JP2006215977A - Traffic control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a traffic control system transmitting information of a large capacity without delay, and capable of continuing communication without causing a large transmission delay or further communication trouble even when there is trouble in a communication line. <P>SOLUTION: By properly using a broadband communication line in response to size of data exchanged between terminal devices, trouble such as a transmission delay or communication inability can be prevented. When there is trouble in a certain line of lines L1-L4, a central device sets a detour route in accordance with detour route information stored in a database to continue communication. When there is a plurality of detour route candidates, the central device selects a line with a higher transmission speed. By this, inability of communication due to communication trouble is prevented, and occurrence of new communication trouble can be prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a traffic control system capable of performing communication using a line between a central device installed in a traffic control center and a terminal device installed in a predetermined place.

  In a conventional traffic control system, information is exchanged between a central device installed in a traffic control center and a terminal device (signal controller, vehicle detector, information board, traffic monitoring terminal, etc.). As an example, the traffic monitoring terminal sends moving images and still images to the central device. In another example, the central unit sends information for controlling the lighting timing of the signal lamp to the signal controller.

  The central device and the terminal device are connected by a dedicated line. The dedicated line includes a digital line such as an analog line or ISDN (Integrated Services Digital Network).

  When a temporary communication failure occurs in a dedicated line among a plurality of dedicated lines and the transmission path is interrupted, communication between the terminal apparatus connected to the line and the central apparatus becomes impossible. As a technique for solving such a problem, Japanese Patent Laid-Open No. 2001-23080 (Patent Document 1) describes a transmission path that is blocked by each terminal device performing wireless communication using Internet routing technology. A traffic signal control system and a signal control device capable of bypassing and transmitting information are disclosed.

Japanese Patent Laid-Open No. 2002-2222489 (Patent Document 2) includes a database in which a detour route is registered in a central device or a terminal device, so that the central device or the terminal device can detour when a transmission path is interrupted. A traffic signal control system and a signal controller that set and communicate with a communication path based on a route are disclosed.
JP 2001-23080 A Japanese Patent Laid-Open No. 2002-222489

  When image information is transmitted from a traffic monitoring terminal, if the information is transmitted from the traffic monitoring terminal via a narrow-band line, a large amount of time may be required for transmission processing due to the large amount of image information. In this case, since the traffic control center cannot obtain information at an appropriate timing, there is a possibility that the traffic control cannot be performed appropriately.

  Further, when communication is performed by bypassing a communication line in which a failure has occurred as in the prior art, a communication load may be concentrated on a specific communication line. Since the transmission speed of the dedicated line is low, a new communication failure may occur if the load is concentrated on the line.

  The present invention solves the above-mentioned problems, and its purpose is to transmit a large amount of information without delay, and when a failure occurs in a communication line, a large transmission delay and further communication failure occur. It is to provide a traffic control system capable of continuing communication without causing it to occur.

  In summary, the present invention is a traffic control system, comprising a central device provided in a traffic control center, a traffic terminal device, a broadband line having a transmission speed of 1 Mbps or more, connecting the central device and the traffic terminal device. Is provided.

  Preferably, the broadband line is a DSL (Digital Subscriber Line) line or an optical fiber line.

  More preferably, the traffic terminal device is any one of a signal controller, a vehicle detector, a traffic monitoring terminal, and an information board.

  According to another aspect of the present invention, a traffic control system includes a central device provided in a traffic control center and a plurality of devices that directly transmit or receive predetermined traffic information for traffic control between the central device. The first traffic terminal device.

  When each of the plurality of first traffic terminal devices cannot directly transmit or receive predetermined traffic information with the central device, the route passes through one of the plurality of first traffic terminal devices other than itself. Then, predetermined traffic information is transmitted to or received from the central device.

  The traffic control system further includes a plurality of communication lines connected between each of the plurality of first traffic terminal apparatuses and the central apparatus.

  The plurality of communication lines are classified into a plurality of types according to the transmission speed, and the transmission speed of at least one of the plurality of types of communication lines is 1 Mbps or more.

  Preferably, the traffic control system includes a normal route that is a normal transmission path in communication between each of the plurality of first traffic terminal devices and the central device, and transmission that bypasses the normal route when the normal route is interrupted. A storage device that stores a detour route that is a road is further provided, and each of the central device or the plurality of first traffic terminal devices is scheduled to be stopped on one of the normal routes stored in the storage device In some cases, the scheduled period is stored in advance, and when the current time is within the scheduled period, communication is performed via a detour route obtained by searching the storage device.

  Preferably, the traffic control system includes a normal route that is a normal transmission path in communication between each of the plurality of first traffic terminal devices and the central device, and transmission that bypasses the normal route when the normal route is interrupted. The central device or each of the plurality of first traffic terminal devices confirms the communication state of the normal route at a predetermined interval, and the normal state is abnormal. In some cases, communication is performed by switching to a bypass route obtained by searching the storage device.

  More preferably, each of the central device or the plurality of first traffic terminal devices stores in advance a priority order associated with each of the plurality of communication lines in descending order of transmission speed, and is a detour obtained by searching the storage device When there are a plurality of routes, a bypass route including a communication line with the highest priority is selected.

  Preferably, the traffic control system further includes a plurality of second traffic terminal devices that transmit or receive predetermined traffic information for traffic control with the central device using any one of the plurality of first traffic terminal devices as a relay station. Each of the plurality of second traffic terminal devices, when the predetermined traffic information cannot be transmitted or received between the central device and the relay station, the plurality of first traffic terminals other than the relay station The device is relayed, and predetermined traffic information is transmitted to or received from the central device.

  More preferably, the traffic control system includes a normal route that is a normal transmission path and a normal route when the normal route is interrupted in communication between each of the first and second traffic terminal devices and the central device. And a storage device that stores a bypass route that is a transmission path that bypasses the route, and each of the central device or the plurality of first and second traffic terminal devices is one of the normal routes stored in the storage device. When there is a plan to stop the crab, the scheduled period is stored in advance, and when the current time is within the scheduled period, communication is performed via a detour route obtained by searching the storage device.

  More preferably, the traffic control system includes a normal route that is a normal transmission path and a normal route when the normal route is interrupted in communication between each of the first and second traffic terminal devices and the central device. And a storage device that stores a detour route that is a transmission path that detours the route, and each of the central device or the plurality of first and second traffic terminal devices confirms the communication state in the normal route at a predetermined interval. If the normal state is abnormal, the communication is performed by switching to a bypass route obtained by searching the storage device.

  More preferably, the central device or each of the plurality of first and second traffic terminal devices stores in advance a priority order associated with each of the plurality of communication lines in descending order of transmission speed, and searches the storage device. When there are a plurality of detour routes to be obtained, a detour route including a communication line with the highest priority is selected.

  According to the traffic control system of the present invention, by communicating with a traffic terminal device using a communication line having a transmission rate of 1 Mbps or more, even data such as images can be transmitted without causing a transmission delay. it can.

  In addition, according to the traffic control system of the present invention, when a failure occurs in a line, and there are a plurality of detour routes, a detour route is set by preferentially selecting a line with a high communication speed. New communication failures caused by concentration can be prevented.

  Furthermore, according to the traffic control system of the present invention, since it can be set to communicate via a detour route only for a preset period, when a certain line becomes incapable of communication only for a maintenance period, By switching the communication path from the normal route to the detour route in accordance with the period, communication failure can be prevented.

  Furthermore, according to the traffic control system of the present invention, by using at least two different types of broadband communication lines, even when one type of communication line becomes unable to communicate due to maintenance, other types of communication lines Can be used.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

  FIG. 1 is a diagram showing the entire traffic control system of the present invention.

  Referring to FIG. 1, a traffic control system 100 includes a traffic control center A and a plurality of traffic terminal devices installed at predetermined locations apart from the traffic control center A for traffic control. In FIG. 1, terminal devices 2.1 to 2.4, 3.1 to 3.4 are typically shown as a plurality of traffic terminal devices. The traffic terminal device transmits or receives predetermined traffic information for traffic control. Specifically, the traffic terminal device is a signal controller, a vehicle sensor, an information board, a beacon, a traffic monitoring terminal, or the like.

  The “traffic terminal device” in the present invention refers to a terminal device that is provided at a predetermined location such as an intersection or a roadside and transmits traffic information to and from a central device. Therefore, for example, a personal computer installed in the traffic control center A does not correspond to the traffic terminal device in the present invention. Hereinafter, “traffic terminal device” is simply referred to as “terminal device”.

  The terminal devices 2.1 to 2.4, 3.1 to 3.4 can communicate with each other using radio waves or radio such as light. Therefore, it is not necessary to provide a cable between the terminal devices, and convenience is improved.

  Moreover, the terminal devices 2.1 to 2.4 can communicate with the traffic control center A through the lines L1 to L4, respectively. A specific example of each line will be described. For example, the line L1 is an analog line using an analog dedicated service with a bandwidth item of 3.4 kHz, the line L2 is a DSL line (Digital Subscriber Line), and the line L3 Is an optical fiber line, and the line L4 is a digital line such as ISDN.

  The DSL line used for the line L2 is, for example, ADSL (Asymmetric Digital Subscriber Line), VDSL (Very high bitrate Digital Subscriber Line), or the like. In the following description, it is assumed that the DSL line used in the present invention is an ADSL line.

  In the present invention, a communication line having a transmission rate of 1 Mbps or higher is referred to as a broadband line, and a communication line having a maximum transmission rate of less than 1 Mbps is referred to as a narrowband line. The transmission rates of the lines L1 to L4 are about 9600 bps, 1 to 50 Mbps, 100 Mbps, and 64 kbps, respectively. Therefore, the lines L2 and L3 correspond to broadband lines, and the lines L1 and L4 correspond to narrowband lines.

  In the present invention, since a communication line having a transmission rate corresponding to the size of data transmitted or received by the terminal device is connected, it is possible to prevent failures such as transmission delay and communication failure. Further, when a failure occurs in a certain line among the lines L1 to L4, the central apparatus sets a detour route according to detour route information stored in a database (not shown) and continues communication. When there are a plurality of alternative route candidates, the central unit selects a line having a higher transmission rate. Therefore, it is possible to prevent communication from being impossible due to a line failure and to prevent a new communication failure from occurring.

  The terminal devices 3.1 to 3.4 communicate with the traffic control center A via other terminal devices. In FIG. 1, communication paths (transmission paths) between the terminal devices are simply shown. For example, the terminal device 3.1 communicates with the traffic control center A via the terminal device 2.1 or the terminal device 3.2 and the terminal device 2.2. Whether each of the terminal devices 3.1 to 3.4 communicates with any of the terminal devices 2.1 to 2.4 depends on the size of information transmitted or received by each of the terminal devices 3.1 to 3.4. Depends on. For example, when the terminal device 3.3 is a traffic monitoring terminal, the terminal device 3.3 is sent via the terminal device 2.3 and the line L3 (optical fiber line) in order to send moving image data to the traffic control center A in a short time. Send video data.

  Similarly to the terminal devices 2.1 to 2.4, the terminal devices 3.1 to 3.4 communicate with the traffic control center A via the detour route when the normal communication route is interrupted. To do. For example, the terminal device 3.3 normally communicates with the traffic control center A via the line L3 and the terminal device 2.3. When the line L3 is interrupted, the terminal device 3.3 is connected to the line L2 and the terminal device 2.2. It communicates with the traffic control center A via.

  As described above, the terminal devices 2.1 to 2.4 and the terminal devices 3.1 to 3.4 use any other terminal device other than the terminal device as a relay station, and traffic information with the traffic control center A Can be transmitted via a relay station.

  FIG. 2 is a diagram for explaining the traffic control system 100 of FIG. 1 in a simplified manner.

  Referring to FIG. 2, traffic control center A normally communicates with each of signal controller B, traffic monitoring terminal C, and optical beacon D, which are terminal devices, via lines a, b, and c. Since the traffic monitoring terminal C transmits a large amount of image data, an optical fiber line is used for the line a. Since the traffic information transmitted from the central device to the optical beacon D is information that is not as large as image data but has a relatively large amount of data, an ADSL line is used for the line b. Since the information received from the traffic control center A by the signal controller B is relatively small, an analog line having a low communication cost and relatively stable communication quality is used for the line c. The required transmission bandwidth of the lines a to c varies depending on various conditions. For example, the line a is 1700 bps, the line b is 2600 bps, the line c is 3300 bps (for still images), and 1 Mbps (for moving images). It becomes.

  If the lines b and c are both optical fiber lines, high-speed communication is possible regardless of the data size transmitted and received by the terminal device. However, if the lines used for communication in the system are the same type of line, all lines are subject to maintenance by the line connection provider, making communication impossible in the traffic control system. For this reason, it is necessary for the lines a to c to use two or more types of lines (for example, an optical fiber line, an ADSL line, an analog line, and a digital line as described above) classified according to the transmission speed.

  The optical beacon D performs communication via the line a, the traffic monitoring terminal C, and the line LCD, for example, when communication by ADSL is interrupted. However, if the transmission rate is allowed to be significantly reduced, the optical beacon D may communicate with the line b by an analog modem.

  FIG. 3 is a diagram showing a configuration example of data transmitted in the traffic control system 100 of FIG.

  Referring to FIG. 3, data such as signal control information, image data, and road traffic information using optical beacons is composed of frames in which a necessary number of time-division slot unit data are collected.

  Each slot includes a header part HD and an actual data part DT. The header portion HD further includes a transmission source ID number HD1, a destination ID number HD2, a bypass route ID number HD3, and a bypass flag HD4.

  When the detour flag HD4 of the received data is “1”, the terminal device that has received the data determines that the data is transmitted through the detour route, and sets the detour route ID number HD3 included in the header portion. Data is transmitted to the next terminal device according to the indicated detour route.

  FIG. 4 is a diagram illustrating a configuration example of a detour route database provided in the traffic control system.

  Referring to FIG. 4A, the bypass route database stores a normal route that is a normal communication route and a bypass route that is a route that bypasses the normal route when the normal route is blocked. Entry No. 1 to 5 store a transmission source ID, a destination ID, a detour ID, and a line ID, respectively. The IDs “A” to “D” in the transmission source ID, the destination ID, and the detour ID indicate the traffic control center A, the signal controller B, the traffic monitoring terminal C, and the optical beacon D in FIG. Further, IDs “a” to “c” in the detour ID indicate lines a to c, respectively.

  Entry No. 1 and no. 2, the transmission source ID is “A” and the destination ID is “B”. In other words, entry no. 1 and no. Reference numeral 2 denotes information indicating a communication path when information is transmitted from the traffic control center A to the signal controller B. In this case, the normal route is line c.

  On the other hand, when a failure occurs in the line c, the central device refers to the detour ID. In this case, there are two routes: a route via the traffic monitoring terminal C and a route via the optical beacon D as bypass routes.

  When there are two or more detour routes, the central device refers to the line ID and determines a broader line as a detour route. Line a is an optical fiber line and line b is an ADSL line. Therefore, when a failure occurs in the line c, the line a is preferentially selected. Information indicating the relationship between the line ID and the priority order is stored in a line priority database which is a database different from the detour route database. The detour route database has an item “priority of detour route”. The priority stored in this item is used when it is desired to set a priority different from that of the line priority database.

  In FIG. 4A, entry no. 1-No. For each of 5, the priority of the detour route is “0”. In this case, the priority is determined according to a line priority database described below. When a priority different from the setting in the line priority database is to be set specially, a priority such as “1” or “2” is set in the item “priority of detour route”.

  FIG. 4B is a diagram showing a specific example of a line priority database.

  Referring to FIG. 4B, the line priority database stores a line ID and a priority corresponding to the line ID.

  Entry No. 1, No. 1 2 will be described as an example. Entry No. In 1, the line a is selected when detouring. In the line priority database, the priority of line a is set to “1”. Entry No. In 2, the line b is selected as a bypass route. In the line priority database, the priority of line b is set to “2”. Therefore, when a failure occurs in the line c, the line a having the priority “1” is selected as a detour line.

  The priority is determined by a traffic control center monitor in consideration of the transmission speed of the line and the quality of the line. The priority is determined, for example, based on the stability of the connection using the ease of disconnection after the connection of the line is established as an index. Thus, for example, a first bypass route having a high line transmission speed but low stability after line connection, and a line transmission speed slower than the first bypass route, but the stability after line connection is the first bypass route. When there is a higher second detour route, the priority of the second detour route may be set higher in consideration of the importance of the line.

  The detour route database and the line priority database may be built in the central device or in each terminal device. When a database is built in each terminal device, for example, the traffic control system transmits detour route information and line priority information associated with the addition of the terminal device to each terminal device. Each terminal device adds the received detour route information and line priority information to each database.

  However, it is advantageous that the detour route database and the line priority database are provided in the central apparatus in terms of convenience, such as the addition of the line ID accompanying the addition of the terminal apparatus or the update work accompanying the change of the line type, etc. is reduced. It is. In the following description, it is assumed that the detour route database and the line priority database are provided in the central apparatus.

  FIG. 5 is a flowchart showing a flow of route switching processing by the central apparatus.

  Referring to FIG. 5, the central device constantly monitors whether communication with a terminal device which is a specific communication partner is interrupted (step S1). When the central device determines that communication with the terminal device that is the specific communication partner has been interrupted (No in step S1), it sets an internal line disconnection determination timer and starts measuring a predetermined time (step S2). ).

  When communication from the terminal apparatus is restored within a predetermined time (Yes in step S3), the central apparatus determines that no trouble has occurred in the line and cancels the line disconnection determination timer (step S4).

  When the communication with the terminal device does not return even after the predetermined time has elapsed and the communication remains interrupted (No in step S3 and Yes in step S5), the central device communicates with the terminal device. Determine that the line is faulty. In this case, the central device searches for a bypass route from the bypass route database (step S6).

  If a bypass route is registered in the database (Yes in step S6), the central device sets a communication circuit according to the searched bypass route (step S7). Further, the central device sets a bypass ID number in the header portion of the data to be transmitted according to the bypass route, and sets a bypass flag indicating 1 as a bypass route (step S8). As a result, data is transmitted through a route bypassing the blocked communication line, and communication is restored.

  Note that if the detour route is not registered in the database (No in step S6), communication remains impossible.

  Also, if there is a planned outage such as maintenance by the line connection company, the central unit will go through a detour route using a line that is not planned for the scheduled outage (not subject to maintenance). Communicate.

  FIG. 6 is a flowchart showing route switching processing when there is a planned stoppage.

  Referring to FIG. 6, first, planned stop information is created in step S11. This planned stop information is information such as the date and time when the communication line is stopped, the date and time when the communication line is restored, and the corresponding line. This planned stop information is created, for example, by a traffic control center worker.

  In step S12, planned stop information is input to the central unit. The information input to the central device is a switching line that is an alternative to the line to be stopped, a switching start time, a switching end time, and a temporary detour route that is applied only during the planned stop period.

  Subsequently, in step S13, the central device checks the current time at predetermined intervals, and determines whether or not the switching start time has elapsed. If the current time is after the switching start time (YES in step S13), the central device switches the communication path to the set temporary detour route in step S14, and thereafter communicates along the temporary detour route. To do. On the other hand, if the switching start time has not yet elapsed (NO in step S13), the process returns to step S13 again.

  Subsequently, in step S15, as in step S13, the central device checks the current time every predetermined time to determine whether or not the switching end time has elapsed. If the switching end time has elapsed in step S15 (YES in step S15), the central apparatus returns the communication path to the normal route in step S16. On the other hand, if the switching time has not yet elapsed in step S15 (NO in step S15), the process returns to step S15 again. In this way, the communication path is switched to the detour route for a predetermined period.

  As described above, according to the embodiment of the present invention, data such as images can be transmitted without causing a transmission delay by communicating with a terminal device using a communication line having a transmission rate of 1 Mbps or more. Can be performed.

  Further, according to the embodiment of the present invention, when a failure occurs in a line, when there are a plurality of detour routes, a detour route is set by preferentially selecting a line having a high communication speed, so that the communication load is reduced. New communication failures caused by concentration can be prevented.

  Furthermore, according to the embodiment of the present invention, since it can be set to communicate via a detour route for a preset period, when a certain line becomes incapable of communication only for a maintenance period, By switching the communication path from the normal route to the detour route according to the period, communication failure can be prevented.

  Furthermore, according to the embodiment of the present invention, when at least two different types of wideband communication lines are used, even when one kind of communication line becomes unable to communicate due to maintenance, other kinds of communication lines Can be used.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a figure showing the whole traffic control system of the present invention. FIG. 2 is a diagram for explaining the traffic control system 100 of FIG. 1 in a simplified manner. It is a figure which shows the structural example of the data transmitted in the traffic control system 100 of FIG. It is a figure which shows the structural example of the detour route database provided in a traffic control system. It is a flowchart which shows the flow of the route switching process by a central apparatus. It is a flowchart which shows the route switching process in case there exists a planned stop.

Explanation of symbols

  2.1 to 2.4, 3.1 to 3.4 Terminal device, 100 Traffic control system, A Traffic control center, B Signal controller, C Traffic monitoring terminal, D optical beacon, ac line, DT actual data Part, HD header part, HD1 source ID number, HD2 destination ID number, HD3 bypass route ID number, HD4 bypass flag, L1 to L4, LBC, LBD, LCD line, S1 to S16 steps.

Claims (11)

A central device installed in the traffic control center;
A traffic terminal device that transmits or receives predetermined traffic information for traffic control with the central device;
A traffic control system comprising a broadband line connecting the central device and the traffic terminal device and having a transmission rate of 1 Mbps or more.   The traffic control system according to claim 1, wherein the broadband line is a DSL (Digital Subscriber Line) line or an optical fiber line.   The traffic control system according to claim 2, wherein the traffic terminal device is one of a signal controller, a vehicle sensor, a traffic monitoring terminal, and an information board. A central device installed in the traffic control center;
A plurality of first traffic terminal devices that directly transmit or receive predetermined traffic information for traffic control with the central device;
When each of the plurality of first traffic terminal devices cannot directly transmit or receive the predetermined traffic information with the central device, the plurality of first traffic terminal devices other than itself Send or receive the predetermined traffic information to or from the central device via either
A plurality of communication lines connected between each of the plurality of first traffic terminal devices and the central device;
The plurality of communication lines are classified into a plurality of types according to transmission speed,
The traffic control system, wherein a transmission speed of at least one communication line of the plurality of types is 1 Mbps or more. The traffic control system bypasses the normal route that is a normal transmission path in communication between each of the plurality of first traffic terminal devices and the central device, and the normal route when the normal route is blocked. A storage device that stores a detour route that is a transmission path to be transmitted;
Each of the central device or the plurality of first transportation terminal devices stores a scheduled period in advance when any of the normal routes stored in the storage device is scheduled to stop, and stores the current time 5. The traffic control system according to claim 4, wherein communication is performed via the bypass route obtained by searching the storage device when the time is within the scheduled period. The traffic control system bypasses the normal route that is a normal transmission path in communication between each of the plurality of first traffic terminal devices and the central device, and the normal route when the normal route is blocked. A storage device that stores a detour route that is a transmission path to be transmitted;
Each of the central device or the plurality of first traffic terminal devices checks a communication state in the normal route at a predetermined interval, and searches the storage device when the normal state is abnormal. The traffic control system according to claim 4, wherein communication is performed by switching to the obtained detour route.   Each of the central device or the plurality of first traffic terminal devices is stored in advance in a priority order associated with each of the plurality of communication lines in descending order of transmission speed, and is obtained by searching the storage device. The traffic control system according to claim 6, wherein when there are a plurality of detour routes, a detour route including the communication line with the highest priority is selected. The traffic control system further includes a plurality of second traffic terminal devices that transmit or receive predetermined traffic information for traffic control with the central device using any one of the plurality of first traffic terminal devices as a relay station. Prepared,
When each of the plurality of second traffic terminal apparatuses cannot transmit or receive the predetermined traffic information between the central apparatus and the relay station, the plurality of second traffic terminal apparatuses are any of the plurality of second traffic terminal apparatuses other than the relay station. The traffic control system according to claim 4, wherein the predetermined traffic information is transmitted to or received from the central device by relaying one traffic terminal device. The traffic control system includes a normal route that is a normal transmission path in communication between each of the plurality of first and second traffic terminal devices and the central device, and the normal route when the normal route is interrupted. A storage device that stores a detour route that is a transmission path that detours the route;
Each of the central device or the plurality of first and second traffic terminal devices stores a scheduled period in advance when any of the normal routes stored in the storage device is scheduled to stop. The traffic control system according to claim 8, wherein when the current time is within the scheduled period, communication is performed via the bypass route obtained by searching the storage device. The traffic control system includes a normal route that is a normal transmission path in communication between each of the plurality of first and second traffic terminal devices and the central device, and the normal route when the normal route is interrupted. A storage device that stores a detour route that is a transmission path that detours the route;
Each of the central device or the plurality of first and second traffic terminal devices confirms the communication state in the normal route at a predetermined interval, and if the normal state is abnormal, the storage device The traffic control system according to claim 8, wherein communication is performed by switching to the bypass route obtained by searching.   Each of the central device or the plurality of first and second traffic terminal devices stores in advance a priority order associated with each of the plurality of communication lines in descending order of transmission speed, and searches the storage device. The traffic control system according to claim 10, wherein when there are a plurality of obtained bypass routes, a bypass route including a communication line with the highest priority is selected.

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