JP2002049985A - Traffic jam monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a traffic jam monitoring system which can accurately decide the state of a traffic jam that is caused at a road construction site. SOLUTION: This system includes the signals placed at every vehicle entrance of an alternate pass section where plural paths entering a single lane are prepared on a road and the vehicles traveling on the lane in different directions pass alternately in each prescribed permitted time, a vehicle detector which detects presence or absence of vehicle passing through the alternate pass section and a controller which controls the permitted entering directions of vehicles in the alternate pass section by switching the signal display, decides whether the vehicles traveling in the permitted entering directions that are detected by the vehicle detector passing the alternate pass section pass or not continuously in the permitted pass time and then decides occurrence of a traffic jam when the continuously passing events are caused in the same direction with each passing permission.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a traffic jam monitoring system.

[0002]

2. Description of the Related Art Road construction for installing water and sewage systems and information and communication is necessary for the development of basic social infrastructure, but is necessary for the period of construction, for living and production. It also has the problem of squeezing the road traffic. At present, in order to suppress the occurrence of traffic congestion and reduce the influence on road traffic, construction is performed at night or during daytime while avoiding high traffic hours in the morning and evening.
These have led to rising construction costs, soaring prices for social infrastructure, and deteriorating profits for construction companies. In addition, during nighttime construction, the problem of noise damage to local residents due to the construction is likely to occur.

Conventionally, as a method of monitoring traffic congestion, Japanese Patent Application Laid-Open No. H10-198886 (hereinafter referred to as a first prior art) and Japanese Patent Application Laid-Open No. H10-320686 (hereinafter, referred to as a first prior art) have been proposed.
(Referred to as second prior art). In the first prior art, the situation of traffic congestion is constantly monitored by a sensor that is fixedly installed on a main road and detects the number of vehicles passing and the speed, and the number of vehicles passing per unit time is equal to or more than a predetermined value, When the speed of the passing vehicle is equal to or lower than a predetermined value, it is determined that the vehicle is congested. And the result is VICS
(Registered trademark) (road traffic information communication system)
It is displayed on a display panel, a car navigation system, or the like, and is notified to a traveling driver or the like. In the second prior art, a visual sensor or the like is provided in the traffic congestion monitoring sensor to extract the characteristics of the vehicle body, so that a change in the movement time between the upstream traffic congestion monitoring sensor and the downstream traffic congestion monitoring sensor is detected. Thus, even if the interval of the traffic jam monitor is large, the situation of the traffic jam during the interval is more accurately found.

[0004]

However, the prior art has the following problems. That is,
In the first prior art, the fixed traffic congestion monitoring sensor has a problem of installation cost, and cannot be completely installed on all roads. 200-300m in few urban areas
They are installed at intervals, but in most areas, they are installed at higher intervals on arterial roads. Therefore, the detected traffic congestion is also limited to a large-scale traffic congestion that exceeds the sensor installation interval on the main road. It goes without saying that traffic cannot be captured on a road on which these sensors are not installed. In addition, most of the traffic congestion generated due to road construction is of a scale of 100 to 500 m, and even on a road on which these sensors are installed, these sensors cannot be captured or can be captured. Even if it is possible, it is not possible to determine from which position between the sensors the traffic jam is occurring. Road works are often performed on general roads that are used as places of living, and even small traffic jams can have a significant impact on the lives of nearby residents.

[0005] In the second prior art, traffic congestion can be more accurately obtained on a road without a branch, such as a motorway, but like the first prior art,
It is not possible to determine where the traffic congestion occurs between the traffic congestion monitoring sensors, and it cannot be applied to a road where an intersection or a store exists between the traffic congestion monitoring sensors. In other words, the degree of traffic congestion is determined by avoiding the difference between the travel time during the night when the road is vacant and the travel time during the day when there is heavy traffic, and errors due to stop times at intersections (variations not related to traffic congestion). For example, if the travel time of a certain vehicle is 10 minutes, it is difficult to determine whether this is due to traffic congestion or whether the vehicle has been shopping at a store between sensors. Further, when the case where the traffic congestion monitoring sensor erroneously detects the characteristics of the vehicle is included, it becomes more difficult to determine the degree of traffic congestion.

[0006] When traffic is completely congested, the travel time for the vehicle itself is not shortened even if the vehicle interval is shortened.
Instead of moving slowly as a whole, they act as if they come to a stop and have space ahead and move together. As before, it monitors only one approaching vehicle,
If there is a lot of vehicles that take the above action due to complete congestion, a space is created between the vehicles inside the congestion, and a small number of vehicles move in front of the sensor at a certain speed, so it is determined whether or not congestion has occurred. Becomes difficult. For this reason, it is necessary to statistically analyze the behavior of the vehicle, and there is a problem of lack of responsiveness. If not only one sensor but also a plurality of sensors are provided, the installation cost increases and a similar problem occurs when there is a space between vehicles in front of the sensors. Further, traffic guidance in road construction is often performed by security guards.The security guards grasp the situation of traffic congestion and communicate the information to a road traffic information center or the like by telephone or the like during the guidance work. Is dangerous and quantitative and real-time monitoring of congestion is not possible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a traffic jam monitoring system capable of accurately judging a traffic jam occurring at a road construction site.

[0008]

In order to achieve the above object, a vehicle having a plurality of approach roads entering one lane of a road and having different traffic directions in the one lane is provided at predetermined intervals. A traffic signal provided at the entrance of the vehicle, a vehicle detection device for detecting the presence or absence of a vehicle passing through the alternating traffic section, and an alternate traffic section by switching the display of the traffic light. While controlling the approach permission direction to, the vehicle in the approach permission direction detected by the vehicle detection device is detected to pass through the alternate traffic section, it is determined whether or not to continue through the passage permission time, continue to A control device that determines that traffic congestion has occurred when the passing event occurs continuously for each pass permission in the same approach direction. Further, the vehicle detection device measures a distance to a vehicle.

[0009] That is, when the event that the vehicle continuously passes continuously occurs within the permitted passage time (blue time), it is detected that the traffic congestion with the traffic signal at the head has occurred. Can be. Also, by measuring the distance to the vehicle,
Immediately after measuring the distance and speed of a certain vehicle, it becomes possible to measure the distance and speed of the vehicle following the vehicle. According to this, when the traffic is completely congested, the movement time for the vehicle itself is not shortened even if the vehicle interval is shortened, so that when the vehicle stops and there is space ahead, it moves collectively rather than moving slowly as a whole. Even if there is a space between the vehicles in front of the vehicle detection device, the distance and the speed of the vehicle stopped there can be measured, so that the traffic jam occurrence state can be accurately determined.

A first vehicle discriminating device is provided at a first point near the road construction site on the upstream side in the traffic direction for monitoring traffic congestion at the road construction site, and detects a characteristic of a passing vehicle to determine the vehicle. A second vehicle discriminating device provided at a second point upstream of the road construction site and separated by a predetermined distance from the first point to detect a feature of a passing vehicle and discriminate the vehicle;
The travel time of the vehicle from the second point to the first point when the vehicle detected by the second vehicle discriminating device is detected by the first vehicle discriminating device, and the travel time of the vehicle when no congestion occurs. The traffic jam time, which is the difference between the travel time and the normal travel time, is determined from the normal travel time from the second point to the first point, and the situation of the traffic jam based on the road construction site is determined based on the determined traffic jam time. And a control device that performs the control. Further, the road construction site has a plurality of approach roads that enter one lane of the road, and has an alternating traffic section in which vehicles in different traffic directions alternately pass through the one lane at predetermined permission times,
The first point is provided with a traffic light indicating an access permission direction to the alternating traffic section, the control device controls the approach permission direction to the alternating traffic section by switching the display of the traffic light, and a traffic permission time, When the vehicle detected by the first vehicle discrimination device does not continuously pass, the travel time at that time is updated as a normal travel time.

That is, since the vehicle is determined, the traveling time between two points of the vehicle can be accurately detected. Then, the traffic jam time of the traffic jam with the road construction site at the top can be obtained from the difference from the normal travel time, and the traffic jam status can be determined. It is also possible to calculate the congestion distance based on the obtained congestion time and the number of vehicles passing per unit time. Also, a traffic signal is installed at the road construction site, and if the passing vehicle is interrupted before the passage permission time (blue time) elapses, that is, if there is no congestion, the traveling time at this time is set to the normal traveling time. Has been updated as. For this reason, since the normal traveling time depending on the traffic volume that changes depending on the time zone can be updated to the latest one in the time zone, an accurate congestion time can be obtained.

A first passage number measuring means provided at a first point near the road construction site on the upstream side in the traffic direction for monitoring traffic congestion at the road construction site and measuring the number and the number of vehicles passing therethrough; A second passing number measuring means provided at a second point on the upstream side of the road construction site and separated by a predetermined distance from the first point and measuring the presence or absence and the number of passing vehicles;
A first accumulating means for calculating the cumulative number of passing vehicles based on the data measured by the first passing number measuring means, and a second accumulating means for calculating the cumulative number of passing vehicles based on the data measured by the second passing number measuring means. A standby vehicle that calculates the difference between the cumulative number of vehicles passing through the second point accumulated by the second accumulating unit and the cumulative number of vehicles passing through the first point accumulated by the first accumulating unit; And a control device for determining the number of vehicles and determining a congestion condition based on the road construction site based on the determined number of waiting vehicles. Further, the road construction site has a plurality of approach roads that enter one lane of the road, and has an alternating traffic section in which vehicles in different traffic directions alternately pass through the one lane at predetermined predetermined time intervals. The point is provided with a traffic light indicating an entry permission direction to the alternating traffic section, and the control device controls the approach permission direction to the alternating traffic section by switching the display of the traffic signal, and also allows a traffic light passing time, a first time. When the vehicle detected by the vehicle discrimination device does not continuously pass, the cumulative number of vehicles passing at the first point and the cumulative number of vehicles passing at the second point are each updated to zero.

That is, from the difference between the cumulative number of vehicles passing through the second point and the cumulative number of vehicles passing through the first point, the number of vehicles on standby in the traffic congestion heading at the road construction site can be determined, and the congestion state can be determined. it can. Also, since the number of passing vehicles is measured, the apparatus is simpler and less expensive than a discriminating apparatus using image processing or the like. In addition, a traffic light will be installed at the road construction site,
If the passing vehicle is interrupted before the passage permission time (blue time) elapses, that is, if there is no traffic jam,
The cumulative number of vehicles passing both locations has been updated to zero. For this reason, the influence of an error due to a vehicle entering a branch road, a store, or the like between the two points can be further reduced, and the congestion state can be accurately determined.

Further, the traffic congestion monitoring system includes a traffic congestion information panel upstream of the second point, and the control device includes:
It is characterized in that the distance of the congestion from the point, the distance between the first point and the congestion information board, or the distance between the end of the congestion and the congestion information board is displayed on the congestion information board.

That is, since the driver can be informed of the base point of traffic congestion and the scale of the traffic congestion on the traffic congestion display panel, the driver can bypass the traffic congestion and reduce the traffic volume near the construction site to reduce the traffic congestion. Can be eased.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, a first embodiment will be described. FIG. 1 is an explanatory diagram showing an installation state of the traffic congestion monitoring system according to the present embodiment, and exemplifies a case where construction is performed on a T-shaped road. FIG. 2 shows a system block diagram of the traffic congestion monitoring system. 1 and 2, a road 1 is a two-lane road 1 extending in the left-right direction in the figure.
It is composed of an approach path 8 which is substantially orthogonal to this. In the lower lane of the two-lane road 1 in the figure, a construction section 10 partitioned by a conical barricade 9 is provided, and the opposite lane (the upper side in FIG. It has become. The approach road 8 is provided in the alternating traffic section 2. Hereinafter, the traveling direction of the vehicle traveling in the lane on the side where the alternating traffic section 2 is provided is the direction A, and the traveling direction of the vehicle traveling on the lane on the side where the construction section 10 is provided is B.
The direction and the traveling direction of the vehicle traveling on the approach road 8 are referred to as the C direction.

At each of the entrances 3A, 3B, 3C where vehicles enter the alternate traffic section 2, there are provided traffic lights 7A, 7B, 7C for indicating passing directions in which the vehicle can pass. Each of the traffic lights 7A, 7B, 7C is electrically connected to the main controller 14, displays a blue or red signal based on the command, and determines the traveling direction A, B, C of the vehicle. The vehicle approaches the alternating traffic section 2 from the A direction, the B direction, or the C direction, and travels in the alternating traffic section 2 according to the display of each of the traffic lights 7A, 7B, 7C. The A-direction approaching section 11A, the B-direction approaching section 11B, and the C-direction approaching section 11C are provided before the alternating traffic section 2 in the A-direction, the B-direction, and the C-direction, respectively. When the traffic lights 7A, 7B, 7C in the traveling direction are red, the vehicle is in this approach zone 11
A, 11B, and 11C, approaching the alternate traffic section 2 and approaching the alternate traffic section 2 before the traffic lights 7A,
Stop until 7B and 7C turn blue. At this time, the elapsed time since each of the traffic lights 7A, 7B, and 7C finally turned blue is referred to as a standby time in each direction.

In the approaching section 11, the vehicle traveling toward the stop or the alternate traffic section 2 is moved to the approaching vehicle 13.
, And from the approaching vehicle 13 at the front,
The distance to is called the approach distance. As shown in the direction B in the figure,
When the approaching vehicle 13 is stopped before the traffic light 7B, the approaching distance is zero. Furthermore, the time required for the traveling approaching vehicle 13 to reach the alternate traffic section 2 is defined as:
Called approach time. The approach time is roughly derived from (approach distance) / (speed of approaching vehicle 13), and when approaching vehicle 13 is stopped in front of traffic light 7B as in the direction B, the approach time is zero. A vehicle traveling in the alternate traffic section 2 according to the green light is referred to as a passing vehicle 23. A construction vehicle 15 such as a hydraulic shovel or a dump truck works on the construction section 10, and a part of the construction vehicle 15 enters and exits through the alternating traffic section 2. When the construction vehicle 15 enters and exits the construction section 10, all traffic lights are turned red to enter and exit. A vehicle detection device 12 using a millimeter wave is installed as a traffic flow monitoring device on the shoulder of the alternate traffic section 2 and is electrically connected to the main controller 14.

FIG. 3 is a structural diagram of the vehicle detecting device 12. As shown in FIG. As shown in FIG. 3, the vehicle detection device 12 includes a millimeter wave transmitter 5 for transmitting a millimeter wave, a rotatable reflector 19 for reflecting the millimeter wave, and a millimeter for receiving a millimeter wave reflected back from an object. Has a receiver 6. The reflection plate 19 is always rotated 360 degrees by, for example, a motor (not shown), so that the millimeter wave is
Sent in 0 degree direction. The vehicle detection device 12 receives the millimeter wave reflected back from the object, and analyzes and detects the position, speed, and size of the object. The detection distance of such a vehicle detection device 12 is, for example, about 120
m, the length of the approaching sections 11A, 11B, 11C can be set up to 120 m. The resolution of detection is, for example, about 1 to 2 m. Vehicle detection device 1
Numeral 2 is electrically connected to the main controller 14 so that a detection result can be displayed on a touch panel type display device 18 attached to the main controller 14.

That is, the vehicle detecting device 12 is provided in the direction A,
It is possible to detect the distance, speed, and number of approaching vehicles 13 and passing vehicles 23 in the B direction and the C direction. The vehicle detecting device 12 always detects the speed of the vehicle at the same time as the distance of the vehicle so as to avoid erroneously recognizing a vehicle traveling in a direction away from the alternating traffic section 2 as the approaching vehicle 13. . That is, the vehicle traveling in the direction away from the alternating traffic section 2 is irrelevant to the traffic control in the alternating traffic section 2 and is ignored. Further, among vehicles stopped in the approaching sections 11A, 11B, and 11C, even if the signal in that direction is green, but the vehicle has been stopped for a certain period of time (for example, one minute), Ignore existence.

The vehicle detection device 12 includes the approaching sections 11A, 1A.
In order to accurately indicate 1B and 11C and accurately detect the vehicle, the following work is performed after installation. That is, the vehicle detection device 12 detects an object such as a barricade 9, a guardrail, a tree at the side of the road, or a running vehicle or the like placed on the road, and displays it on the display device 18. Based on this, the worker inputs in advance what the object displayed on the display device 18 is through the touch panel to the main controller 14 and performs teaching. In addition to this information,
A range such as a road, a construction section 10, approach sections 11A, 11B, and 11C in each direction of A, B, and C, and an alternate traffic section 2 is designated. At this time, if a reflector that appropriately reflects the millimeter wave is temporarily installed at the boundary between the sections, the vehicle detection device 12 accurately detects these sections, and teaching becomes easy.

Next, using such a vehicle detection device 12, an approaching vehicle 13 traveling or stopping in each approaching section 11A, 11B, 11C and a passing vehicle 23 traveling in the alternate traffic section 2 are detected. A procedure for controlling the display of each traffic light so that traffic flows smoothly based on the state of each approaching vehicle 13 and passing vehicle 23 will be described.

First, FIG. 4 shows a main flowchart showing the overall flow of control. As shown in the figure, when the power is turned on to the main controller 14 (S1), the main controller 14 first sets the signals in all directions to red (S2). Then, the passing direction A, B, or C of the vehicle is determined based on a predetermined procedure described later (S3), the signal in the passing direction A, B, or C is turned blue (S4), and the signal in that direction is set. The traffic flow is measured (S5). Then, when a time (blue time) for turning a signal in that direction determined by a procedure described later elapses (blue time), a traffic jam situation in that direction is determined (S6), and a blue time in that direction is set (S7). S
Return to 2. In this flowchart, S2 and S3
Is referred to as a full stop mode, S4 and S5 are referred to as passing modes in the A, B, or C directions, S6 is referred to as a traffic jam determination mode, and S7 is referred to as a blue time setting mode. It should be noted that the order of the traffic jam determination mode (S6) and the blue time setting mode (S7) may be interchanged.

Of the above procedures, the full stop mode will first be described in detail. FIG. 5 shows a flowchart of the all stop mode. First, the main controller 14 sets signals in all directions to red (S11), and waits for a predetermined time of about one second to elapse (S12). Then, the presence or absence of the passing vehicle 23 traveling in the alternate traffic section 2 is determined by the vehicle detector 12 (S13). If there is a passing vehicle 23 in the alternating traffic section 2 in S13, a predetermined margin time that is sufficient for the passing vehicle 23 to pass through the alternating traffic section 2 has elapsed since the stop mode was set. It is determined whether or not (S14), and if the margin time has not elapsed, the process returns to S11. If the allowance time has elapsed in S14, it is determined that an unexpected event has occurred, for example, that the vehicle has stopped in the alternate traffic section 2 or that the vehicle detector 12 has failed. To output an alarm (S15), and S1
Return to 1. Note that the alarm may be an alarm sound by a buzzer, a siren, or the like, lighting of a warning lamp, display on the display device 18 of the main controller 14, or the like.

If there is no passing vehicle 23 in the alternate traffic section 2 in S13, the approach sections 11A, 11A in all directions are used.
The presence or absence of the approaching vehicle 13 is detected for B and 11C, and it is determined whether there is the approaching vehicle 13 in only one direction (S1).
6) If there is an approaching vehicle 13 only in the y direction, the process shifts to the passing mode in the y direction (S17). Otherwise, it is determined whether there are vehicles approaching in a plurality of directions (S18).
When the approaching vehicle 13 is detected in multiple directions in S18,
The waiting times that have elapsed since the turning of the approaching vehicle 13 in each direction to the last blue color are compared, the direction in which the waiting time is the longest is selected, and the mode is shifted to the passing mode in the selected direction (S19, S20). ). If no approaching vehicle 13 is detected in a plurality of directions in S18, it is determined that there is no approaching vehicle in any of the directions A, B, and C, and the process returns to S11.

That is, in the all stop mode, the approaching sections 11A, 11B, and 11C are provided before the alternating traffic section 2, and based on the presence or absence of the approaching vehicle 13 traveling or stopping in this approaching section, Is determined to be blue.

Next, for a passing mode in a certain direction, A
The direction will be described as an example. FIG. 6 shows a flowchart of the passage mode. First, the main controller 14
The current time t is substituted for the last passing time tA in the A direction, and A
The elapsed time T after switching to the direction passing mode is calculated (S21). This last passing time tA is the same as the time at S19
Is a reference when comparing the waiting time in each direction. Then, the signal in the direction A is set to blue, and the signals in the other directions (directions B and C) are all set to red (S22). Next, it is determined whether or not the elapsed time T after switching to the passing mode in the A direction has passed the blue time T1A in the A direction determined by a procedure described later (S23). If the elapsed time T has passed the blue time T1A in the A direction, the traffic jam counter value CjA in the A direction is advanced by "+1" (S24), and the flow returns to the main flow shown in FIG.

In step S23, the elapsed time T of the passing mode
If the blue time T1A in the A direction has not elapsed, it is determined whether there is no approaching vehicle 13 and no passing vehicle 23 in the A direction and there is an approaching vehicle 13 in the other direction (S25). If there is no approaching vehicle 13 or passing vehicle 23 in the A direction and there is an approaching vehicle 13 in the other direction, the traffic jam counter value CjA in the A direction is set to "CjA- (T1A-T) / 5" (S26). It returns to the main flow shown in FIG. In S25, if there is an approaching vehicle 13 or passing vehicle 23 in the A direction, or if there is no approaching vehicle 13 in the other direction, it is determined whether there is an approaching vehicle 13 in the A direction (S27). If there is an approaching vehicle 13 in the A direction, the approach time of the approaching vehicle 13 in the A direction is calculated by “(approach distance) / (speed of the approaching vehicle 13)” (S28). If it is determined that there is no, the approach time in the A direction is set to "infinity".
(S30), the process proceeds to S29, and it is determined whether the elapsed time T in the passing mode has reached 5 seconds, the approaching vehicle 13 is in the other direction, and the approach time in the A direction is longer than 8 seconds. If “YES” in S29, the process proceeds to S26, and if “NO” in S29, the process returns to S21. Here, the comparison between the elapsed time T and 5 seconds is as follows.
Once the direction is changed to blue, the color is not switched to red immediately, but is kept for at least 5 seconds.
The reason why the approach time is compared with 8 seconds is that when the approach time is 8 seconds or less, it is considered that the speed of the approaching vehicle is high, or the distance to the traffic light is short, etc. In such a case, it is to determine that the approaching vehicle should be passed at the current green light.

That is, in the passing mode, when the approaching vehicle 13 in the A direction continuously continues, the passing mode in the A direction is continued until the blue time T1A in the A direction elapses.
After the elapse of the blue time T1A, the traffic jam counter value C in the A direction
jA is advanced by "+1". Also, the blue time T1A in the A direction
If the approaching vehicle 13 in the direction A is interrupted or the approach time is long before the time elapses, the traffic jam counter value C in the direction A
jA is set to "CjA- (T1A-T) / 5". For example, the current traffic jam counter value CjA in the direction A is 6,
If the blue time T1A in the direction A is 30 seconds and the passing time T in the passing mode has passed 20 seconds, there is no approaching vehicle from the direction A and there is an approaching vehicle 13 in the other direction. The value CjA is set to "6- (30-20) / 5"
= "4", etc.

Next, the congestion determination mode in a certain direction will be described by taking the direction A as an example. FIG. 7 shows a flowchart of the congestion determination mode. First, the main controller 14 determines whether or not the traffic jam counter value CjA in the direction A has exceeded 10 (S31).
It is determined that there is no traffic congestion in the direction, and the process returns to the main flow shown in FIG. If it exceeds 10, it is determined that there is congestion in the direction A, and a GPS surveying instrument (not shown) provided in the traffic light 7A
The GPS measurement position of the traffic light 7A measured by the above and the traffic congestion counter value CjA in the A direction are transmitted to the traffic control center by mobile radio or the like as traffic data in the A direction (S3).
2) The A-direction traffic jam counter value CjA is transmitted to the A-direction traffic jam information panel (not shown) installed at an arbitrary position upstream in the A direction via a wireless LAN or the like (S33), and is shown in FIG. Return to the main flow.

That is, in the traffic congestion determination mode, the traffic congestion counter value CjA which increases and decreases in the passing mode is monitored, and when it exceeds a predetermined value (10 in this embodiment), it is determined that traffic congestion has occurred, and Information on traffic congestion is transmitted to traffic control centers.

Next, the blue time setting mode in a certain direction will be described by taking the direction A as an example. FIG. 8 shows a flowchart of the blue time setting mode. First, the main controller 14 sets the blue time T1A in the A direction to “T1A + (A
(Congestion counter value CjA in the direction)-(maximum value Cjmax of congestion counter values in other directions) "(S41). As a result, if T1A becomes longer than 60 seconds (S42), T1
Is set to 60 seconds (S43), and if T1A is shorter than 25 seconds (S44), T1 is set to 25 seconds (S45),
It returns to the main flow shown in FIG. That is, in the blue time setting mode, the blue time T1 in that direction is set based on the traffic jam counter value in that direction and the traffic jam counter value in other directions, and the upper and lower limits are set.

As described above, according to the present embodiment, when the vehicle continuously passes the blue time T1 of the signal installed at the construction site, the counter value is advanced by "1", and the counter value is increased before the blue time T1 elapses. If the passing vehicle is interrupted by the elapsed time T, the traffic jam counter which returns the counter value to "(T1-T) / 5" is provided. When the counter value reaches a predetermined value, it is determined that traffic congestion has occurred. In addition, the degree of congestion can be known to some extent from the congestion counter value.
Then, traffic congestion information can be sent to traffic control centers and traffic congestion bulletin boards to inform drivers, nearby residents and construction contractors of the traffic congestion status in real time. Can be alleviated.
If the traffic congestion can be alleviated, the construction contractor will be able to carry out construction during the day instead of at night, which will reduce construction costs,
Also, Jus, a dispatcher of construction vehicles that transport materials and excavated soil
t InTime can be achieved, and the productivity at the construction site can be improved.

If there is no approaching vehicle from a certain direction, the control is performed so that the signal in the other direction is switched to blue even if the blue time in that direction remains, so that the traffic volume passing through the alternate traffic section is reduced. It can be increased and traffic congestion can be suppressed. Furthermore, when switching the blue direction,
Since the presence or absence of an approaching vehicle and the length of the waiting time are taken into consideration, the vehicle can pass through the vehicle efficiently, eliminating unnecessary waiting time and preventing the driver from feeling irritated. Further, by comparing the degree of congestion in each direction (congestion counter value), the blue time in each direction is made variable, and the blue time in the direction with a large degree of congestion is lengthened, so that congestion can be suppressed. .

In this embodiment, the presence or absence of the approaching vehicle 13 and the distance and speed of the approaching vehicle 13 are measured by the vehicle detection device 12 to detect whether or not the vehicle is continuing, and to monitor the traffic congestion. . In particular, in the present embodiment, since the distance of the approaching vehicle 13 is measured, a vehicle continuing from behind can be measured. When traffic is completely congested, the movement time is not shortened for the vehicle itself even if the vehicle interval is shortened, so rather than moving slowly as a whole, act as a unit when the vehicle stops and there is space ahead and collectively Therefore, even when there is a space between the vehicles in front of the vehicle detection device 12, the speed of the vehicle stopped thereover can be measured, so that the traffic jam occurrence state can be accurately determined. For this reason, even small-scale traffic congestion generated due to road construction or the like can be accurately grasped.

Next, a second embodiment will be described. FIG. 9 is an explanatory diagram illustrating an installation state of the traffic jam monitoring system according to the present embodiment, and illustrates an example in which traffic jam on one side is monitored from a construction site of a road on which road construction is being performed. FIG. 10 shows a system block diagram of the traffic congestion monitoring system. In FIGS. 9 and 10, the construction section 10 is located on one lane of the two-lane road 1 that branches off from the main road 25.
Is provided, and the lane on the opposite side of the construction section 10 is an alternate traffic section 2. The traveling direction of the vehicle 28 traveling from the main road 25 toward the alternating traffic section 2 is defined as an A direction. Between the main road 25 and the construction section 10, there are branch roads 26 and stores 29.

At each of the entrances 3A and 3B where the vehicle 28 enters the alternate traffic section 2, there are provided traffic lights 7A and 7B for indicating the passing directions in which the vehicle 28 can pass. Each traffic light 7
A and 7B are electrically connected to the main controller 24, display a blue or red signal based on the command, and determine the traveling direction of the vehicle in the alternate traffic section 2. At a point P on the two-lane road 1 near the junction with the main road 25 and at a point Q on the two-lane road 1 near the traffic light 7A, a TV camera, an image processing device, or the like is provided as a traffic flow monitoring device. Vehicle discriminating devices 22P and 22Q are provided respectively. Each of the vehicle discriminating devices 22P and 22Q detects the number of the license plate of the vehicle 28 traveling in the A direction by pattern matching, and transmits the read number together with the detection time to the electrically connected main controller 24. . Congestion information boards 27, 27 electrically connected to the main controller 24 are respectively installed on the shoulders of the main road 25 in front of the junction with the two-lane road 1 in each of the up and down lanes. The traffic congestion information board 27 can display characters and graphics with an LED or the like, and displays the presence or absence of traffic congestion, the length of traffic congestion, and the like based on a command from the main controller 24.

Next, a control flow of the traffic congestion monitoring system according to this embodiment will be described with reference to FIG. First,
The main controller 24 controls the vehicle identification device 22 at the point P.
The number of the vehicle 28 detected by P and the detection time are received and stored (S51). Next, the vehicle discriminating device 2 at the point Q
The number of the vehicle 28 detected by 2Q is received (S5).
2) It is determined whether there is a number that matches the number detected at the point P (S53). If there is no matching number, the process returns to S51. If there is a matching number, the travel time of the vehicle 28 from the point P to the point Q is calculated from the current time and the detection time of the number at the point P (S5).
4). Next, using the calculated travel time, for example, the past 5
The average travel time of the trips is averaged, or the average travel time is calculated by a formula such as “(previous average travel time) × 0.8 + (current travel time) × 0.2” (S55).
The average traffic time is calculated from the calculated average travel time and the normal travel time of the vehicle 28 from the point P to the point Q described below (S56). Then, the vehicle discriminating device 22Q at the Q point
The GPS measurement position of the vehicle discriminating device 22Q at the Q point measured by a GPS surveying instrument (not shown) provided in the vehicle and the average congestion time are transmitted to the traffic control center by mobile radio or the like as congestion data in the A direction. Then (S57), the average congestion time is transmitted to the congestion information board 27 installed on the main road 25 by wireless LAN or the like (S58), and the process returns to S51.

The above-mentioned normal traveling time is the traveling time of the vehicle 28 from the point P to the point Q when there is no congestion.
Since it changes greatly depending on the time zone, it is necessary to reset when traffic congestion does not occur. For example, even if the travel time from point P to point Q is the same for three minutes, if the traffic volume is low during the night, one minute is spent on the traffic signal queue and the remaining two minutes There is a case where the user waits for a traffic light (in this case, traffic congestion time = 2 minutes).
In some cases, it takes minutes and there is no extra waiting time due to the construction signal (in this case, congestion time = 0 minute). This difference can be ignored if monitoring the macro traffic congestion situation. However, in the notification of the small traffic congestion situation on the local road and the delivery of Just In Time of the material to the construction site, these differences can be ignored. Has a great effect on local residents and contractors. When resetting the normal traveling time, it is confirmed that there is no traffic congestion by the guard or the worker, "No traffic congestion" is input to the main controller 24, and the average traveling time calculated in S55 at that time is the normal traveling time. It may be updated as time. Further, the vehicle discrimination device 22Q detects that the passing vehicle is interrupted before the elapse of the blue time T1A of the traffic light 7A, and notifies the main controller of “no traffic jam”.
A signal may be transmitted, and the average travel time calculated in S55 at that time may be updated as the normal travel time.

In this embodiment, the traffic jam time is measured and transmitted to the traffic control center. However, the traffic jam distance may be calculated and transmitted. In this case, the congestion distance is
It can be roughly calculated from “(congestion time) × (number of vehicles passing per hour) × (average inter-vehicle distance + average vehicle length)”.

In this embodiment, the apparatus for reading a license plate has been described. However, for example, a scan-type laser sensor or the like may be used to capture the external features of the passage area. That is, for example, the height change data of the continuously collected vehicles may be normalized, and a matching vehicle may be obtained after performing fast Fourier transform. Alternatively, the height of the vehicle is measured and its passing pattern (for example, low, low,
, Low, high, etc.), and the time at which the matched portion is detected may be compared. The update timing of the average congestion time may be about once every 10 minutes, for example, so that it is not necessary to determine all vehicles and measure the transit time.

As described above, according to the present embodiment, the vehicle is determined based on the license plate number and the like using each of the vehicle determination devices 22P and 22Q.
Even if there is a vehicle that has turned toward the fork 26 between the point and the point Q or a vehicle that has entered the store 29, the vehicle passes the point P and reaches the point Q ignoring them. Vehicle 2
8 accurately detects the travel time. In addition, when the traffic time of the vehicle 28 from the point P to the Q point when there is no traffic congestion is taken as the normal travel time, the traffic congestion time is obtained from the difference between the average travel time and the normal travel time. It is possible to accurately detect the traffic congestion state in consideration of the influence of the traffic volume due to the belt. In addition, since the downstream vehicle discriminating device 22Q is installed in a traffic flow bottleneck such as a road construction site, the base point of the traffic jam can be specified, and accurate traffic information such as “road construction site” With v
vm traffic jam "can be obtained. Then, traffic congestion information can be sent to traffic control centers and traffic congestion bulletin boards to inform drivers, nearby residents and construction contractors of the traffic congestion status in real time. Can be expedited.

Further, the traffic light 7A is installed near the vehicle discriminating device 22Q on the downstream side, and if the passing vehicle is interrupted before the elapse of the blue time T1A of the traffic light 7A, it is determined that there is no traffic jam. By updating the travel time at this time as the normal travel time, a more accurate traffic jam time can be obtained from the latest normal travel time for each time zone.
If the normal traffic time cannot be updated for a predetermined time while the traffic congestion state continues, the data may be updated from the database up to the previous day with the data at the time.

Next, a third embodiment will be described. FIG. 12 is an explanatory diagram illustrating an installation state of the traffic congestion monitoring system according to the present embodiment, and illustrates an example in which traffic congestion on one side is monitored from a construction site of a road on which road construction is being performed. FIG. 13 shows a system block diagram of the traffic congestion monitoring system. 12 and 13, the vehicle discriminating devices 22P and 22P are different from FIGS.
The configuration is the same except that the number-of-passes measuring devices 32P and 32Q are provided as traffic flow monitoring devices in place of 22Q. Therefore, only different portions will be described, and description of common portions will be omitted. Passage number measuring devices 32P, 32Q
Is equipped with a millimeter wave oscillator that emits a millimeter wave in a predetermined direction, and a millimeter receiver that receives a millimeter wave reflected back from an object. Is detected, and the count value of the number of vehicles passing is detected at predetermined time intervals by the main controller 3.
4

Next, a control flow of the traffic congestion monitoring system according to this embodiment will be described with reference to FIG. First,
The main controller 34 counts the number-of-passes measuring device 32P at the point P, and every predetermined time (for example, every 20 seconds)
(S6)
1). Next, the passing number measuring device 32Q at the point Q counts and receives the number of passing vehicles 28 transmitted at predetermined time intervals (S62), and the number of passing vehicles Nq per time at the Q point.
Is greater than the number of passing vehicles per hour (predetermined value) during traffic congestion, and it is determined whether the number of passing vehicles Np per hour at point P and the number of passing vehicles Nq per hour at point Q are substantially equal (S6).
3).

If "NO" in S63, there is no traffic congestion between the P point and the Q point, or the rear end of the congestion is between the P point and the Q point. The number of passing vehicles at the point and the Q point is respectively accumulated (S64), and P
By subtracting the total number of passing vehicles at the point Q from the total number of passing vehicles at the point, the number of standby vehicles traveling in the direction A between the points P and Q is calculated (S65). Next, the congestion time Tj is calculated by “(the number of vehicles on standby) / (the number of passing vehicles Nq per point Q)” (S66), and the congestion time Tj for the past five times is calculated using the calculated congestion time Tj. Average or "((last average congestion time) x 0.8+
The average congestion time is calculated by a calculation formula such as ((current traffic jam time Tj) × 0.2) (S67). And Q
The mobile unit detects the GPS measurement position of the passing vehicle number measuring device 32Q at the Q point measured by a GPS surveying instrument (not shown) provided in the passing vehicle number measuring device 32Q at the point, and the average traffic time as traffic data in the A direction. The average congestion time is transmitted to the traffic control center by radio or the like (S68), the average congestion time is transmitted to the congestion information board 27 installed on the main road 25 by wireless LAN or the like (S69), and the process returns to S61.

If "YES" in S63, the rear end of the traffic congestion has reached the point P, and a GPS surveying instrument (not shown) provided in the passing number measuring device 32Q at the Q point. Apparatus 32 for measuring the number of passing vehicles at the measured Q point
The GPS measurement position of Q and the fact that the congestion time is equal to or longer than the "congestion time Tj" are transmitted to the traffic control center via mobile radio or the like as congestion data in the A direction (S70). The fact that the congestion time is equal to or longer than the "congestion time Tj" is transmitted to the public information board 27 via a wireless LAN or the like (S71), and the process returns to S61.

In S64 and S65, the number of vehicles passing at points P and Q is respectively accumulated, and the number of waiting vehicles traveling in the direction A between points P and Q is calculated from the difference therebetween. However, even if the vehicle passes the point P, the vehicle passing the point P does not necessarily pass the point Q due to turning to the branch road 26 or completing the business at the store 29 and turning back. An error occurs in the total number of passing vehicles at a point. To reduce this error, it is desirable to reset the total number of passing vehicles. For example, after confirming that there is no congestion by a guard or a worker, "No traffic congestion" is input to the main controller 34, and S
What is necessary is just to update the total of the number of passing vehicles at the point P and the point Q calculated at 64 as zero. Also, the passing vehicle number measuring device 32Q detects that the passing vehicle is interrupted before the blue time T1A of the traffic light 7A has elapsed, and transmits a “no traffic jam” signal to the main controller 34, and the S
“Cumulative number of vehicles passing through P point and Q point” calculated in 64
May be updated as “0”. Also, due to good visibility, security guards and workers
When it is possible to check the number of standby vehicles traveling in the direction A between the point and the point Q, a guard or a worker inputs the “number of standby vehicles” to the main controller 34 by keyboard. "(Total number of vehicles passing point P)
= (P keyboard input standby vehicle number), (total number of vehicles passing at point Q) = 0 ”.

In this embodiment, the traffic jam time is measured and transmitted to the traffic control center. However, the traffic jam distance may be calculated and transmitted. In this case, the congestion distance is
It can be roughly calculated from “(the number of waiting vehicles) × (average inter-vehicle distance + average vehicle length)”. Further, in the present embodiment, the number of passing vehicles is accumulated by the main controller, but may be accumulated by each passing vehicle measuring device.

As described above, according to the present embodiment, the vehicles 28 passing through the points P and Q in the direction A are detected using the passing number measuring devices 32P and 32Q, and the vehicles 28 are detected at predetermined time intervals. The number of vehicles passing is monitored to monitor traffic congestion. If the P point and the Q point are separated by, for example, 1 km and a wide area of traffic jam is detected, the vehicle or the store 2 that turns toward the fork 26 between the P point and the Q point
The error increases depending on the vehicle or the like entering the position 9. However, when detecting traffic congestion in a narrow area where the distance between the point P and the point Q is, for example, 100 m, the influence of the vehicle entering the branch road 26, the store 29, or the like is extremely small, and the traffic congestion state can be accurately determined. Can be detected. Moreover, since the traffic flow monitoring device only needs to be a sensor capable of counting the number of passing vehicles, the system is simpler and the cost is lower than in the second embodiment that performs image processing. In addition, the number of vehicles on standby is calculated from the difference between the total number of vehicles passing at each of the two points to determine the congestion time, so that the congestion state can be easily grasped. Further, a traffic light 7A is installed near the passing traffic number measuring device 32Q on the downstream side, and if the passing vehicle is interrupted before the blue time T1A of the traffic light 7A elapses, it is determined that there is no traffic congestion, and the point P Since the total number of vehicles passing through the points Q and Q is reset to zero, the influence of errors caused by vehicles entering the branch road 26, the store 29, and the like can be further reduced, and the traffic congestion state can be accurately detected.

If the number of passing vehicles exceeds a certain level and the “number of vehicles passing per hour” at the point P and the point Q substantially match, it can be determined that the rear end of the traffic jam has reached the point P. The traffic jam time required to move between two points can be determined. In addition, since the downstream passage number measuring device 32Q is installed in a traffic flow bottleneck such as a road construction site, the base point of traffic congestion can be specified, and accurate traffic congestion information, that is, "road construction From the site, v
vm traffic jam "can be obtained. Then, traffic congestion information can be sent to traffic control centers and traffic congestion bulletin boards to inform drivers, nearby residents and construction contractors of the traffic congestion status in real time. Can be expedited.

In the second and third embodiments, the example of the one-way alternate traffic control using the traffic light in the first embodiment has been described as the road construction site 10, but the present invention is not limited to this.
The present invention can also be applied to a case where the number of lanes on a road having two or more lanes on one side is reduced, or only the lane width is reduced without decreasing the number of lanes. That is, one of the traffic flow monitoring devices is installed in a bottleneck of the traffic flow as described above, and the other traffic flow monitoring device is installed at a predetermined distance away from the upstream side,
The traffic time may be monitored by measuring the travel time or the number of vehicles passing.

The data collected by the traffic control center is as follows:
The information is transmitted to the vehicle-mounted terminal of the navigation system of the automobile together with the construction position, traffic information (presence or absence of traffic, traffic time or traffic distance), and codes attached to each road going up and down. For transmission, FM multiplex broadcasting or a radio beacon provided on a main road is used. A radio beacon may be provided temporarily near the construction site. For each vehicle, to display the construction site position and the vehicle position on the same map,
It is possible to know the distance to the end of the traffic jam specifically.

As described in the embodiment, the traffic congestion information is also transmitted to the traffic congestion information board via the wireless LAN. As an example of the display contents of the congestion public information board, if the congestion time is 0, only the message “Under construction (right turn)” is displayed, and the congestion time is 0.
In other cases, "Construction traffic ahead (right turn), zzzm up to construction signal, traffic congestion time ww minutes" or "Congestion construction ahead (right turn), traffic xxm, end of traffic congestion yy"
m ”or“ Construction traffic ahead (right turn), traffic congestion xx
m, zzzm up to the construction signal, etc. are displayed. Residents near the traffic jam information board can know the size of the traffic jam when passing through, and if there is a business in the middle of the store, judge whether the store can be caught in the traffic jam can do. Alternatively, it is possible to determine what route to follow without getting caught in traffic. A GPS surveying device is provided in the traffic congestion information board, construction traffic light or traffic flow monitoring device. For example, even if the construction traffic light is moved due to the progress of construction, the distance between the roads is automatically determined. It is calculated and reflected on the display on the traffic jam publicity board. The display contents of the traffic congestion information board can be changed from the main controller at the construction site using a wireless LAN. For example, a construction start time, a construction period, and the like may be displayed. Also, it may be displayed graphically together with the shape of the road.

The state of traffic congestion is counted daily for each time slot, both up and down, and stored in a database. Depending on the situation of traffic jams, measures such as adding a traffic jam public information board may be taken. In the embodiment, the road construction site has been described as an example, but the present invention is similarly applied to not only road construction but also a case where a part of the road is temporarily closed due to a traffic accident, a disaster or the like. .

As the traffic flow monitoring apparatus, the apparatus using the millimeter wave has been described in the first and third embodiments. However, the presence or absence of the vehicle, the speed, etc. are determined by light processing such as a laser wave or image processing using a television camera. May be detected. It is needless to say that the numerical values and expressions used in the embodiment are not limited to these, and can be set arbitrarily according to the conditions at the construction site.

[Brief description of the drawings]

FIG. 1 is a diagram showing an installation state of a traffic jam monitoring system according to a first embodiment.

FIG. 2 is a system block diagram of a traffic jam monitoring system according to the first embodiment.

FIG. 3 is a structural diagram of a vehicle detection device.

FIG. 4 is a flowchart showing an outline of a procedure of the traffic congestion monitoring system.

FIG. 5 is a flowchart of an all stop mode.

FIG. 6 is a flowchart of a pass mode.

FIG. 7 is a flowchart of a congestion determination mode.

FIG. 8 is a flowchart of a blue time setting mode.

FIG. 9 is a diagram illustrating an installation state of a traffic jam monitoring system according to a second embodiment.

FIG. 10 is a system block diagram of a traffic jam monitoring system according to a second embodiment.

FIG. 11 is a flowchart of congestion monitoring by vehicle discrimination.

FIG. 12 is a diagram illustrating an installation state of a traffic jam monitoring system according to a third embodiment.

FIG. 13 is a system block diagram of a traffic jam monitoring system according to a third embodiment.

FIG. 14 is a flowchart of congestion monitoring by measuring the number of passing vehicles.

[Explanation of symbols]

1 ... 2 lane road, 2 ... Alternate traffic section, 3A, 3B, 3C
... Entrance, 7A, 7B, 7C ... traffic light, 10 ... construction section, 11A, 11B, 11C ... approach section, 12 ... vehicle detection device, 13 ... approaching vehicle, 14, 24, 34 ... main controller, 22P, 22Q ... vehicle Discrimination device, 23: passing vehicle, 27: traffic jam information board, 28: vehicle, 32P, 32
Q: Passing number measuring device.

Claims (7)

[Claims] 1. A vehicle having a plurality of approach roads entering one lane of a road, wherein vehicles in different traffic directions alternately pass through said one lane at predetermined permission time intervals. A traffic signal provided, a vehicle detection device for detecting the presence or absence of a vehicle passing through the alternating traffic section, and a display controlling the traffic signal to control a direction in which the vehicle is allowed to enter the alternating traffic section and to pass through the alternating traffic section. It is determined whether the vehicle in the entry permission direction detected by the vehicle detection device continuously passes through the passage permission time or not, and the event of the continuous passage occurs continuously for each passage permission in the same entry direction. A congestion monitoring system, comprising: a controller that determines that congestion has occurred when the traffic jam has occurred. 2. The traffic congestion monitoring system according to claim 1, wherein the vehicle detection device measures a distance to a vehicle. 3. A first vehicle discriminating device provided at a first point near a road construction site on an upstream side in a traffic direction for monitoring traffic congestion at a road construction site, and detecting a characteristic of a passing vehicle and discriminating the vehicle. A second vehicle discriminating device provided at a second point on the upstream side of the road construction site and separated by a predetermined distance from the first point and detecting a characteristic of a passing vehicle to discriminate the vehicle; The travel time of the vehicle from the second point to the first point when the vehicle detected by the first vehicle discriminating device is detected by the first vehicle discriminating device; A control device that determines a traffic jam time, which is a difference between the travel time and the normal travel time, from the normal travel time to the point, and determines a traffic jam situation based on the road construction site based on the determined traffic jam time. Traffic congestion monitoring system. 4. The traffic congestion monitoring system according to claim 3, wherein the road construction site has a plurality of approach roads entering one lane of the road, and vehicles in different traffic directions alternate with the one lane at predetermined permission times. A traffic signal indicating an approach permission direction to the alternating traffic section at the first point, and the control device changes an entry permission direction to the alternating traffic section by switching a display of the traffic light. Traffic congestion monitoring, wherein, when the vehicle detected by the first vehicle discriminating device does not continuously pass, the travel time at that time is updated as a normal travel time. system. 5. A first passage number measuring means provided at a first point near a road construction site on an upstream side in a traffic direction for monitoring traffic congestion at a road construction site, and measuring presence and absence of vehicles passing therethrough. A second passing number measuring means provided at a second point on the upstream side of the road construction site and separated by a predetermined distance from the first point and measuring the presence and the number of vehicles passing therethrough; First accumulating means for calculating the number of passing vehicles based on the data measured by the means, second accumulating means for calculating the number of passing vehicles based on the data measured by the second passing number measuring means, From the cumulative number of vehicles passing through the second point accumulated by the accumulating means and the cumulative number of vehicles passing through the first point accumulated by the first accumulating means, the difference between the two is calculated to obtain the number of waiting vehicles. The road construction site is used as the base point based on the number of waiting vehicles. Congestion monitoring system characterized by comprising a controller for determining the status of the traffic jam that. 6. The traffic congestion monitoring system according to claim 5, wherein the road construction site has a plurality of approach roads entering one lane of the road, and vehicles in different traffic directions alternate with the one lane at predetermined permission times. A traffic signal indicating an approach permission direction to the alternating traffic section at the first point, and the control device changes an entry permission direction to the alternating traffic section by switching a display of the traffic light. When the vehicle is detected and the vehicle detected by the first vehicle discriminating device does not continuously pass, the cumulative number of vehicles passing through the first point and the cumulative number of vehicles passing through the second point are updated to zero. Traffic congestion monitoring system. 7. The traffic congestion monitoring system according to claim 3, further comprising a traffic congestion bulletin board upstream of the second point, wherein the control device is configured to control a distance of the traffic congestion based on the first point. When,
A congestion monitoring system characterized in that a distance between a first point and a congestion information board or a distance between an end of congestion and a congestion information board is displayed on the congestion information board.