] First, we will explain the data transmitted from the central device 2 to the transportation terminal 6. When the traffic control system 1 in this example is in its initial state, the central device 2 transmits data to be sent to the transportation terminal 6 to the main terminal corresponding device 3 and the secondary terminal corresponding device 4 via the upper network 11. The main terminal corresponding device 3 transmits the data transmitted from the central device 2 (data to be sent to the transportation terminal 6) to the router 5 via the lower network 12. The router 5 transmits the data transmitted from the main terminal corresponding device 3 (data to be sent to the transportation terminal 6) to the transportation terminal 6 via the communication line 10. At this time, the secondary terminal corresponding device 4 does not transmit the data transmitted from the central device 2 (data to be sent to the transportation terminal 6) to the router 5.

[0063] When the central device 2 transmits data to a specific transportation terminal 6, it transmits the ID of the destination transportation terminal 6 together with the data to the main terminal corresponding device 3 via the upper network 11.

[0064] Next, we will explain the data transmitted from the transportation terminal 6 to the central device 2. When the traffic control system 1 in this example is in the initial state, the transportation terminal 6 transmits data to be sent to the central device 2 to the router 5 via the communication line 10. The router 5 transmits the data transmitted from the transportation terminal 6 (data to be sent to the central device 2) to the main terminal corresponding device 3 and the secondary terminal corresponding device 4 via the lower network 12. The main terminal corresponding device 3 transmits the data transmitted from the router 5 (data to be sent to the central device 2) to the central device 2 via the upper network 11. At this time, the secondary terminal corresponding device 4 does not transmit the data transmitted from the router 5 (data to be sent to the central device 2) to the central device 2.

[0065] It should be noted that the transmission and reception of data between the router 5 and the traffic terminal 6 is the same regardless of whether the traffic control system 1 of this example is in the initial state or not.

[0066] Fig. 5 is a flowchart showing the operation of the master terminal corresponding device, and Fig. 6 and Fig. 7 are flowcharts showing the operation of the slave terminal corresponding device.

[0067] 5, the main terminal corresponding device 3 is in a non-standby state, and is executing a transmission / reception process to control transmission and reception of data between the central device 2 and the transportation terminal 6. The status management information stored in the status memory unit 31b of the main terminal corresponding device 3 is in a non-standby state.

[0068] 6 and 7, the slave terminal corresponding device 4 determines that it is connected to the central device 2 and the master terminal corresponding device 3 via the upper network 11. The status management information stored in the status storage unit 41b of the slave terminal corresponding device 4 indicates that a failure in the master terminal corresponding device 3 has not been detected and that a standby instruction has not been sent.

[0069] The master terminal corresponding device 3 waits to receive a response request from the slave terminal corresponding device 4 or to receive a standby instruction from the slave terminal corresponding device 4 (s1, s2). At this time, the master terminal corresponding device 3 executes a transmission / reception process that controls the transmission and reception of data between the central device 2 and the transportation terminal 6. This transmission / reception process is a data relay process in which, when data to be transmitted to the transportation terminal 6 is received from the central device 2, the master terminal corresponding device 3 transmits this data to the router 5, and, when data to be transmitted to the central device 2 is received from the router 5, the master terminal corresponding device 3 transmits this data to the central device 2.

[0070] When the timing for confirming communication arrives, the slave terminal corresponding device 4 executes a response request transmission process to transmit a response request to the central device 2 and the master terminal corresponding device 3 connected via the upper network 11 (s11, s12). The communication confirmation timing is set at intervals of, for example, several tens of seconds to several minutes. The slave terminal corresponding device 4 transmits the response request through the upper network 11.

[0071] When the master terminal corresponding device 3 receives the response request from the slave terminal corresponding device 4, it performs a response process to respond to this response request (s3) and returns to s1. The master terminal corresponding device 3 transmits a response to the response request to the slave terminal corresponding device 4 through the upper network 11.

[0072] Similarly to the master terminal corresponding device 3, the central device 2 also performs a response process to respond to the response request when it receives a response request from the slave terminal corresponding device 4. Specifically, similar to the master terminal corresponding device 3, the central device 2 also transmits a response to the response request to the slave terminal corresponding device 4 through the upper network 11.

[0073] The slave terminal corresponding device 4 determines whether there is a response from the central device 2 to the response request sent through the upper network 11 in s12 (s13), and if it determines that there is no response, returns to s11. The slave terminal corresponding device 4 may determine that there is no response from the central device 2 when, for example, a fault occurs in the central device 2, the slave terminal corresponding device 4 is disconnected from the upper network 11, or the central device 2 is disconnected from the upper network 11. In other words, even if the slave terminal corresponding device 4 performs transmission and reception processing in place of the master terminal corresponding device 3, data cannot be transmitted or received between the central device 2 and the transportation terminal 6.

[0074] If the slave terminal corresponding device 4 determines in s13 that there has been a response from the central device 2 to the response request, it determines whether there has been a response from the master terminal corresponding device 3 to this response request (s14). If the slave terminal corresponding device 4 determines in s14 that there has been a response from the master terminal corresponding device 3, it returns to s11. If the slave terminal corresponding device 4 determines in s14 that there has been no response from the master terminal corresponding device 3, it starts transmission / reception processing (s15).

[0075] The slave terminal corresponding device 4 may proceed to s15 if it determines that there is no response from the master terminal corresponding device 3 a set number of times (for example, 2 to 5 times) in succession, or may proceed to s15 if the ratio (m / n) of the number of times m that it has determined that there is no response from the master terminal corresponding device 3 in the most recent n times exceeds a set value (for example, 0.5).

[0076] The circumstances in which the slave terminal corresponding device 4 determines that there is no response to the response request from the master terminal corresponding device 3 include, for example, a situation in which a failure occurs in the master terminal corresponding device 3, or a situation in which the master terminal corresponding device 3 is disconnected from the upper network 11. Furthermore, since the slave terminal corresponding device 4 determines that there is a response from the central device 2 in s13, the central device 2 and the slave terminal corresponding device 4 are connected to the upper network 11 and are operating properly without any failure. In other words, if the slave terminal corresponding device 4 executes the transmission and reception process in place of the master terminal corresponding device 3, data can be transmitted and received between the central device 2 and the transportation terminal 6.

[0077] When the slave terminal corresponding device 4 starts the transmission / reception process in s15, it updates the status management information stored in the status storage unit 41b (s16) and waits for the timing of communication confirmation or input of recovery completion (s17, s18). In s16, the slave terminal corresponding device 4 updates the status management information stored in the status storage unit 41b to indicate that a failure has been detected in the master terminal corresponding device 3 and that a standby instruction has not been issued. The slave terminal corresponding device 4 may be configured such that an operator operates an operation unit (not shown) to input information related to recovery completion, or may be configured such that a notification (input) related to recovery completion is received from the central device 2 via the upper network 11, or may have other configurations. The notification (input) related to recovery completion may be input by an operator on the operation unit of the device itself, or may be received from another device (such as the central device 2, the master terminal corresponding device 3, or the router 5).

[0078] Furthermore, if the slave terminal corresponding device 4 determines in s18 that an input indicating completion of recovery has been received, the process proceeds to s24, which will be described later.

[0079] Furthermore, when the slave terminal corresponding device 4 determines in s17 that it is time to check communication, it transmits a response request to the connected master terminal corresponding device 3 (s19). This response request is transmitted to the master terminal corresponding device 3 through the upper network 11. In s19, as in s12, the response request may be transmitted not only to the master terminal corresponding device 3 but also to the central device 2. However, the processing from s20 onwards of the slave terminal corresponding device 4 in this example is the same regardless of whether or not a response is received from the central device 2.

[0080] As described above, when the master terminal corresponding device 3 receives a response request from the slave terminal corresponding device 4, it responds to this response request at s3.

[0081] The slave terminal corresponding device 4 determines whether there is a response from the master terminal corresponding device 3 to the response request sent through the upper network 11 in s19 (s20), and if it determines that there is no response, returns to s17.

[0082] When the slave terminal corresponding device 4 determines in s20 that there has been a response from the master terminal corresponding device 3, it notifies the master terminal corresponding device 3 of a standby instruction through the upper network 11 (s21). The slave terminal corresponding device 4 also updates the status management information stored in the status storage unit 41b (s22). In s22, the slave terminal corresponding device 4 updates the status management information stored in the status storage unit 41b to indicate that a failure has been detected in the master terminal corresponding device 3 and that a standby instruction has been notified.

[0083] When the master terminal corresponding device 3 receives a standby instruction from the slave terminal corresponding device 4, it stops transmission and reception processing (s2, s4). The master terminal corresponding device 3 also updates the status management information stored in the status storage unit 31b to a standby status (s5) and waits for a non-standby instruction to be input (s6). This non-standby instruction may be input by a notification from the central device 2, by a notification from the slave terminal corresponding device 4, or by an input operation by an operator. In this example, the non-standby instruction is notified from the slave terminal corresponding device 4 to the master terminal corresponding device 3.

[0084] The slave terminal corresponding device 4 waits for an input indicating recovery completion in s15 or s23. If the slave terminal corresponding device 4 determines that an input indicating recovery completion has been received in s15 or s23, it transmits a non-standby instruction to the master terminal corresponding device 3 through the upper network 11 (s24). After transmitting the non-standby instruction to the master terminal corresponding device 3 in s24, the slave terminal corresponding device 4 waits for a recovery completion instruction to be received from the master terminal corresponding device 3 (s25).

[0085] When the master terminal corresponding device 3 determines that a non-standby instruction has been input in s6, it updates the state stored in the state storage unit 31b to a non-standby state (s7). In s7, it updates the state management information stored in the state storage unit 31b from a standby state to a non-standby state. The master terminal corresponding device 3 transmits a recovery completion notice to the slave terminal corresponding device 4 (s8), and starts the transmission / reception process stopped in s4 (s9), and returns to s1.

[0086] When the slave terminal corresponding device 4 receives the restoration completion notice from the master terminal corresponding device 3 in s25, it stops the transmission / reception process started in s15 (s26). The slave terminal corresponding device 4 also updates the status management information stored in the status storage unit 41b (s27) and returns to s11. In s27, the slave terminal corresponding device 4 updates the status management information stored in the status storage unit 41b to indicate that a failure in the master terminal corresponding device 3 has not been detected and that a standby instruction has not been sent.

[0087] In this way, in the traffic control system 1 of this example, in order to prevent interruption of data transmission and reception between the central device 2 and the traffic terminals 6 of the corresponding groups g1 to gn due to a failure in the main terminal corresponding device 3, the secondary terminal corresponding device 4 performs transmission and reception processing on behalf of the main terminal corresponding device 3. This makes it possible to prevent a situation in which the central device 2 is unable to properly manage traffic on the road network.

[0088] Furthermore, after starting transmission / reception processing, if the slave terminal corresponding device 4 confirms that it is connected to the master terminal corresponding device 3 via the upper network 11, it notifies the master terminal corresponding device 3 of a standby instruction. This prevents both the master terminal corresponding device 3 and the slave terminal corresponding device 4 from simultaneously performing transmission / reception processing, which could destabilize the operation of the transportation terminal 6 or unnecessarily increase traffic on the communication line 10 connecting the router 5 and the transportation terminal 6.

[0089] Furthermore, the slave terminal corresponding device 4 is configured not to execute a communication check while the master terminal corresponding device 3 is in a standby state (while the status management information stored in the status storage unit 41b indicates that a standby instruction has been sent). This makes it possible to reduce the processing load on the slave terminal corresponding device 4.

[0090] <4. Modifications> Variation 1 In this modified example 1, the slave terminal corresponding device 4 transmits a response request to the connected master terminal corresponding device 3 through the upper network 11 in s19, and also transmits a response request to the connected master terminal corresponding device 3 through the lower network 12. Furthermore, when the slave terminal corresponding device 4 receives a response from the master terminal corresponding device 3 through the upper network 11, it notifies the master terminal corresponding device 3 of a standby instruction through the upper network 11 in s21, and when it receives a response from the master terminal corresponding device 3 through the lower network 12, it notifies the master terminal corresponding device 3 of a standby instruction through the lower network 12 in s21.

[0091] In this variant 1, when a response is received from the main terminal corresponding device 3 through the upper network 11 and also from the main terminal corresponding device 3 through the lower network 12, in s21, a standby instruction is notified to the main terminal corresponding device 3 through either the upper network 11 or the lower network 12.

[0092] As a result, even if the master terminal corresponding device 3 has a connection failure with the upper network 11 (is disconnected from the upper network 11), a standby instruction can be quickly notified to the master terminal corresponding device 3. In other words, the transmission and reception processing in the master terminal corresponding device 3 can be quickly stopped. In addition, the processing load on the slave terminal corresponding device 4 can be further reduced.

[0093] Variation 2 The traffic control system 1 of this modified example 2 also has the configuration shown in FIGS.

[0094] Fig. 8 is a flowchart showing the operation of the master terminal corresponding device of Modification 2. Fig. 9 and Fig. 10 are flowcharts showing the operation of the slave terminal corresponding device of Modification 2.

[0095] 8, the main terminal corresponding device 3 is in a non-standby state, and is executing a transmission / reception process to control transmission and reception of data between the central device 2 and the transportation terminal 6. The status management information stored in the status memory unit 31b of the main terminal corresponding device 3 is in a non-standby state.

[0096] 9 and 10, the slave terminal corresponding device 4 determines that it is connected to the central device 2 and the master terminal corresponding device 3 via the upper network 11. The status management information stored in the status storage unit 41b of the slave terminal corresponding device 4 indicates that a failure in the master terminal corresponding device 3 has not been detected and that a standby instruction has not been sent.

[0097] The master terminal corresponding device 3 waits to receive a response request or a standby instruction from the slave terminal corresponding device 4 (s31, s32). The processing in s31 and s32 is similar to the processing in s1 and s2 in the above example, but differs in that it waits to receive a response request or a standby instruction through the lower-level network 12.

[0098] When the timing for confirming communication arrives, the slave terminal corresponding device 4 transmits a response request to the router 5 and the master terminal corresponding device 3 (s41, s42). In this modified example 2, the slave terminal corresponding device 4 does not transmit a response request to the central device 2. In s42, the slave terminal corresponding device 4 transmits a response request to the router 5 and the master terminal corresponding device 3 through the lower-level network 12.

[0099] When the master terminal corresponding device 3 receives the response request from the slave terminal corresponding device 4, it performs a response process to respond to this response request (s33) and returns to s31. The master terminal corresponding device 3 transmits a response to the response request to the slave terminal corresponding device 4 through the lower-level network 12.

[0100] Similarly to the master terminal corresponding device 3, when the router 5 receives a response request from the slave terminal corresponding device 4, it performs a response process to respond to this response request.

[0101] The slave terminal corresponding device 4 determines whether there is a response from the router 5 to the response request sent through the lower-level network 12 in s42 (s43), and if it determines that there is no response, returns to s41. The slave terminal corresponding device 4 may determine that there is no response to the response request from the router 5 when, for example, a fault occurs in the router 5, the slave terminal corresponding device 4 is disconnected from the lower-level network 12, or the router 5 is disconnected from the lower-level network 12. In other words, even if the slave terminal corresponding device 4 performs transmission and reception processing in place of the master terminal corresponding device 3, data cannot be transmitted or received between the central device 2 and the transportation terminal 6.

[0102] If the slave terminal corresponding device 4 determines in s43 that there has been a response from the router 5 to the response request, it determines whether there has been a response from the master terminal corresponding device 3 to the response request sent through the downstream network 12 in s42 (s44). If the slave terminal corresponding device 4 determines in s44 that there has been a response from the master terminal corresponding device 3, it returns to s41. If the slave terminal corresponding device 4 determines in s44 that there has been no response from the master terminal corresponding device 3, it starts transmission / reception processing (s45).

[0103] The slave terminal corresponding device 4 may proceed to s45 if it determines that there is no response from the master terminal corresponding device 3 a set number of times (for example, 2 to 5 times) in succession, or may proceed to s45 if the ratio (m / n) of the number of times it has determined that there is no response from the master terminal corresponding device 3 in the most recent n times exceeds a set value (for example, 0.5).

[0104] A situation in which the slave terminal corresponding device 4 does not receive a response to a response request from the master terminal corresponding device 3 means, for example, that a fault has occurred in the master terminal corresponding device 3 or that the master terminal corresponding device 3 has been disconnected from the lower-level network 12. Furthermore, since the slave terminal corresponding device 4 has determined in s43 that a response has been received from the router 5, the router 5 and the slave terminal corresponding device 4 are connected to the lower-level network 12 and are operating properly without any faults. In other words, if the slave terminal corresponding device 4 executes transmission and reception processing in place of the master terminal corresponding device 3, data can be transmitted and received between the central device 2 and the transportation terminal 6.

[0105] When the slave terminal corresponding device 4 starts the transmission / reception process in s45, it updates the status management information stored in the status storage unit 41b (s46) and waits for the timing of communication confirmation or input of recovery completion (s47, s48). S46 is the same as s16 in the above example.

[0106] Furthermore, if the slave terminal corresponding device 4 determines in s48 that an input indicating completion of recovery has been received, the process proceeds to s54, which will be described later.

[0107] Furthermore, when the slave terminal corresponding device 4 determines in s47 that it is time to check communication, it transmits a response request to the connected master terminal corresponding device 3 (s49). In s49, the slave terminal corresponding device 4 transmits the response request to the master terminal corresponding device 3 through the lower network 12. In s49, as in s12, the response request may be transmitted not only to the master terminal corresponding device 3 but also to the router 5. However, the processing from s50 onwards of the slave terminal corresponding device 4 in this example is the same regardless of whether or not a response is received from the router 5.

[0108] As described above, when the master terminal corresponding device 3 receives a response request from the slave terminal corresponding device 4, it responds to this response request in s33.

[0109] The slave terminal corresponding device 4 determines whether or not there is a response from the master terminal corresponding device 3 to the response request sent through the downstream network 12 in s49 (s50). If the slave terminal corresponding device 4 determines that there is no response, it returns to s47. If the slave terminal corresponding device 4 determines in s50 that there is a response from the master terminal corresponding device 3, it notifies the master terminal corresponding device 3 of a standby instruction through the downstream network 12 (s51). Furthermore, when the slave terminal corresponding device 4 notifies the master terminal corresponding device 3 of the standby instruction in s51, it updates the status management information stored in the status storage unit 41b (s52). The processing in s52 is the same as the processing in s22 in the example above.

[0110] When the master terminal corresponding device 3 receives a standby instruction from the slave terminal corresponding device 4, it stops transmission and reception processing (s32, s34). The master terminal corresponding device 3 also updates the status management information stored in the status storage unit 31b to a standby status (s35) and waits for a non-standby instruction to be input (s36). This non-standby instruction may be input by a notification from the central device 2, as in the above example, or by a notification from the slave terminal corresponding device 4, or may be input by an input operation by an operator. In this example, the non-standby instruction is notified from the slave terminal corresponding device 4 to the master terminal corresponding device 3.

[0111] When the master terminal corresponding device 3 determines in s36 that a non-standby instruction has been input, it updates the state stored in the state storage unit 31b to a non-standby state (s37). In s37, it updates the state management information stored in the state storage unit 31b from a standby state to a non-standby state. The master terminal corresponding device 3 transmits a recovery completion notice to the slave terminal corresponding device 4 (s38), restarts the transmission / reception process stopped in s34 (s39), and returns to s31.

[0112] When the slave terminal corresponding device 4 receives the restoration completion notice from the master terminal corresponding device 3 in s55, it stops the transmission / reception process started in s45 (s56). The slave terminal corresponding device 4 also updates the status management information stored in the status storage unit 41b (s57) and returns to s41. The process in s57 is the same as the process in s27 in the above example.

[0113] As is clear from the above description, the processing of steps s34 to s39 of the main terminal corresponding device 3 is similar to the processing of steps s4 to s9 in the above example.

[0114] The traffic control system 1 of this modified example 2 can also prevent the central device 2 from being unable to properly manage traffic on the road network. It can also prevent both the master terminal corresponding device 3 and the slave terminal corresponding device 4 from simultaneously performing transmission and reception processing, which could destabilize the operation of the transportation terminal 6 or unnecessarily increase traffic on the communication line 10 connecting the router 5 and the transportation terminal 6. It can also reduce the processing load on the slave terminal corresponding device 4.

[0115] Variation 3 In this modified example 3, the slave terminal corresponding device 4 transmits a response request to the connected master terminal corresponding device 3 through the upper network 11 in s49, and also transmits a response request to the connected master terminal corresponding device 3 through the lower network 12. Furthermore, when the slave terminal corresponding device 4 receives a response from the master terminal corresponding device 3 through the upper network 11, it notifies the master terminal corresponding device 3 of a standby instruction through the upper network 11 in s51, and when it receives a response from the master terminal corresponding device 3 through the lower network 12, it notifies the master terminal corresponding device 3 of a standby instruction through the lower network 12 in s51.

[0116] In this variant example 3, when a response is received from the main terminal corresponding device 3 through the upper network 11 and also from the main terminal corresponding device 3 through the lower network 12, in s51, a standby instruction is notified to the main terminal corresponding device 3 through either the upper network 11 or the lower network 12.

[0117] As a result, even if the master terminal corresponding device 3 has a connection failure with the lower network 12 (is disconnected from the lower network 12), a standby instruction can be quickly notified to the master terminal corresponding device 3. In other words, the transmission and reception processing in the master terminal corresponding device 3 can be quickly stopped. In addition, the processing load on the slave terminal corresponding device 4 can be reduced.

[0118] Variation 4 The traffic control system 1 of this fourth modification also has the configuration shown in FIGS.

[0119] Fig. 11 is a flowchart showing the operation of the master terminal corresponding device of Modification 4. Fig. 12 and Fig. 13 are flowcharts showing the operation of the slave terminal corresponding device of Modification 4.

[0120] 11, the main terminal corresponding device 3 is in a non-standby state, and is executing a transmission / reception process to control transmission and reception of data between the central device 2 and the transportation terminal 6. The status management information stored in the status memory unit 31b of the main terminal corresponding device 3 is in a non-standby state.

[0121] 12 and 13, the slave terminal corresponding device 4 determines that it is connected to the central device 2 and the master terminal corresponding device 3 via the upper network 11. The status management information stored in the status storage unit 41b of the slave terminal corresponding device 4 indicates that a failure in the master terminal corresponding device 3 has not been detected and that a standby instruction has not been sent.

[0122] The master terminal corresponding device 3 waits to receive a response request from the slave terminal corresponding device 4 through the upper network 11, or to receive a response request from the slave terminal corresponding device 4 through the lower network 12, or to receive a standby instruction from the slave terminal corresponding device 4 (s61 to s63). In s63, the master terminal corresponding device 3 waits to receive a standby instruction from the slave terminal corresponding device 4 through the upper network 11 or the lower network 12.

[0123] When the timing for confirming communication arrives, the slave terminal corresponding device 4 transmits a response request to the central device 2 and the master terminal corresponding device 3 through the upper network 11, and also transmits a response request to the router 5 and the master terminal corresponding device 3 through the lower network 12 (s81 to s83). In this modification 4, the slave terminal corresponding device 4 transmits a response request to the master terminal corresponding device 3 through the upper network 11, and also transmits it through the lower network 12.

[0124] When the master terminal corresponding device 3 receives a response request from the slave terminal corresponding device 4 transmitted through the upper network 11, it performs response processing to respond to this response request (s61, s64) and returns to s61. In s64, the master terminal corresponding device 3 transmits a response to the response request to the slave terminal corresponding device 4 through the upper network 11. Also, when the master terminal corresponding device 3 receives a response request from the slave terminal corresponding device 4 transmitted through the lower network 12, it performs response processing to respond to this response request (s62, s65) and returns to s61. In s65, the master terminal corresponding device 3 transmits a response to the response request to the slave terminal corresponding device 4 through the lower network 12.

[0125] When the central device 2 receives a response request from the slave terminal corresponding device 4 transmitted through the upper network 11, it performs response processing to transmit a response to the currently received response request to the slave terminal corresponding device 4 through the upper network 11. When the router 5 receives a response request from the slave terminal corresponding device 4 transmitted through the lower network 12, it performs response processing to transmit a response to the currently received response request to the slave terminal corresponding device 4 through the lower network 12.

[0126] The slave terminal corresponding device 4 determines whether or not there is a response from the central device 2 to the response request sent through the upper network 11 in s82 (s84). If the slave terminal corresponding device 4 determines in s84 that there is no response from the central device 2, it returns to s81. As described above, the slave terminal corresponding device 4 may determine that there is no response to the response request from the central device 2 when, for example, a fault occurs in the central device 2, the slave terminal corresponding device 4 is disconnected from the upper network 11, or the central device 2 is disconnected from the upper network 11. In other words, even if the slave terminal corresponding device 4 performs transmission and reception processing in place of the master terminal corresponding device 3, data cannot be transmitted or received between the central device 2 and the transportation terminal 6.

[0127] Furthermore, if the slave terminal corresponding device 4 determines in s84 that there is a response from the central device 2, it determines whether or not there is a response from the router 5 to the response request sent in s83 through the lower-level network 12 (s85). If the slave terminal corresponding device 4 determines in s85 that there is no response from the router 5, it returns to s81. As described above, the circumstances in which the slave terminal corresponding device 4 determines that there is no response from the router 5 to the response request include, for example, a situation in which a fault occurs in the router 5, a situation in which the slave terminal corresponding device 4 is disconnected from the lower-level network 12, or a situation in which the router 5 is disconnected from the lower-level network 12. In other words, even if the slave terminal corresponding device 4 performs transmission and reception processing in place of the master terminal corresponding device 3, data cannot be transmitted or received between the central device 2 and the transportation terminal 6.

[0128] When the slave terminal corresponding device 4 determines in s85 that there has been a response from the router 5 to the response request, it determines whether there has been a response from the master terminal corresponding device 3 to the response request sent through the upper network 11 in s82, and whether there has been a response from the master terminal corresponding device 3 to the response request sent through the lower network 12 in s83 (s86). In s86, if the slave terminal corresponding device 4 does not receive a response from the master terminal corresponding device 3 through the upper network 11 or if it does not receive a response through the lower network 12, it determines that there has been no response from the master terminal corresponding device 3. In other words, in s86, if the slave terminal corresponding device 4 receives a response from the master terminal corresponding device 3 through the upper network 11 and also receives a response through the lower network 12, it determines that there has been a response from the master terminal corresponding device 3.

[0129] If the slave terminal corresponding device 4 determines in s86 that there is a response from the master terminal corresponding device 3, it returns to s81. If the slave terminal corresponding device 4 determines in s86 that there is no response from the master terminal corresponding device 3, it starts transmission / reception processing (s87).

[0130] The slave terminal corresponding device 4 may proceed to s87 if it determines that there is no response from the master terminal corresponding device 3 a set number of times (for example, 2 to 5 times) in succession, or may proceed to s87 if the ratio (m / n) of the number of times m that it has determined that there is no response from the master terminal corresponding device 3 in the most recent n times exceeds a set value (for example, 0.5).

[0131] In the slave terminal corresponding device 4, a situation in which there is no response to the response request from the master terminal corresponding device 3 occurs when, for example, a fault occurs in the master terminal corresponding device 3, the master terminal corresponding device 3 is disconnected from the upper network 11, or the master terminal corresponding device 3 is disconnected from the lower network 12. In addition, since the slave terminal corresponding device 4 determines that there is a response from the central device 2 in s84 and that there is a response from the router 5 in s85, The central device 2 and the slave terminal corresponding device 4 are connected to a higher-level network 11, The router 5 and the slave terminal corresponding device 4 are connected to a lower-level network 12, Furthermore, the central device 2, the secondary terminal corresponding device 4, and the router 5 are operating properly without any failures. In other words, if the secondary terminal corresponding device 4 executes the transmission and reception process in place of the primary terminal corresponding device 3, data can be transmitted and received between the central device 2 and the transportation terminal 6.

[0132] When the slave terminal corresponding device 4 starts transmission / reception processing in s87, it determines whether there has been a response from the master terminal corresponding device 3 to the response request transmitted through the upper network 11 in s82, or whether there has been a response from the master terminal corresponding device 3 to the response request transmitted through the lower network 12 in s83 (s88, s89). If the slave terminal corresponding device 4 determines in s88 that there has been a response from the master terminal corresponding device 3, it notifies the master terminal corresponding device 3 of a standby instruction through the upper network 11 (s90). If the slave terminal corresponding device 4 determines in s89 that there has been a response from the master terminal corresponding device 3, it notifies the master terminal corresponding device 3 of a standby instruction through the lower network 12 (s90).

[0133] When the slave terminal corresponding device 4 notifies the master terminal corresponding device 3 of a standby instruction in s90, it updates the status management information stored in the status storage unit 41b (s91) and proceeds to s99. In s91, the slave terminal corresponding device 4 updates the status management information stored in the status storage unit 41b to indicate that a failure has been detected in the master terminal corresponding device 3 and that a standby instruction has been notified.

[0134] If the slave terminal corresponding device 4 determines in s88 that there has been no response from the master terminal corresponding device 3 and also determines in s89 that there has been no response from the master terminal corresponding device 3, it updates the status management information stored in the status storage unit 41b (s92) and proceeds to s93. In s92, the slave terminal corresponding device 4 updates the status management information stored in the status storage unit 41b to indicate that a failure has been detected in the master terminal corresponding device 3 and that a standby instruction has not been sent.

[0135] The slave terminal corresponding device 4 waits for a timing to confirm communication or an input indicating completion of restoration (s93, s94). If the slave terminal corresponding device 4 determines in s94 that an input indicating completion of restoration has been received, the process proceeds to s100, which will be described later.

[0136] Furthermore, when the slave terminal corresponding device 4 determines in s93 that it is time to check communication, it transmits a response request to the connected master terminal corresponding device 3 (s95). In s95, the slave terminal corresponding device 4 transmits a response request to the master terminal corresponding device 3 through the upper network 11, and also transmits a response request to the master terminal corresponding device 3 through the lower network 12. In s95, the response request may be transmitted not only to the master terminal corresponding device 3, but also to the central device 2 and the router 5. However, the processing from s97 onwards of the slave terminal corresponding device 4 in this example is the same regardless of whether or not a response is received from the central device 2 and the router 5.

[0137] As described above, when the master terminal corresponding device 3 receives a response request from the slave terminal corresponding device 4, it responds to this response request.

[0138] When the slave terminal corresponding device 4 sends a response request in s95, it determines whether there is a response from the master terminal corresponding device 3 to the response request sent through the upper network 11, or whether there is a response from the master terminal corresponding device 3 to the response request sent through the lower network 12 (s96). If the slave terminal corresponding device 4 determines in s96 that there is no response from the master terminal corresponding device 3 through the upper network 11 and that there is no response from the master terminal corresponding device 3 through the lower network 12, it returns to s93.

[0139] Furthermore, if the slave terminal corresponding device 4 determines in s96 that it has received a response from the master terminal corresponding device 3 through the upper network 11 or that it has received a response from the master terminal corresponding device 3 through the lower network 12, it notifies the master terminal corresponding device 3 of a standby instruction through the network (upper network 11 or lower network 12) through which the master terminal corresponding device 3 has responded this time. When the slave terminal corresponding device 4 notifies the master terminal corresponding device 3 of the standby instruction in s97, it updates the status management information stored in the status storage unit 41b (s98). In s98, the slave terminal corresponding device 4 updates the status management information stored in the status storage unit 41b to indicate that a failure has been detected in the master terminal corresponding device 3 and that a standby instruction has been notified.

[0140] When the master terminal corresponding device 3 receives the standby instruction from the slave terminal corresponding device 4, it stops the transmission and reception process (s63, s66). The master terminal corresponding device 3 also updates the status management information stored in the status storage unit 31b to a standby state (s67) and waits for a non-standby instruction to be input (s68). This non-standby instruction may be input by a notification from the central device 2, as in the above example, or by a notification from the slave terminal corresponding device 4, or may be input by an input operation by an operator. In this example, the non-standby instruction is notified from the slave terminal corresponding device 4 to the master terminal corresponding device 3.

[0141] The slave terminal corresponding device 4 waits for an input indicating the completion of recovery in s94 or s99. When the slave terminal corresponding device 4 determines that an input indicating the completion of recovery has been received in s94 or s99, it transmits a non-standby instruction to the master terminal corresponding device 3 through the upper network 11 or the lower network 12 (s100). In addition, the slave terminal corresponding device 4 The slave terminal corresponding device 4 transmits a non-standby instruction to the master terminal corresponding device 3 in s100, and then waits to receive a restoration completion notice from the master terminal corresponding device 3 (s101).

[0142] When the master terminal corresponding device 3 determines in s68 that a non-standby instruction has been input, it updates the status management information stored in the status storage unit 31b (s69). In s69, the status management information stored in the status storage unit 31b is updated from the standby state to the non-standby state. The master terminal corresponding device 3 transmits a recovery completion notice to the slave terminal corresponding device 4 (s70), restarts the transmission / reception process stopped in s66 (s71), and returns to s61.

[0143] When the slave terminal corresponding device 4 receives the restoration completion notice from the master terminal corresponding device 3 in s101, it stops the transmission / reception process started in s87 (s102). The slave terminal corresponding device 4 also updates the status management information stored in the status storage unit 41b (s103) and returns to s81. In s103, the slave terminal corresponding device 4 updates the status management information stored in the status storage unit 41b to indicate that a failure in the master terminal corresponding device 3 has not been detected and that a standby instruction has not been sent.

[0144] The traffic control system 1 of this modification 4 can also prevent the central device 2 from being unable to properly manage traffic on the road network. It can also prevent both the master terminal corresponding device 3 and the slave terminal corresponding device 4 from simultaneously performing transmission and reception processing, which could destabilize the operation of the transportation terminal 6 or unnecessarily increase traffic on the communication line 10 connecting the router 5 and the transportation terminal 6.

[0145] Furthermore, this invention is not limited to the above-described embodiments as they are, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined. Furthermore, the order of each step in the flowcharts described in all the above examples is merely an example, and may be appropriately changed within the scope of the present invention.

[0146] Furthermore, the correspondence between the configuration according to the present invention and the configuration according to the above-described embodiment can be described as follows: <Additional Notes> <Appendix 1> a central device (2) for managing traffic on a road network by utilizing a plurality of traffic terminals (6) installed on the road network; a router (5) connected to a traffic terminal (6) installed on the road network via a communication line (10); a first terminal corresponding device (3) and a second terminal corresponding device (4) that are connected to the central device (2) via a first network (11) and to the router (5) via a second network (12) different from the first network (11), and that perform transmission and reception processing for transmitting and receiving data between the central device (2) and the transportation terminal (6) via the router (5); The first terminal corresponding device (3) comprises a main system operation control section (31) that executes the transmission and reception process when in a first state in which a standby instruction has not been notified from the second terminal corresponding device (4) and stops the transmission and reception process when in a second state in which the standby instruction has been notified from the second terminal corresponding device (4), The second terminal corresponding device (4) performs a communication check to check whether or not the central device (2) and the first terminal corresponding device (3) are connected via the first network (11), and when it is confirmed that the central device (2) and the first terminal corresponding device (3) are connected via the first network (11) and when it is not confirmed that the first terminal corresponding device (3) is connected via the first network (11), it starts the transmission / reception process, and when it is confirmed that the first terminal corresponding device (3) is connected via the first network (11) after starting the transmission / reception process, it is provided with a slave operation control unit (41) that notifies the first terminal corresponding device (3) of the standby instruction. Traffic control system (1).

[0147] <Appendix 2> The traffic control system (1) described in Appendix 1, wherein even if the slave operation control unit (41) cannot confirm that the first terminal corresponding device (3) is connected to the first network after starting the transmission / reception process, if the slave operation control unit (41) can confirm that the first terminal corresponding device (3) is connected to the second network (12), it notifies the first terminal corresponding device (3) of the standby instruction.

[0148] <Appendix 3> a central device (2) for managing traffic on a road network by utilizing a plurality of traffic terminals (6) installed on the road network; a router (5) connected to a traffic terminal (6) installed on the road network via a communication line (10); a first terminal corresponding device (3) and a second terminal corresponding device (4) that are connected to the central device (2) via a first network (11) and to the router (5) via a second network (12) different from the first network (11), and that perform transmission and reception processing for transmitting and receiving data between the central device (2) and the transportation terminal (6) via the router (5); The first terminal corresponding device (3) comprises a main system operation control section (31) that executes the transmission and reception process when in a first state in which a standby instruction has not been notified from the second terminal corresponding device (4) and stops the transmission and reception process when in a second state in which the standby instruction has been notified from the second terminal corresponding device (4), The second terminal corresponding device (4) performs a communication check to check whether or not the router (5) and the first terminal corresponding device (3) are connected via the second network (11), and when it is confirmed that the router (5) and the first terminal corresponding device (3) are connected via the second network (11) and when it is not confirmed that the first terminal corresponding device (3) is connected via the second network (11), it starts the transmission / reception process, and when it is confirmed that the first terminal corresponding device (3) is connected via the second network (12) after the start of the transmission / reception process, it is provided with a slave operation control unit (41) that notifies the first terminal corresponding device (3) of the standby instruction. Traffic control system (1).

[0149] <Appendix 4> The traffic control system (1) described in Appendix 3, wherein the slave operation control unit (41) notifies the first terminal corresponding device (3) of the standby instruction if it can confirm that the first terminal corresponding device (3) is connected to the first network (11) even if it cannot confirm that the first terminal corresponding device (3) is connected to the second network (12) after starting the transmission / reception process.

[0150] <Appendix 5> a central device (2) for managing traffic on a road network by utilizing a plurality of traffic terminals (6) installed on the road network; a router (5) connected to a traffic terminal (6) installed on the road network via a communication line (10); a first terminal corresponding device (3) and a second terminal corresponding device (4) that are connected to the central device via a first network (11) and to the router (5) via a second network (12) different from the first network (11), and that perform transmission and reception processing for transmitting and receiving data between the central device (2) and the transportation terminal (6) via the router (5); The first terminal corresponding device (3) comprises a main system operation control section (31) that executes the transmission and reception process when in a first state in which a standby instruction has not been notified from the second terminal corresponding device (4) and stops the transmission and reception process when in a second state in which the standby instruction has been notified from the second terminal corresponding device (4), The second terminal corresponding device (4) is provided with a slave operation control unit (31) that performs a communication check with each of the central device (2) and the first terminal corresponding device (3) connected via the first network (11), and also performs a communication check with each of the router (5) and the first terminal corresponding device (3) connected via the second network (12), and starts the transmission / reception process when it is confirmed that the second terminal corresponding device (4) is connected to the central device (2) and the router (5) but is not confirmed that it is connected to the first terminal corresponding device (3) via the first network (11) or the second network (12).The second terminal corresponding device (4) is provided with a slave operation control unit (31) that performs a communication check with each of the central device (2) and the router (5) connected via the first network (11) or the second network (12), and Traffic control system (1).

[0151] <Appendix 6> The traffic control system (1) according to any one of Supplementary Notes 1 to 5, wherein the main system operation control unit (31) returns to the first state when a non-standby instruction is input in the second state.

[0152] <Appendix 7> The traffic control system (1) according to any one of appendices 1 to 6, wherein the slave operation control unit (41) notifies the first terminal corresponding device (3) of the standby instruction, and then, when a completion of recovery of the first terminal corresponding device (3) is input, notifies the first terminal corresponding device (3) of the non-standby instruction.

[0153] <Appendix 8> The traffic control system (1) described in Appendix 7, wherein the slave operation control unit (41) notifies the first terminal corresponding device (3) of the standby instruction, and then stops the ongoing transmission / reception process when a completion of recovery of the first terminal corresponding device (3) is input.

[0154] <Appendix 9> The traffic control system (1) according to any one of appendices 1 to 8, wherein the traffic terminal (6) includes a signal control device that controls switching of light color signals of signal lamps installed at intersections. [Explanation of symbols]

[0155] 1. Traffic control system 2…Central device 3...Main terminal compatible device 4... Device compatible with secondary terminals 5. Router 6...Transportation terminal 10...Communication lines 11...Host network 12...Lower network 31...Main control unit 31a...Transmission and reception processing execution unit 31b...Status memory section 32...Host side network connection 33...Lower network connection 41... Slave control unit 41a...Transmission and reception processing execution unit 41b...Status memory unit 41c...State estimation unit 42...Host side network connection section 43...Lower network connection

Claims

1. a central device that manages traffic on the road network by utilizing a plurality of traffic terminals installed on the road network; a router connected to a transportation terminal installed in the road network via a communication line; a first terminal corresponding device and a second terminal corresponding device, which are connected to the central device via a first network and to the router via a second network different from the first network, and which perform transmission and reception processing for transmitting and receiving data between the central device and the transportation terminal via the router; the first terminal corresponding device comprises a main system operation control unit that executes the transmission and reception process when in a first state in which a standby instruction has not been notified from the second terminal corresponding device, and stops the transmission and reception process when in a second state in which the standby instruction has been notified from the second terminal corresponding device; The second terminal corresponding device performs a communication check to check whether or not the central device and the first terminal corresponding device are connected via the first network, and when it is confirmed that the second terminal corresponding device and the central device are connected via the first network but it is not confirmed that the first terminal corresponding device and the first terminal corresponding device are connected via the first network, it starts the transmission and reception process, and when it is confirmed that the first terminal corresponding device and the first terminal corresponding device are connected via the first network by the communication check after starting the transmission and reception process, it is provided with a slave operation control unit that notifies the first terminal corresponding device of the standby instruction. Traffic control system.

2. 2. The traffic control system according to claim 1, wherein the slave operation control unit notifies the first terminal corresponding device of the standby instruction if it can confirm that the first terminal corresponding device is connected to the second network, even if it cannot confirm that the first terminal corresponding device is connected to the first network after starting the transmission / reception process.

3. a central device that manages traffic on the road network by utilizing a plurality of traffic terminals installed on the road network; a router connected to a transportation terminal installed in the road network via a communication line; a first terminal corresponding device and a second terminal corresponding device, which are connected to the central device via a first network and to the router via a second network different from the first network, and which perform transmission and reception processing for transmitting and receiving data between the central device and the transportation terminal via the router; the first terminal corresponding device comprises a main system operation control unit that executes the transmission and reception process when in a first state in which a standby instruction has not been notified from the second terminal corresponding device, and stops the transmission and reception process when in a second state in which the standby instruction has been notified from the second terminal corresponding device; The second terminal corresponding device performs a communication check to check whether or not the router and the first terminal corresponding device are connected via the second network, and when it is confirmed that the router and the first terminal corresponding device are connected via the second network and it is not confirmed that the first terminal corresponding device is connected via the second network, it starts the transmission and reception process, and when it is confirmed that the first terminal corresponding device is connected via the second network by the communication check after starting the transmission and reception process, it is provided with a slave operation control unit that notifies the first terminal corresponding device of the standby instruction. Traffic control system.

4. 4. The traffic control system according to claim 3, wherein the slave operation control unit notifies the first terminal corresponding device of the standby instruction if it can confirm that the first terminal corresponding device is connected to the first network, even if it cannot confirm that the first terminal corresponding device is connected to the second network after starting the transmission / reception process.

5. a central device that manages traffic on the road network by utilizing a plurality of traffic terminals installed on the road network; a router connected to a transportation terminal installed in the road network via a communication line; a first terminal corresponding device and a second terminal corresponding device, which are connected to the central device via a first network and to the router via a second network different from the first network, and which perform transmission and reception processing for transmitting and receiving data between the central device and the transportation terminal via the router; the first terminal corresponding device comprises a main system operation control unit that executes the transmission and reception process when in a first state in which a standby instruction has not been notified from the second terminal corresponding device, and stops the transmission and reception process when in a second state in which the standby instruction has been notified from the second terminal corresponding device; the second terminal corresponding device performs a communication check with each of the central device and the first terminal corresponding device connected by the first network, and also performs a communication check with each of the router and the first terminal corresponding device connected by the second network, and when it is confirmed that it is connected to the central device and the router but is not confirmed that it is connected to the first terminal corresponding device on the first network or the second network, it starts the transmission and reception process, and when it is confirmed by the communication check that it is connected to the first terminal corresponding device on the first network or the second network after starting the transmission and reception process, it notifies the first terminal corresponding device of the standby instruction on the network that it is confirmed to be connected to. Traffic control system.

6. 6. The traffic control system according to claim 1, wherein the main system operation control unit returns to the first state when a non-standby instruction is input in the second state.

7. 7. The traffic control system according to claim 6, wherein the slave operation control unit notifies the first terminal corresponding device of the non-standby instruction when a recovery completion signal is input for the first terminal corresponding device after notifying the first terminal corresponding device of the standby instruction.

8. The traffic control system according to claim 7, wherein the slave operation control unit stops the ongoing transmission / reception processing when a recovery completion signal is input from the first terminal corresponding device after notifying the first terminal corresponding device of the standby instruction.

9. 6. The traffic control system according to claim 1, wherein the traffic terminal includes a signal control device that controls switching of light color signals of signal lamps installed at intersections.

10. a central device that manages traffic on the road network by utilizing a plurality of traffic terminals installed on the road network; a router connected to a transportation terminal installed in the road network via a communication line; A traffic control system comprising a first terminal corresponding device and a second terminal corresponding device, which are connected to the central device via a first network and to the router via a second network different from the first network, and which perform transmission and reception processing for transmitting and receiving data between the central device and the traffic terminal via the router, a main operation control unit of the first terminal corresponding device, when in a first state in which a standby instruction has not been notified from the second terminal corresponding device, executes the transmission / reception process, and when in a second state in which the standby instruction has been notified from the second terminal corresponding device, executes a process of stopping the transmission / reception process; An operation switching method in which a slave operation control unit of the second terminal corresponding device performs a communication check with each of the central device and the first terminal corresponding device to confirm whether they are connected via the first network, and if it is confirmed that the central device and the first terminal corresponding device are connected via the first network but it is not confirmed that the first terminal corresponding device is connected via the first network, it starts the transmission and reception processing, and after starting the transmission and reception processing, if it is confirmed through the communication check that the first terminal corresponding device is connected via the first network, it performs a process to notify the first terminal corresponding device of the standby instruction.

11. a central device that manages traffic on the road network by utilizing a plurality of traffic terminals installed on the road network; a router connected to a transportation terminal installed in the road network via a communication line; A traffic control system comprising a first terminal corresponding device and a second terminal corresponding device, which are connected to the central device via a first network and to the router via a second network different from the first network, and which perform transmission and reception processing for transmitting and receiving data between the central device and the traffic terminal via the router, a main operation control unit of the first terminal corresponding device, when in a first state in which a standby instruction has not been notified from the second terminal corresponding device, executes the transmission / reception process, and when in a second state in which the standby instruction has been notified from the second terminal corresponding device, executes a process of stopping the transmission / reception process; An operation switching method in which a slave operation control unit of the second terminal corresponding device performs a communication check to confirm whether the router and the first terminal corresponding device are connected via the second network, and if it is confirmed that the router and the first terminal corresponding device are connected via the second network but it is not confirmed that the first terminal corresponding device is connected via the second network, it starts the transmission and reception processing, and after starting the transmission and reception processing, when it is confirmed through the communication check that the first terminal corresponding device is connected via the second network, it performs a processing to notify the first terminal corresponding device of the standby instruction.

12. a central device that manages traffic on the road network by utilizing a plurality of traffic terminals installed on the road network; a router connected to a transportation terminal installed in the road network via a communication line; A traffic control system comprising a first terminal corresponding device and a second terminal corresponding device, which are connected to the central device via a first network and to the router via a second network different from the first network, and which perform transmission and reception processing for transmitting and receiving data between the central device and the traffic terminal via the router, a main operation control unit of the first terminal corresponding device, when in a first state in which a standby instruction has not been notified from the second terminal corresponding device, executes the transmission / reception process, and when in a second state in which the standby instruction has been notified from the second terminal corresponding device, executes a process of stopping the transmission / reception process; An operation switching method in which the slave operation control unit of the second terminal corresponding device performs a communication check with each of the central device and the first terminal corresponding device connected via the first network, and also performs a communication check with each of the router and the first terminal corresponding device connected via the second network, and if it can confirm that it is connected to the central device and the router but cannot confirm that it is connected to the first terminal corresponding device on the first network or the second network, it starts the transmission and reception processing, and after starting the transmission and reception processing, when it can confirm that it is connected to the first terminal corresponding device on the first network or the second network through the communication check, it performs a processing to notify the first terminal corresponding device of the standby instruction on the network to which it has been confirmed that it is connected.

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