JP2020098378A - Central device, traffic signal control machine, and traffic signal control system - Google Patents

Abstract

To enable a traffic signal control machine to use signal control parameters equivalent in amount to those of a future period.SOLUTION: This device is a central device for remotely controlling traffic signal control machines installed at a plurality of intersections, and comprises: a control unit that generates first and second control commands for each prescribed control period; and a communication unit that collects both the generated first and second commands for each control period, and transmits the commands to the traffic signal control machines. The first command signal is a signal control command including signal control parameters of a current period amount, and the second control command is a signal control command including signal control parameters of a future period amount.SELECTED DRAWING: Figure 6

Description

The present invention relates to a central device, a traffic signal controller, and a traffic signal control system.

In Non-Patent Document 1, a traffic signal control system has a remote control in which a central device of a traffic control center collectively controls traffic signal controllers at a plurality of intersections, and each traffic signal controller operates independently. It is described that it can be classified into point control.
In remote control, a central unit generates a signal control command including a signal control parameter for each predetermined control cycle, and transmits the generated signal control command to a traffic signal controller.

Patent Document 1 describes that, in a traffic signal control system that employs remote control, traffic signal control that does not disadvantage the user of the navigation system is performed in consideration of future traffic volume that may occur due to route search. ing.

JP, 2011-60019, A

"Revised Traffic Signal Guide", Japan Traffic Engineering Research Society, July 2006, pages 96-98

In the conventional traffic signal control system, the central device that performs remote control is supposed to send only the signal control commands for this cycle to the traffic signal controller one by one. Therefore, even if the central device can calculate the signal control parameters for the future cycle from the predicted value of the inflow traffic, the traffic signal controller cannot use the signal control parameters for the future cycle.
The present invention has been made in view of such conventional problems, and an object thereof is to enable a traffic signal controller to use signal control parameters for future cycles.

(1) An apparatus according to one aspect of the present invention is a central apparatus that remotely controls traffic signal controllers installed at a plurality of intersections, and issues the following first and second control commands at predetermined control cycles. A control unit for generating and a communication unit for transmitting both the generated first and second control commands to the traffic signal controller collectively for each control cycle.
First control command: signal control command including signal control parameters for current cycle Second control command: signal control command including signal control parameters for future cycle

(8) A device according to another aspect of the present invention is a traffic signal controller installed at an intersection that is remotely controlled by a central device, and receives the first and second control commands at predetermined control cycles. When the communication between the communication unit and the central device fails, a control for controlling the signal light color of the intersection by the signal control parameter of the latest signal control command of the received first and second control commands And a section.

(9) A system according to one aspect of the present invention is a traffic signal control system including: a traffic signal controller installed at a plurality of intersections; and a central device that remotely controls the traffic signal controller, The central device collects both the upper control unit that generates the first and second control commands for each predetermined control period and the generated first and second control commands for each control period, and A higher-side communication unit that transmits to a signal controller, the traffic signal controller includes a lower-side communication unit that receives the first and second control commands for each control cycle, and the central device. When a communication failure occurs, a lower-order side control unit that controls the signal light color of the intersection according to the signal control parameter of the latest signal control command of the received first and second control commands.

According to the present invention, traffic signal control can use signal control parameters for future cycles.

It is the whole traffic signal control system lineblock diagram concerning this embodiment. It is a block diagram showing an example of composition of a central unit. It is a block diagram which shows the structural example of a traffic signal controller. It is a flow chart which shows an outline of remote control which a central unit performs. It is a sequence diagram which shows the operation example of the traffic signal controller 4 which receives a signal control command for every control period. It is a sequence diagram which shows another operation example of the traffic signal controller 4 which receives a signal control command for every control cycle Tc. It is a flow chart which shows an example of judgment processing of a control mode.

<Outline of Embodiments of the Present Invention>
Hereinafter, the outline of the embodiments of the present invention will be listed and described.
(1) The central device of the present embodiment is a central device that remotely controls traffic signal controllers installed at a plurality of intersections, and generates the following first and second control commands for each predetermined control cycle. A control unit and a communication unit that collectively transmits both the generated first and second control commands for each control cycle to the traffic signal controller.
First control command: signal control command including signal control parameters for current cycle Second control command: signal control command including signal control parameters for future cycle

According to the central device of the present embodiment, the control unit collectively transmits both the generated first and second control commands for each control cycle to the traffic signal controller, so that the traffic signal control is performed in the current cycle. In addition to the signal control parameters for minutes, the signal control parameters for future cycles can be used.

(2) In the central device of the present embodiment, the first control command includes time information indicating a scheduled start time of the signal control parameter to be executed by the traffic signal controller in the current cycle, and the second control command includes the second information. It is preferable that the control command includes time information indicating a scheduled start time of the signal control parameter to be executed by the traffic signal controller in the future cycle.
With this configuration, the traffic signal controller can determine the switching timing of the signal control parameter based on the time information included in the first and second signal control commands.

(3) In the central device of the present embodiment, the second control command includes at least one of the signal control commands including the signal control parameter based on the predicted value of the traffic flow data of the intersection as original data. It is preferable.
By doing so, it is possible to notify the traffic signal controller in advance of signal control parameters (for example, parameters for sensitivity control) that use the predicted value of the traffic flow data as the original data, so that the traffic signal controller can be controlled. It can be executed more reliably.

(4) In the central device of the present embodiment, it is preferable that the second control command includes at least one of the signal control commands including the signal control parameter whose future implementation has been determined.
In this way, it is possible to notify the traffic signal controller in advance of signal control parameters (for example, parameters for time control or flash control) whose future implementation has been decided, so It is possible to surely execute flash control and the like.

(5) In the central device of the present embodiment, the control cycle is Tc, the future period after the start time of the current cycle is Tf, the quotient obtained by dividing the future period by the control cycle is M, and the intersection When the cycle length is C, it is preferable that the relational expression of Tf=M×Tc≧C is satisfied.
The reason is that in the case of a traffic signal controller that follows the current signal control parameters for at least one cycle, it provides the signal control parameters to be implemented in the future period Tf (=M×Tc) shorter than the cycle length C. However, this is because the traffic signal controller does not adopt the provided signal control parameters.

(6) In the central device of the present embodiment, the control cycle is Tc, the future period after the start time of the current cycle is Tf, the quotient obtained by dividing the future period by the control cycle is M, and the intersection When the cycle length is C and the sensitive fluctuation width at the intersection is Tk, it is preferable that the relational expression of Tf=M×Tc≧C+Tk is satisfied.
The reason is that the traffic signal controller executing the terminal sensitive control provides the traffic signal control parameter provided with the traffic signal control parameter even if the traffic signal controller has a future period Tf (=M×Tc) shorter than C+Tk. This is because the machine does not adopt it.

(7) In the central device of the present embodiment, the control cycle is Tc, the future period after the start time of the current cycle is Tf, the quotient obtained by dividing the future period by the control cycle is M, and the cycle of the intersection When the length is C and the offset tracking width at the intersection is To, it is preferable that the relational expression of Tf=M×Tc≧C+To holds.
The reason is that, even if the traffic signal controller that is performing the system control provides the signal control parameter of the future period Tf (=M×Tc) shorter than C+To, the traffic signal controller does not provide the provided signal control parameter. Is not adopted.

(8) The traffic signal controller of this embodiment is a traffic signal controller installed at an intersection that is remotely controlled by a central device, and receives the following first and second control commands at predetermined control cycles. When a failure occurs in the communication between the communication unit and the central device, the signal light color of the intersection is controlled by the signal control parameter of the latest signal control command of the received first and second control commands. And a control unit.
First control command: signal control command including signal control parameters for current cycle Second control command: signal control command including signal control parameters for future cycle

According to the traffic signal controller of the present embodiment, the control unit uses the signal control parameter of the latest signal control command of the received first and second control commands when the communication with the central device fails. , Control the traffic light color at the intersection.
Therefore, even if a communication failure with the central apparatus occurs, the signal light color at the intersection can be controlled by the appropriate signal control parameter notified in advance from the central apparatus before the communication failure occurs.

(9) The traffic signal control system of this embodiment is a traffic signal control system including the traffic signal controller of this embodiment and the central device of this embodiment.
Therefore, the traffic signal control system of this embodiment has the same effects as the traffic signal controller and the central unit of this embodiment.

<Details of the embodiment of the present invention>
Hereinafter, details of an embodiment of the present invention will be described with reference to the drawings. Note that at least a part of the embodiments described below may be arbitrarily combined.

〔Definition of terms〕
In describing the details of the present embodiment, first, terms used in this specification will be defined.
"Vehicle": Refers to all vehicles that travel on the road. Therefore, in addition to automobiles, light vehicles and trolleybuses, motorcycles also correspond to vehicles.
In the present embodiment, the term “vehicle” simply includes both a probe vehicle having an in-vehicle communication device capable of transmitting probe information and a normal vehicle not having the in-vehicle communication device.

"Probe information": Refers to various information regarding the vehicle sensed by the probe vehicle running on the road.
The probe information is also called probe data or floating car data. The probe information can include various vehicle data such as identification information of the probe vehicle, vehicle position, vehicle speed, vehicle azimuth, and their generation time. As the probe information, information such as position and acceleration acquired by a smartphone or tablet PC in the vehicle may be used.

“Probe vehicle”: A vehicle that senses probe information and sends it to the outside. Vehicles passing on the road include both probe vehicles and vehicles other than these.
However, even a vehicle that does not have a dedicated vehicle-mounted communication device that transmits probe information, but a vehicle that has a mobile terminal such as a smartphone or a tablet PC that can transmit the current position, etc., is also included in the probe vehicle.

“Signal control parameter”: The cycle length, split, and offset, which are the temporal elements of signal display, are collectively referred to as the signal control parameter. Also called a signal control constant.
"Cycle length": The time of one cycle from the blue (or red) start time of a traffic light to the next blue (or red) start time.

“Split”: refers to the ratio of the length of time allocated to each presentation to the cycle length. Generally expressed as a percentage or percentage. Strictly speaking, it is the effective green time divided by the cycle length.
"Offset": In system control or regional control, a time point at which a signal is displayed, for example, a start time point of a main road green light signal from a reference time point common to the traffic signal group, or a same display start point between adjacent intersections. I mean. The former is called an absolute offset and the latter is called a relative offset, which is expressed as a percentage of time (seconds) or cycles.

“Queue”: A queue of vehicles stopped before the intersection due to waiting for a red light.
"Traffic volume": The number of vehicles passing through in a unit time. Unless otherwise specified, the number of vehicles passing for one hour is used, but for control and evaluation, a short-term traffic volume such as seconds, 5 minutes, or 15 minutes may be used. Generally, the traffic volume increases according to the traffic demand, but decreases when the traffic demand exceeds the traffic capacity.

"Load rate": In the supersaturated state, it is necessary to consider "load traffic volume" which is the traffic volume passing through the stop line plus the number of remaining queues as the controlled variable.
The ratio of the load traffic volume (traffic flow rate) per unit time to the saturated traffic flow rate is called the load rate. The load factor is equivalent to the demand factor when the remaining number of unsaturated vehicles is small.
"Traffic demand": The amount of traffic or the traffic flow rate that arrives at the stop line of the inflow route within a certain period of time is called traffic demand, for each intersection or inflow route, or for each traffic route.

"Traffic flow rate": The value obtained by converting the number of vehicles passing through a section of a lane or a roadway at a certain time (usually less than 1 hour) per unit time (usually 1 hour) is called the traffic flow rate.
For example, when the traffic volume for 15 minutes is 90 vehicles, the traffic flow rate for this 15 minutes is 360 (vehicles/hour) or 6 (vehicles/minute). The traffic flow rate is the reciprocal of the average headway time of vehicles passing through a certain period of time.

"Saturated traffic flow rate": The saturated traffic flow rate is the maximum number of vehicles that can pass the stop line per lane at a unit time (for example, 1 second) at the inflow section of an intersection with sufficient traffic demand. Say.
If there is a right-turn lane or a left-turn lane other than a straight lane and the traffic flow lines are different, the saturated traffic flow rate value will be different. The value of the saturated traffic flow rate also varies depending on the road or traffic conditions such as the lane width and the mixture ratio of large vehicles.

“Point control”: When traffic signal control is classified according to the number of intersections and the spatial configuration, it can be classified into three types: point control, system control, and plane control. Among these, the point control is a method of independently controlling the traffic light at the intersection. Also called independent control.

"System control": A method of controlling a series of adjacent intersections by interlocking with each other. The feature of this method is that a common cycle length (common cycle length of the system) and an offset are determined for a plurality of signals for system control.
"Surface control": A method to collectively control a large number of traffic lights installed on a road network that spreads in a plane. It is an area-wide expansion of line system control.

"Traffic adaptation control": The central equipment of the traffic control center changes the traffic signal control parameters for the traffic signal controllers at important intersections or the traffic signal controllers at multiple intersections that are system-controlled or plane-controlled. It is a control method.
Since the traffic adaptation control enables sophisticated system control corresponding to the fluctuation of traffic flow, it is applied to roads that require large traffic processing efficiency due to large fluctuations in traffic volume and time.

Traffic adaptation control is classified into two types, "program selection control" and "program formation control". The program selection control is a method of selecting, from a plurality of combinations (programs) prepared in advance, one suitable for the current traffic situation from the information of the vehicle detectors.
Program formation control is a method that does not prepare a combination of a limited number of signal control parameters, and based on the information of the vehicle detector and the like, immediately determines the switching timing of the signal control parameters or the signal light color,

"MODERATO" (Management by Origin-DEstination Related Adaptation for Traffic Optimization): The name of program formation control in UTMS (Universal Traffic Management System) in Japan.
MORERATO is a system that automatically generates signal control parameters from the load factor (= (inflow traffic volume+number of queues)/saturated traffic flow rate) for each inflow route at an intersection.

“SCOT” (Split Cycle Offset Optimization Technique): A program formation control method developed in the United Kingdom. It is widely adopted, especially in European countries.
SCOOT is a system that uses data from vehicle detectors installed on roads to automatically adjust the traffic light color of traffic signals so as to adapt to current traffic conditions in near real time.

[Overall system configuration]
FIG. 1 is an overall configuration diagram of a traffic signal control system 1 according to this embodiment.
As shown in FIG. 1, the traffic signal control system 1 of the present embodiment includes a plurality of signal lamps 2, a plurality of traffic signal controllers 4, a central device 6, a roadside sensor 8, a roadside communication device 10, and the like.

The central device 6 is installed in, for example, a traffic control center. The signal lights 2 and the traffic signal controller 4 are installed at a plurality of intersections Ji (i=1 to 12) included in the area covered by the traffic control center.
In FIG. 1, for simplification of the drawing, only one signal lamp 2 corresponding to each intersection Ji is shown. However, at the actual intersection Ji, four signal lights 2 are installed to display the presence or absence of the right of passage for each vehicle 5 traveling in the up and down directions on the intersection road.

The central device 6 and the traffic signal controller 4 have the function of a communication terminal that complies with the communication standard of the mobile communication system. The mobile communication system is, for example, LTE (Long Term Evolution) or fifth generation mobile communication system (5G).
Therefore, the central device 6 and the plurality of traffic signal controllers 4 in the jurisdiction area can mutually transmit and receive predetermined information by wireless communication via a wireless base station (not shown).

The central unit 6 can execute remote control (for example, MODERATO) on the traffic signal controller 4. The traffic signal controller 4 is, for example, a U-shaped traffic signal controller.
Therefore, the central device 6 can execute system control for the traffic signal controllers 4 belonging to the jurisdiction area, which is control for intersections on the same section, or plane control in which the system control is extended to the road network. ..

Specifically, the central device 6 generates a signal control parameter using the sensing data obtained from the roadside sensor 8 and the roadside communication device 10 as original data. The central unit 6 transmits a signal control command including the generated signal control parameter to the traffic signal controller 4.
The traffic signal controller 4 switches the lighting color of the signal lamp 2 according to the signal control parameter included in the received signal control command. The remote control by the central unit 6 may be a control method other than MODERATO (for example, SCOOT).

The roadside sensor 8 is, for example, a vehicle detector that senses the vehicle 5 traveling immediately below with ultrasonic waves, a loop coil that senses the vehicle 5 by a change in inductance, or an image type sensor that senses the vehicle 5 from a captured image of a camera. It consists of vehicle detectors.
The roadside sensor 8 is connected to the traffic signal controller 4 installed at the corresponding intersection Ji via a wired or wireless communication line.

The roadside sensor 8 transmits sensing data (for example, sensing pulse signal) regarding the vehicle 5 to the traffic signal controller 4. The sensing data is used by the traffic signal controller 4 for the terminal sensitive control of the intersection Ji and is also transferred to the central device 6 by the traffic signal controller 4.

The roadside communication device 10 is a wireless communication device that wirelessly transmits and receives various types of information to and from an in-vehicle communication device (may be a mobile terminal). The roadside communication device 10 includes, for example, a wireless LAN compatible communication device, an optical beacon, or a radio wave beacon.
The roadside communication device 10 is connected to the traffic signal controller 4 installed at the corresponding intersection Ji via a wired or wireless communication line.

The roadside communication device 10 transfers the probe information received from the vehicle 5 to the traffic signal controller 4. The traffic signal controller 4 transfers the received probe information to the central device 6.
The traffic signal controller 4 transfers the vehicle-provided information (for example, traffic jam information) received from the central device 6 to the roadside communication device 10. The roadside communication device 10 transfers the received vehicle-provided information to the vehicle-mounted communication device.

[Configuration of central device]
FIG. 2 is a block diagram showing a configuration example of the central device 6.
As shown in FIG. 2, the central device 6 of this embodiment includes a control unit 61, a display unit 62, a communication unit 63, a storage unit 64, and an operation unit 65.
The control unit 61 is connected to the display unit 62, the communication unit 63, the storage unit 64, and the operation unit 65 via the internal bus. The control unit 61 controls the operation of each of these hardware units.

The control unit 61 is composed of an arithmetic processing unit including a CPU (Central Processing Unit). The control unit 61 reads the computer program 66 stored in the non-volatile memory of the storage unit 64 and performs various information processing according to the program 66.
The storage unit 64 is a storage device including at least one nonvolatile memory of a HDD (Hard Disk Drive) and an SSD (Solid State Drive) and a volatile memory such as a random access memory.

The communication unit 63 includes a communication interface of a mobile communication system.
The communication unit 63 receives from the traffic signal controller 4 sensing data of the roadside sensor 8, probe information acquired by the roadside communication device 10 from the vehicle 5, and the like.
The communication unit 63 transmits a signal control command including signal control parameters, provision information for vehicles, and the like to the traffic signal controller 4.

The computer program 66 stored in the storage unit 64 includes an OS (Operating System) and a program for communication control for the communication unit 63, as well as four control methods (human intervention, time control, sensitive control, and A program for causing the control unit 61 to execute (backup control) is included.

The control unit 61 calculates a traffic index (such as the inflow traffic volume and the number of queues) for each inflow route from the detection data of the roadside sensor 8 and the probe information acquired by the roadside communication device 10 from the vehicle 5.
The control unit 61 generates a signal control parameter to be applied to a predetermined traffic signal controller 4 based on the calculated traffic index. The control unit 61 causes the communication unit 63 to transmit a signal control command addressed to the traffic signal controller 4 including the generated signal control parameter.

The display unit 62 is a display that displays predetermined information. The display unit 62 displays a road map of the jurisdiction area, positions of all the signal lights 2 and the traffic signal controller 4 on the road map, traffic information such as a traffic jam section, and an operation state of the traffic signal controller 4. To display.
The operation unit 65 includes input devices such as a keyboard and a mouse. The operator of the traffic control center can give a necessary command to the control unit 61 of the central unit 6 through the operation unit 65.

[Control system of central device]
The remote control control method executed by the control unit 61 of the central apparatus includes four types of "human intervention", "time control", "sensitive control" and "backup control".
The execution order of the four control methods is human intervention>time control>sensitive control>backup control. Therefore, the control unit 61 of the central device 6 switches the control method to the time control when a predetermined time period is reached during execution of the sensitive control.

"Human intervention": This is a control method for forcibly operating the traffic signal controller according to the signal control parameters that the operator of the traffic control center inputs.
Specifically, it is a control method in which a man-machine device of a traffic control center transmits a signal control command including signal control parameters to a traffic signal controller and operates the traffic signal controller according to the signal control parameters. Human intervention is often performed when a cycle or split is forcibly changed when an event or a peculiar event such as a traffic accident occurs.

"Time control": a control method in which a traffic signal controller is operated with a signal control parameter specified in advance in a specified time zone.
Specifically, in the time control, a predetermined time zone and a signal control parameter are registered in the central device 6, and the central device 6 sends a signal control command including the signal control parameter registered in the registered time zone. It transmits to the traffic signal controller 4. The time of day control is often executed when the cycle is intentionally lengthened during the hours when the traffic volume increases in the morning and evening.

“Sensitive control”: The above-mentioned traffic adaptive control (for example, MODERATO). In the sensitive control, the central unit 6 automatically generates signal control parameters or selects patterns using traffic flow data such as inflow traffic volume, and performs subarea coupling and system control.
“Backup control”: a control method that operates the traffic signal controller 4 based on preset signal control parameters, past control history, and the like when the sensitive control cannot be performed due to a failure of the vehicle detector.

[Structure of traffic signal controller]
FIG. 3 is a block diagram showing a configuration example of the traffic signal controller 4.
As shown in FIG. 3, the traffic signal controller 4 of the present embodiment includes a control unit 41, a lamp driving unit 42, a communication unit 43, a storage unit 44, and the like.
The control unit 41 is connected to the lamp drive unit 42, the communication unit 43, and the storage unit 44 via an internal bus. The control unit 41 controls the operation of each of these hardware units.

The control unit 41 is composed of an arithmetic processing unit including a CPU. The control unit 41 reads the computer program 45 stored in the non-volatile memory of the storage unit 44 and performs various information processing according to the program 45.
The storage unit 44 is a storage device including at least one non-volatile memory (recording medium) of the HDD and the SSD and a volatile memory (recording medium) including a random access memory or the like.

The communication unit 43 includes a communication interface of a mobile communication system. The communication unit 43 also includes a communication interface with the roadside sensor 8 and the roadside communication device 10.
The communication unit 43 transfers the sensing data of the roadside sensor 8 and the probe information received from the roadside communication device 10 to the central device 6. The communication unit 43 transfers the vehicle-provided information received from the central device 6 to the roadside communication device 10.

The computer program 45 stored in the storage unit 44 includes an OS, a program for controlling communication with the communication unit 43, and a program for causing the control unit 41 to execute the four control modes described below.

Based on the signal control parameter received from the central device 6 or the signal control parameter preset in the device itself, the control unit 41 switches ON/OFF switching timing for each signal light in one cycle (hereinafter, “light color switching”). Timing.)).
The control unit 41 outputs a switching signal to the lamp drive unit 42 at the light color switching timing when the local time of the own device is determined.

The lamp drive unit 42 includes a semiconductor relay (not shown). The semiconductor relay of the lamp drive unit 42 turns on or off the electric power for each signal lamp of the signal lamp 2 according to the switching signal input from the control unit 41.

[Control mode of traffic signal controller]
The control modes executed by the control unit 41 of the traffic signal controller 4, which is the control target of the remote control by the central unit 6, are 4 types of "central control", "continuation control", "independent control" and "flash control". Types are included.

"Centralized control": This is a control mode in which the signal lamp color of the signal lamp device 2 is switched according to the signal control parameter included in the latest signal control command received from the central device 6 during one cycle.
"Continuous control": a control mode in which the signal lamp color is switched according to the signal control parameter executed in the previous cycle when a new signal control command is not received from the central unit 6 during one cycle.

"Independent control": This is an alternative control mode that is performed when a new signal control command is not received from the central unit 6 even if one cycle elapses after shifting to the continuous control. The alternative control is, for example, multi-step control for switching the signal lamp color in a preset number of step seconds.
"Flash control": This is a control mode in which the yellow traffic light on the main road is flashed and the red traffic light on the slave road is flashed.

[Outline of traffic adaptation control]
FIG. 4 is a flowchart showing an outline of traffic adaptation control (sensitivity control) executed by the central device 6.
As shown in FIG. 4, in the information processing of the traffic adaptation control by the central device 6, "traffic flow measurement" (step S1), "traffic index calculation" (step S2), "signal control parameter calculation" ( Step S3) and “transmission of signal control command” (step S4) are included.

The control unit 61 of the central apparatus 6 repeatedly executes the processes of steps S1 to S4 at every predetermined control cycle Tc (for example, 1 minute, 2.5 minutes, or 5 minutes). In this embodiment, the control cycle Tc of the traffic adaptation control is 1 minute.

The traffic flow measurement (step S1) is a process of measuring the traffic flow for each inflow path of the intersection Ji for each control cycle Tc. Specifically, it is a process of obtaining traffic flow data used to calculate a traffic index based on sensing data obtained from the roadside sensor 8 and the roadside communication device 10.
The traffic flow data includes the inflow traffic volume at the intersection Ji, the number of queues, and the saturated traffic flow rate. The saturated traffic flow rate may be a set value based on the road structure.

The calculation of the traffic index (step S2) is a process of calculating the traffic index of the previous cycle for each control cycle Tc using the traffic flow data of the previous cycle obtained in step S1.
For example, the traffic index used in MODERATO is the load factor ρij for each inflow direction j (j=1, 2) of the current i (i=1, 2). The load factor ρij is the ratio of the traffic demand to the maximum traffic volume that can be processed in one cycle, and is expressed by the following equation (1).

ρij=(Qij+k×Eij)/Sij (1)
However, Qij: Traffic flow into the intersection (vehicles/second)
k: weighting factor (for example, 1.0)
Eij: Traffic equivalent value of the number of queues (vehicles/second)
Sij: Saturated traffic flow rate (vehicle/second)

The signal control parameters are calculated (step S3) by using the traffic index for the previous cycle calculated in step S2 to calculate the signal control parameters for the current cycle such as the split of the intersection Ji and the cycle length for each control cycle Tc. It is a process to do. For example, the plit λi of the presentation i is calculated by the following equation (2).
ρi=Max(ρi1, ρi2)
λi=ρi/Σρi (2)

Further, the cycle length C of the important intersection is calculated by the following equation (3).
C=(a1×L+a2)/(1-a3×Σρi) (3)
However, L: Lost time (seconds)
a1 to a3: coefficients

The signal control command is transmitted (step S4) by generating a signal control command including the signal control parameters for the current cycle calculated in step S3 for each control cycle Tc, and generating the signal control command for the current cycle at the intersection Ji. This is a process of transmitting to the traffic signal controller 4.
The control unit 61 of the central device 6 can calculate the following two types of traffic flow data in step S1. In FIG. 4, “m” is the number of times the control cycle Tc progresses, where m=0 is the current time, m=−1 is the previous time, and m≧1 is the future number of times of the future.

Traffic flow data for the previous cycle (m=-1): Past traffic flow that occurred in the control cycle Tc of the previous cycle (m=-1), which is the original data of the signal control parameter for the current cycle (m=0) It is data.
Intersection data after the current cycle (m=0, 1...): One time before each future cycle (m) that is the original data of the signal control parameter for the future cycle after the next time (m=1, 2...). =0, 1...) Future traffic flow data that may occur in the control cycle Tc.

As shown in FIG. 4, here, the start time te of the signal control parameter of the current cycle (m=0) is 09:03, and the future period Tf (>Tc) after the start time (=te) is 5 minutes. .. Therefore, if the quotient obtained by dividing the future period Tf by the control cycle Tc is M, the future period Tf=M×Tc=5×1=5 minutes.

Various methods are conceivable for predicting traffic flow data after the current cycle (m=0, 1,...) Used for calculating signal control parameters for future cycles (m=1, 2...) The following prediction methods 1 and 2 can be adopted.
Prediction method 1: When the route information that the vehicle 5 travels in the future is included in the probe information, the inflow traffic volume after the current cycle of the intersection Ji is predicted based on the route information.
Prediction Method 2: Statistical accumulation of fluctuation patterns of inflow traffic volume, and inflow traffic volume in similar time zones on similar days in the past are set as inflow traffic volume at the intersection Ji after this cycle.

When the control unit 61 of the central apparatus 6 calculates the traffic flow data after the current cycle (m=0, 1...) In step S1, it calculates the traffic flow data after the current cycle (m=0, 1...) In step S2. ) Are calculated, and the signal control parameters for the next cycle (m=1, 2...) Are calculated in step S3.

As described in step S4-1 (conventional transmission method) of FIG. 4, in the U-type communication application standard of the U-type traffic signal controller, the central unit 6 sends only the signal control command for the current cycle (m=0). It is supposed to transmit to the traffic signal controller 4 one by one.
In this case, the control unit 61 of the central unit 6 only calculates the signal control command for the current cycle (m=0) even if the signal control parameters for the future cycle (m=1, 2...) Are calculated in step S3. Is transmitted to the traffic signal controller 4 several seconds before the start time te of the current cycle.

As described in step S4-2 (transmission method of this embodiment) in FIG. 4, it is possible to collectively transmit a plurality of signal control commands for the current cycle and future cycles.
In this case, the control unit 61 of the central apparatus 6 calculates the signal control parameters for the future cycle (m=1, 2...) In step S3, and calculates the current cycle (m=0) and the future cycle. Both signal control commands (m=1, 2...) Are transmitted to the traffic signal controller 4 several seconds before the start time te of the current cycle.

When the control unit 61 of the central device 6 collectively transmits the signal control command for the current period (m=0) and the signal control command for the future period (m=1, 2...), each signal control is performed. Time information (09:03, 09:04, 09:05...) Is included in each command.
Specifically, the signal control command for the current cycle (m=0) includes the scheduled start time of the signal control parameter to be executed by the traffic signal controller 4 in the current cycle (for example, the start time te=09 of the current cycle: 03) is written.

In the signal control command for the future cycle (m=1, 2...), the scheduled start time of the signal control parameter to be executed by the traffic signal controller 4 in each future cycle (for example, the start time of each future cycle (09: 04,09:05...)) is written.
However, the scheduled start time of the signal control parameter to be executed by the traffic signal controller 4 is not necessarily limited to the start time of the control cycle Tc, and may be any time point (for example, human intervention) within the control cycle Tc. Or the start time of time control).

The table of signal control commands in FIG. 4 exemplifies the signal control commands generated when the current cycle is m=0. However, the control unit 61 of the central device 6 controls the control cycle Tc every m times. Then, the same processing as above is performed.
That is, when the current cycle is m=1, the control unit 61 of the central apparatus 6 generates the signal control command for the future period Tf for 5 cycles of m=2 to 6, and the current cycle is m=2. In this case, the signal control command for the future period Tf for 5 cycles of m=3 to 7 is generated. The same applies after m=3.

Therefore, for example, the signal control parameter for 09:05 calculated in the control cycle Tc of m=0 (hereinafter referred to as “old parameter”) and the signal for 09:05 calculated in the control cycle Tc of m=1. When the value of the control parameter (hereinafter, referred to as “new parameter”) is different, the control unit 61 of the central device 6 updates the signal control parameter included in the signal control command of 09:05 to the new parameter.

[Operation example of traffic signal controller]
FIG. 5 is a sequence diagram showing an operation example of the traffic signal controller 4 that receives a signal control command at each control cycle Tc.
In FIG. 5, transmission data n (n=1 to 6) means data transmitted by the central device 6 at each control cycle Tc. In the conventional transmission method (step S4-1 in FIG. 4 ), the central device 6 includes only the signal control command for the current cycle (09:03) in the transmission data 1.

As shown in FIG. 5, it is assumed that the traffic signal controller 4 does not receive the transmission data 2 due to communication failure, for example.
In this case, when the control unit 41 of the traffic signal controller 4 executes the centralized control by the signal control command for the current cycle (09:03) of the transmission data 1, the continuous control is executed for the next one cycle. Then, the control unit 41 executes the independent control from the next cycle after the end of the continuous control.

As described above, in the method in which only the signal control commands for the current cycle (09:03) are transmitted one by one, the central device 6 can calculate the signal control parameters for the future cycle (09:04 or later). However, the traffic signal controller 4 cannot use the signal control parameters for future cycles.
Therefore, when the traffic signal controller 4 cannot receive the signal control command due to communication failure or the like, the traffic signal controller 4 shifts to the continuous control and the independent control earlier, and the traffic adaptation control based on future traffic flow data is performed. There is a problem that it cannot operate properly.

[Another operation example of traffic signal controller]
FIG. 6 is a sequence diagram showing another operation example of the traffic signal controller 4 that receives a signal control command at each control cycle Tc.
In FIG. 6, transmission data n (n=1 to 6) means data transmitted by the central device 6 in each control cycle Tc. In the transmission method of this embodiment (step S4-2 in FIG. 4 ), the central device 6 includes the signal control commands for the current cycle (09:03) and the future cycle (09:04 or later) in the transmission data 1. ..

As shown in FIG. 6, it is assumed that the traffic signal controller 4 does not receive the transmission data 2 due to communication failure, for example.
In this case, the control unit 41 of the traffic signal controller 4 completes the future cycle (09:05) of the transmission data 1 when the centralized control by the signal control command for the current cycle (09:03) of the transmission data 1 ends. Perform centralized control by signal control commands.

Next, when the central control by the signal control command for the future cycle (09:05) of the transmission data 1 ends, the control unit 41 performs the central control by the signal control command for the future cycle (09:07) of the transmission data 1. To execute.
Next, when the centralized control by the signal control command for the future cycle (09:07) of the transmission data 1 is executed, the control unit 41 executes the continuous control for the next one cycle.

As described above, in the method of collectively transmitting the signal control commands for the current cycle (09:03) and the future cycle (09:04 or later), not only the signal control parameters for the current cycle but also the signals for the future cycle The traffic signal controller 4 can use the control parameters for centralized control.
Therefore, even if the traffic signal controller 4 cannot receive the signal control command due to a communication failure or the like, the traffic signal controller 4 can continue the centralized control according to the signal control parameters for the future cycle, and the future traffic flow data can be obtained. The traffic adaptation control based on it can be operated appropriately.

[Control mode determination processing]
FIG. 7 is a flowchart showing an example of control mode determination processing executed by the control unit 41 of the traffic signal controller 4.
As shown in FIG. 7, the control unit 41 of the traffic signal controller 4 determines whether there is a communication failure (step ST1). This determination is based on whether the unreceived time of the signal control command is a predetermined threshold value (for example, 10 seconds) or more, or whether the number of times the signal control command is unsuccessfully received is a predetermined threshold value (for example, 3 times) or more. Done.

When the determination result of step ST1 is affirmative (when there is a communication failure), the control unit 41 further determines that the difference between the current time and the time information is the future period Tf (=5×Tc: 5 minutes in the present embodiment). It is determined whether or not there is a signal control command within the range (step ST2).
When the determination result of step ST2 is affirmative (when there is a signal control command that is time information within the future period), the signal whose time information is the latest among the signal control commands for the current cycle and the future cycle Centralized control is executed according to a control command (step ST3).

When the determination result of step ST2 is negative (when there is no signal control command which is time information in the future period), continuous control which operates with the signal control parameter of the previous cycle is executed (step ST4).
When the result of the determination in step ST1 is negative (when there is no communication failure), the centralized control is executed by the signal control command having the latest time information among the signal control commands for this cycle (step ST5).

[Time length of future cycle]
In the above-described embodiment, in the case where the traffic signal controller 4 follows the current signal control parameter for at least one cycle in order not to confuse the driver of the vehicle 5, the time length of the future period Tf (=M XTc), it is preferable that the following relational expression (4) holds for the cycle length C to be executed by the traffic signal controller 4.
Tf=M×Tc≧C (4)

The reason is that in the case of the traffic signal controller 4 that follows the current signal control parameter for at least one cycle, the traffic signal controller 4 is provided with the signal control parameter to be executed in the future period Tf shorter than the cycle length C. However, the traffic signal controller 4 does not adopt the provided signal control parameter.

For the same reason, with respect to the traffic signal controller 4 capable of executing the terminal sensitive control, the time length (=M×Tc) of the future period Tf is as follows with respect to the cycle length C to be executed by the traffic signal controller 4. It is preferable that the relational expression (5) holds.
Tf=M×Tc≧C+Tk (5)
However, Tk: Sensitivity fluctuation range (seconds)
The sensitive variation width Tk is a variation amount of the step seconds (only in the present embodiment, enlargement) accompanying the execution of the terminal sensitive control.

For the same reason, for the traffic signal controller 4 that is executing the system control, the time length (=M×Tc) of the future period Tf is as follows with respect to the cycle length C to be executed by the traffic signal controller 4. It is preferable that the relational expression (6) holds.
Tf=M×Tc≧C+To (6)
However, To: Offset tracking width (seconds)
The offset tracking width To is a time variation amount (only expansion in the present embodiment) in the case of performing a process (offset tracking) of gradually changing the offset amount during system control.

[First Modification]
In the above-described embodiment, the signal control parameter included in the signal control command for the future cycle is not only the parameter calculated based on the predicted value of the traffic flow data of the intersection Ji as the original data, but also the signal which is determined to be the future implementation. It may be a control parameter.
Examples of the signal control parameter that is determined to be implemented in the future include the signal control parameter for instructing the “time control” and the signal control parameter for executing the “flash control”.

In this way, the signal control parameter for time control and flash control can be transmitted in advance by the signal control command with time information. Therefore, even if a communication failure occurs before the start of the time control or the flash control, the traffic signal controller 4 can execute those controls.
Therefore, the time information of the signal control command that causes the traffic signal controller 4 to perform the time control or the flash control may include the scheduled start time of those controls.

The embodiments described above are illustrative in all respects and not restrictive. The scope of rights of the present invention is shown by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

1 traffic signal control system 2 signal light device 4 traffic signal controller 5 vehicle 6 central unit 8 roadside sensor 10 roadside communication device 41 control unit (lower side control unit)
42 Lamp drive unit 43 Communication unit (lower side communication unit)
44 storage unit 45 computer program 61 control unit (upper side control unit)
62 display unit 63 communication unit (upper side communication unit)
64 storage unit 65 operation unit 66 computer program

Claims (9)

A central device that remotely controls traffic signal controllers installed at multiple intersections,
A control unit that generates the following first and second control commands for each predetermined control cycle,
A central unit comprising: a communication unit that collectively transmits both the generated first and second control commands for each control cycle to the traffic signal controller.
First control command: signal control command including signal control parameters for current cycle Second control command: signal control command including signal control parameters for future cycle The first control command includes
The current cycle includes time information indicating a scheduled start time of the signal control parameter to be executed by the traffic signal controller,
The second control command includes
The central apparatus according to claim 1, wherein time information indicating a scheduled start time of the signal control parameter to be executed by the traffic signal controller is included in the future cycle. The second control command includes
The central device according to claim 1 or 2, wherein at least one of the signal control commands including the signal control parameter based on the predicted value of the traffic flow data at the intersection is used as the original data. The second control command includes
Central device according to any one of the preceding claims, wherein at least one of the signal control commands is included, which includes the signal control parameters for future implementation. When the control cycle is Tc, the future period after the start time of the current cycle is Tf, the quotient obtained by dividing the future period by the control cycle is M, and the cycle length of the intersection is C,
The central apparatus according to claim 1, wherein a relational expression of Tf=M×Tc≧C is satisfied. The control cycle is Tc, the future period after the start time of the current cycle is Tf, the quotient obtained by dividing the future period by the control cycle is M, the cycle length of the intersection is C, and the sensitivity at the intersection is If the fluctuation range is Tk,
The central apparatus according to claim 1, wherein a relational expression of Tf=M×Tc≧C+Tk is established. The control cycle is Tc, the future period after the start time of the current cycle is Tf, the quotient obtained by dividing the future period by the control cycle is M, the cycle length of the intersection is C, and offset tracking at the intersection is performed. If the width is To,
The central apparatus according to claim 1, wherein a relational expression of Tf=M×Tc≧C+To is satisfied. A traffic signal controller installed at an intersection that is remotely controlled by a central device,
A communication unit that receives the following first and second control commands for each predetermined control cycle,
A control unit that controls the signal light color of the intersection by the signal control parameter of the latest signal control command of the received first and second control commands when a failure occurs in communication with the central device. Traffic signal controller equipped.
First control command: signal control command including signal control parameters for current cycle Second control command: signal control command including signal control parameters for future cycle A traffic signal control system comprising: a traffic signal controller installed at a plurality of intersections; and a central device for remotely controlling the traffic signal controller,
The central device is
A higher-order control unit that generates the following first and second control commands for each predetermined control cycle,
And a higher-level communication unit that collectively transmits both the generated first and second control commands for each control cycle, to the traffic signal controller.
The traffic signal controller,
A lower-level communication unit that receives the first and second control commands for each control cycle,
When a failure occurs in communication with the central device, a lower-order control unit that controls the signal light color of the intersection by the signal control parameter of the latest signal control command of the received first and second control commands. , A traffic signal control system having.
First control command: signal control command including signal control parameters for current cycle Second control command: signal control command including signal control parameters for future cycle

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