Traffic control device

Abstract

To provide a traffic control unit that can appropriately guide a vehicle around a road section in which traffic is regulated.SOLUTION: A traffic control unit has: storage units (12, 13) that store map information representing a plurality of road sections included in a predetermined area, and information representing, of the plurality of road section, a regulation section in which traffic is regulated; a bypass route searching unit 21 that refers to destination information received from a vehicle 4 via a communication network 5 and representing the current location of the vehicle 4 and a destination to determine whether the vehicle 4 is likely to pass through the regulation section, and when the vehicle 4 is likely to pass through the regulation section, searches for, with reference to the map information, a bypass route heading for the destination from the current location without passing through the regulation section; and a notification control unit 22 that notifies the bypass route searched for to the vehicle 4 via the communication network 5 or controls a traffic light 3 located within a predetermined distance from the current location of the vehicle 4 to inhibit approach in a direction toward the regulation section.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a traffic control device. [Background technology]

[0002] Traffic on a road section may be restricted for various reasons, such as road construction or the occurrence of a natural disaster. Therefore, a technology has been proposed that prevents entry into a dangerous area to ensure the safety of road users (see, for example, Patent Document 1). In the technology disclosed in Patent Document 1, when a traffic signal receives natural disaster information, it determines whether or not there is a dangerous area ahead of the traffic signal based on the natural disaster information and dangerous area information pre-registered in the traffic signal. If a dangerous area is detected, the traffic signal display unit displays a red "No Entry" sign, instead of the usual signal display, to prohibit entry into the dangerous area, and also displays an arrow indicating the direction in which entry is permitted. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-120474 Summary of the Invention [Problem to be solved by the invention]

[0004] If entry to a road section where traffic restrictions are in place is uniformly restricted around that road section and vehicles are directed in the same detour direction, there is a risk that vehicles detouring that road section will suffer disadvantages such as congestion or an unnecessarily long detour route.

[0005] Therefore, an object of the present invention is to provide a traffic control device that can appropriately guide vehicles around road sections where traffic is restricted. [Means for solving the problem]

[0006] According to one embodiment, there is provided a traffic control device that includes: a storage unit that stores map information representing a plurality of road sections included in a predetermined area and information representing a restricted section among the plurality of road sections where traffic is restricted; a detour route search unit that refers to destination information representing the current location and destination of the vehicle received from the vehicle via a communication network, determines whether the vehicle is likely to pass through the restricted section, and if the vehicle is likely to pass through the restricted section, searches for a detour route from the current location to the destination without passing through the restricted section by referring to the map information; and a notification control unit that notifies the vehicle of the found detour route via the communication network or controls traffic lights located within a predetermined distance from the current location of the vehicle to prohibit entry into the restricted section. [Effects of the Invention]

[0007] The traffic control device according to the present disclosure has the effect of being able to appropriately guide vehicles around road sections where traffic is restricted. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a traffic control system including a traffic control device. [Figure 2] FIG. 2 is a hardware configuration diagram of a server that is an example of a traffic control device. [Figure 3] FIG. 2 is a functional block diagram of a processor of a server associated with a traffic control device. [Figure 4] FIG. 2 is a diagram illustrating an outline of a traffic control process. [Figure 5] 10 is an operational flowchart of a traffic control process. DETAILED DESCRIPTION OF THE INVENTION

[0009] The traffic control process, as well as the traffic control method and traffic control computer program executed in the traffic control process, are described below with reference to the drawings. The traffic control device determines, for each vehicle, whether it is likely to travel through a road section where traffic is restricted (hereinafter simply referred to as a restricted section) by referring to destination information received from each vehicle and indicating the vehicle's current location and destination. Furthermore, for vehicles determined to be likely to travel through a restricted section, the traffic control device sets a detour route that bypasses the restricted section by referring to the destination information. The traffic control device then notifies each vehicle of the detour route so that the vehicle travels along the set detour route, or controls traffic lights around the vehicle to prohibit entry into the restricted section. This allows the traffic control device to appropriately guide vehicles around the road section where traffic is restricted.

[0010] The road section in this specification may not only refer to a section of a road that is a single road, but may also refer to a section of a road that includes an intersection, or a section of a road that includes a branching road or a merging road.

[0011] FIG. 1 is a schematic diagram of a traffic control system including a traffic control device. In this embodiment, the traffic control system 1 includes a server 2, which is an example of a traffic control device, multiple traffic lights 3, and at least one vehicle 4. Note that FIG. 1 illustrates one traffic light 3 as a representative of the traffic lights 3. Similarly, while FIG. 1 illustrates only one vehicle 4, the traffic control system 1 may include multiple vehicles 4. Each traffic light 3 is installed at a different intersection and is connected to a communication network 5 to which the server 2 is connected via a gateway (not shown) or the like. Therefore, each traffic light 3 can communicate with the server 2 via the communication network 5. Furthermore, the vehicle 4 can wirelessly communicate with multiple wireless base stations 6 connected to the communication network 5. Therefore, the vehicle 4 can communicate with the server 2 via any of the multiple wireless base stations 6 and the communication network 5. Note that FIG. 1 illustrates one wireless base station 6 as a representative.

[0012] The server 2 can change the lighting state of a traffic light 3 to a lighting state designated by the control signal by transmitting a control signal to the traffic light 3 to be controlled among the multiple traffic lights 3 via the communication network 5. That is, the server 2 can enable entry in a specific direction (i.e., turn the lighting state green in a specific direction) or prohibit entry in a specific direction (i.e., turn the lighting state red in a specific direction) for the traffic light 3 to be controlled.

[0013] The vehicle 4 includes, for example, an electronic control unit (not shown), a GPS receiver (not shown), a navigation device (not shown), and a wireless communication device (not shown). The electronic control unit of the vehicle 4 transmits destination information of the vehicle 4 from the wireless communication device to the server 2 via the wireless base station 6 and the communication network 5 at predetermined intervals. The destination information includes, for example, identification information for identifying the vehicle 4, information generated by the navigation device that indicates a planned driving route to the destination of the vehicle 4, and information that indicates the current location of the vehicle 4 measured by the GPS receiver. Alternatively, the destination information may include information that indicates the destination of the vehicle 4 itself instead of the information that indicates the planned driving route. Furthermore, after the vehicle 4 receives detour route information that indicates a detour route from the server 2, the electronic control unit may include the detour route information in the destination information. Furthermore, when the electronic control unit receives the detour route information from the server 2 via the wireless communication device via the communication network 5 and the wireless base station 6, it causes the display device of the navigation device to display the detour route indicated in the detour route information. Alternatively, the electronic control device may automatically control the vehicle 4 so that the vehicle 4 travels along the detour route indicated in the received detour route information.

[0014] Furthermore, a management server 7 for road management is connected to the communication network 5. Therefore, the server 2 can communicate with the management server 7 via the communication network 5. The management server 7 is used to manage traffic conditions for individual road sections within a smart city or connected city, for example, by utilizing advanced technologies such as artificial intelligence (AI) that utilize big data. Therefore, the road sections on which traffic restrictions will be imposed, the reasons for the restrictions, and the dates and times when the restrictions will be imposed are input to the management server 7 via an input device such as a keyboard possessed by the management server 7 or other devices connected to the management server 7. Reasons for the restrictions include, for example, a change in traffic direction for a specific lane, an update to a traffic light system, or road construction. Furthermore, the management server 7 acquires images of any road section generated by one or more cameras installed within the area to be managed. The management server 7 then detects passing vehicles from these images to investigate the traffic volume for each road section within the area to be managed. Therefore, the server 2 can acquire regulation information regarding traffic regulations and traffic information indicating the traffic volume of each road section from the management server 7 via the communication network 5. The regulation information includes information that identifies the road section where the traffic regulation is implemented (for example, a link ID) or information indicating the range of the area where the traffic regulation is implemented, the date and time when the traffic regulation is implemented, and the reason for the traffic regulation.

[0015] 2 is a hardware configuration diagram of a server 2, which is an example of a traffic control device. The server 2 has a communication interface 11, a storage device 12, a memory 13, and a processor 14. The communication interface 11, the storage device 12, and the memory 13 are connected to the processor 14 via signal lines. The server 2 may further have input devices such as a keyboard and a mouse, and a display device such as a liquid crystal display.

[0016] The communication interface 11 is an example of a communication unit, and has an interface circuit for connecting the server 2 to the communication network 5. That is, the communication interface 11 is configured to be able to communicate with each traffic light 3, each vehicle 4, and the management server 7 via the communication network 5. The communication interface 11 passes destination information received from any of the vehicles 4 via the wireless base station 6 and the communication network 5 to the processor 14. The communication interface 11 also passes regulation information and traffic information received from the management server 7 to the processor 14. Furthermore, the communication interface 11 transmits detour route information received from the processor 14 to any of the vehicles 4 via the communication network 5 and the wireless base station 6. Furthermore, the communication interface 11 transmits a control signal received from the processor 14 to any of the traffic lights 3 via the communication network 5.

[0017] The storage device 12 is an example of a storage unit, and includes, for example, a hard disk drive or an optical recording medium and an access device therefor. The storage device 12 stores map information indicating the location and connection relationships of each road included in the area managed by the server 2. Furthermore, the storage device 12 may store a computer program for executing traffic control processing, which is executed on the processor 14.

[0018] The memory 13 is another example of a storage unit and includes, for example, a non-volatile semiconductor memory and a volatile semiconductor memory. The memory 13 stores various information used in the traffic control process, such as destination information received from each vehicle 4, regulation information and traffic information received from the management server 7, identification information and installation positions of each traffic light 3, and map information read from the storage device 12. The memory 13 also temporarily stores various data generated during the execution of the traffic control process.

[0019] Processor 14 is an example of a control unit and includes one or more CPUs (Central Processing Units) and their peripheral circuits. Processor 14 may further include other arithmetic circuits such as a logic unit, a numerical calculation unit, or a graphics processing unit. Processor 14 executes traffic control processing for each restricted section indicated in the traffic control information received from management server 7 during a period corresponding to the date and time when traffic restrictions are imposed in that restricted section.

[0020] 3 is a functional block diagram of processor 14 related to traffic control processing. Processor 14 has a detour route search unit 21 and a notification control unit 22. Each of these units in processor 14 is a functional module realized by, for example, a computer program running on processor 14. Alternatively, each of these units in processor 14 may be a dedicated arithmetic circuit provided in processor 14.

[0021] The detour route searching unit 21 refers to the destination information received from the vehicle 4 and determines whether or not there is a possibility that the vehicle 4 will pass through the restricted section indicated in the traffic regulation information. If there is a possibility that the vehicle 4 will pass through the restricted section, the detour route searching unit 21 refers to map information and destination information and searches for a detour route to the destination of the vehicle 4 without passing through the restricted section. Note that the detour route searching unit 21 may set a detour route only for vehicles 4 whose current location is within a predetermined distance (for example, within several kilometers) from the restricted section. Note that if the traffic regulation information includes information indicating the range of an area where traffic is restricted, the detour route searching unit 21 may identify individual road sections included within the range of the restricted area as restricted sections by referring to the map information.

[0022] For example, if the destination information includes information indicating the planned driving route of vehicle 4, detour route searching unit 21 determines whether or not a restricted section exists on the planned driving route. If a restricted section exists on the planned driving route, detour route searching unit 21 determines that there is a possibility that vehicle 4 will pass through the restricted section. On the other hand, if there is no restricted section on the planned driving route, detour route searching unit 21 determines that there is no possibility that vehicle 4 will pass through the restricted section.

[0023] Furthermore, if the destination information does not include information indicating a planned driving route, the detour route search unit 21 references information indicating the current location and destination of the vehicle 4 included in the destination information and predicts a route to the destination based on the current location. If a restricted section exists on the predicted route, the detour route search unit 21 determines that there is a possibility that the vehicle 4 will pass through the restricted section. In this case, the detour route search unit 21 predicts a route to the destination based on the current location using a predetermined route search method, such as the Dijkstra algorithm. At this time, the detour route search unit 21 may predict multiple routes where the difference in distance or required time from the current location to the destination falls within a predetermined tolerance. Alternatively, the detour route search unit 21 may determine that there is a possibility that the vehicle 4 will pass through the restricted section if the current location of the vehicle 4 is located on a road of a certain standard or higher, the destination is within a predetermined distance from the road of that standard, and a restricted section exists between the current location and a position that is the shortest distance from the destination to the road of that standard.

[0024] The detour route searching unit 21 references the destination and current location of the vehicle 4 indicated in the destination information and map information, and searches for a route from the current location to the destination according to a predetermined route searching method such as Dijkstra's algorithm. In this case, the detour route searching unit 21 searches for the route assuming that restricted sections are impassable. The detour route searching unit 21 then sets, as the detour route, the route that has the shortest distance from the current location of the vehicle 4 to the destination, among the searched routes.

[0025] Alternatively, when searching for a route, the detour route searching unit 21 may use a weighting factor corresponding to the time required to travel through each road section shown in the map information. In this case, the detour route searching unit 21 may search for a route that minimizes the sum of weighting factors from the current location of the vehicle 4 to the destination, i.e., a route that minimizes the time required to travel from the current location of the vehicle 4 to the destination, as a detour route. In this case, the detour route searching unit 21 may calculate the weighting factor for each road section by dividing the length of the road section by the expected speed of the vehicle 4 traveling through that road section. In this case, the detour route searching unit 21 may use the maximum speed set for that road section as the expected speed. Alternatively, the detour route searching unit 21 may refer to traffic information to calculate an average speed for each road section according to the traffic volume, and use this average speed as the expected speed. For this purpose, a reference table or a relational expression representing the relationship between traffic volume and average speed may be stored in advance in the memory 13. The detour route search unit 21 then determines the average speed corresponding to the traffic volume by referring to the reference table or relational expression. In this case, the weighting coefficient is set so that the heavier the traffic volume of a road section, the longer the time required for travel. This makes it easier to set a detour route that avoids road sections with heavy traffic volume. As a result, the detour route search unit 21 can prevent traffic congestion from occurring or worsening in road sections where traffic conditions already exist due to the setting of a detour route.

[0026] Furthermore, the detour route searching unit 21 may refer to the current location and destination indicated in the destination information received from each vehicle 4 to determine whether there are multiple vehicles 4 traveling through the same road section within a certain period (e.g., several tens of seconds to one minute). If there are multiple such vehicles 4, the detour route searching unit 21 may set a different detour route for each vehicle 4. For example, the detour route searching unit 21 compares the detour route set for the vehicle (hereinafter referred to as the leading vehicle) that is closest to the restricted section among multiple vehicles 4 traveling through the road section simultaneously within a certain period with the detour route searched for another vehicle (hereinafter referred to as the following vehicle) following the leading vehicle. The detour route searching unit 21 then determines whether there is an overlapping road section between the detour route set for the leading vehicle and the detour route set for the following vehicle. If there is an overlapping road section, the detour route searching unit 21 searches for another route for the following vehicle that does not pass through the overlapping road section. If the difference between the distance or required time of the previously set detour route and the distance or required time of another route is within a preset allowable range, the detour route search unit 21 sets the other route as the detour route for the following vehicle.

[0027] In this case, the detour route searching unit 21 estimates the distance from the current location to the road section of interest, which is included in the most recent destination information received, for each vehicle 4 that is expected to pass through the road section in the destination information, by referring to the map information. The detour route searching unit 21 then predicts the time at which the vehicle 4 will pass through the road section of interest based on the distance from the current location to the road section of interest and the expected speed of the vehicle 4. The detour route searching unit 21 then determines whether there are multiple vehicles 4 that will pass through the road section of interest within a certain period of time by referring to the expected time at which each vehicle 4 will pass through the road section of interest.

[0028] Note that the detour route searching unit 21 may use a route searching method based on machine learning or deep learning instead of the Dijkstra algorithm as the predetermined route searching method. For example, the detour route searching unit 21 may use a route searching method that uses a so-called neural network as the predetermined route searching method. In this case, map information, the current location and destination of the vehicle 4, and restricted sections as impassable sections are input to the neural network. Furthermore, the traffic volume of each road section indicated in the traffic information may be input to the neural network.

[0029] The detour route search unit 21 notifies the notification control unit 22 of the searched detour route together with the identification information of the corresponding vehicle 4.

[0030] When the notification control unit 22 receives a detour route from the detour route search unit 21, the notification control unit 22 generates detour route information representing the detour route and transmits the generated detour route information to the vehicle 4 identified by the corresponding identification information via the communication interface 11, the communication network 5, and the wireless base station 6. This enables the vehicle 4 to head toward the destination without passing through restricted sections. The detour route information includes, for example, identification information, such as a link ID, that identifies each road section included in the detour route.

[0031] Furthermore, each time the notification control unit 22 receives destination information from the vehicle 4, the notification control unit 22 refers to the current location of the vehicle 4, map information, and the installation positions of each traffic light 3 included in the destination information, and identifies a traffic light 3 at an intersection located within a predetermined distance from the current location. The notification control unit 22 may then control the identified traffic light 3 to prohibit the vehicle 4 from entering the restricted section. In this case, the notification control unit 22 transmits a control signal to the identified traffic light 3 via the communication interface 11 and the communication network 5, causing the light to turn on to allow the vehicle 4 to travel along the detour route and prohibit travel toward the restricted section. In this way, the notification control unit 22 prevents the vehicle 4 from heading toward the restricted section and allows the vehicle 4 to travel along the detour route.

[0032] In addition, for an intersection where multiple vehicles 4 are expected to pass within a certain period of time (for example, several tens of seconds to one minute), if the detour routes for the multiple vehicles 4 are heading in different directions, the notification control unit 22 does not need to transmit a control signal to the traffic light 3 at the intersection. This prevents any vehicle 4 from having difficulty traveling along the detour route set for that vehicle 4. In this case, the notification control unit 22 may determine whether multiple vehicles 4 will travel within a certain period of time at the intersection of interest using a method similar to that used by the detour route search unit 21 to determine whether multiple vehicles 4 will travel within a certain period of time on the road section of interest.

[0033] Regardless of the above, when the vehicle 4 travels toward the restricted section, the notification control unit 22 transmits a control signal prohibiting entry toward the restricted section to the traffic light provided at the last intersection where the vehicle 4 can detour around the restricted section. This prevents the vehicle 4 from mistakenly entering the restricted section.

[0034] FIG. 4 is a diagram illustrating an overview of traffic control processing. In the example shown in FIG. 4, a restricted section 402 exists on a planned travel route 401 of vehicle 4, as indicated by an arrow. Therefore, the detour route search unit 21 sets a detour route 404 for vehicle 4 to travel to destination 403 without passing through restricted section 402. At this time, the detour route 404 is set so as to minimize the distance to destination 403 or the required time. In this example, since setting a detour route to bypass restricted section 402 from intersection 405 closest to restricted section 402 would result in a long detour, the detour route 404 is set so as to deviate from the direction toward restricted section 402 at intersection 406, which is closer to the current location of vehicle 4 than intersection 405. The set detour route 404 is then notified to vehicle 4. Furthermore, the traffic lights 3 provided at intersections 406 and 407 located on the detour route 404 are controlled to prohibit entry toward restricted section 402. That is, these traffic lights 3 are controlled so that the light is red in the direction toward the restricted section 402 and green in the direction along the detour route 404.

[0035] 5 is an operational flowchart of the traffic control process. The processor 14 executes the traffic control process in accordance with the following operational flowchart.

[0036] The detour route searching unit 21 of the processor 14 refers to the destination information received from the vehicle 4 and determines whether or not there is a possibility that the vehicle 4 will pass through the restricted section (step S101). If there is a possibility that the vehicle 4 will pass through the restricted section (step S101-Yes), the detour route searching unit 21 refers to the map information and the destination information received from the vehicle 4 and searches for a detour route to the destination that does not pass through the restricted section (step S102).

[0037] The notification control unit 22 of the processor 14 transmits detour route information indicating the found detour route to the vehicle 4 (step S103). Furthermore, the notification control unit 22 controls each traffic light 3 located within a predetermined distance from the current location of the vehicle 4 to prohibit the vehicle 4 from entering the restricted section (step S104). After step S104, or if there is no possibility that the vehicle 4 will pass through the restricted section in step S101 (step S101-No), the processor 14 ends the traffic control process.

[0038] As described above, this traffic control device sets a detour route that bypasses the restricted section for each vehicle that may be traveling through the restricted section by referring to the vehicle's destination information. The traffic control device then notifies each vehicle of the detour route so that the vehicle travels along the set detour route, or controls traffic lights around the vehicle to prohibit entry into the restricted section. This allows the traffic control device to prevent each vehicle from having to take an unnecessary detour and to prevent congestion caused by all vehicles uniformly taking the same detour route. Therefore, the traffic control device can appropriately guide vehicles around the restricted section.

[0039] According to a modified example, the notification control unit 22 may perform only one of notifying the vehicle 4 of a detour route and controlling each traffic light 3 located around the vehicle 4. This reduces the load on the processor 14 of the server 2 and the communication load on the communication network 5.

[0040] According to another modification, the server 2 itself may have the functions of the management server 7.

[0041] As described above, those skilled in the art can make various modifications to the embodiments within the scope of the present invention. [Explanation of symbols]

[0042] 1 Traffic control system 2 Server (traffic control device) 3. Traffic lights 4 vehicles 5. Communication Network 6. Radio base stations 7 Management Server 11 Communication Interface 12 Storage devices 13. Memory 14 processors 21 Detour route search unit 22 Notification control section

Claims

[Claim 1] a storage unit that stores map information representing a plurality of road sections included in a predetermined area and information representing restricted sections among the plurality of road sections where traffic is restricted; a detour route search unit that, for each of a plurality of vehicles, refers to destination information indicating the current location and destination of the vehicle received from the vehicle via a communication network, determines whether or not the vehicle is likely to pass through the restricted section, and if there is a possibility that the vehicle will pass through the restricted section, searches for a detour route from the current location to the destination without passing through the restricted section by referring to the map information; a notification control unit that, for a vehicle among the plurality of vehicles for which a detour route has been searched, prohibits entry of the vehicle toward the restricted section and allows the vehicle to travel in a direction along the detour route at traffic lights located within a predetermined distance from the current location of the vehicle, the traffic lights being located at intersections where it is expected that other vehicles, for which a detour route different from the detour route of the vehicle, will not pass within a certain period of time including the time when the vehicle passes, and does not execute the restriction control at traffic lights located within the predetermined distance at intersections where it is expected that the vehicle and the other vehicles will pass within the certain period of time and where the detour route of the vehicle and the other vehicles are heading in different directions; A traffic control device having:

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