JP2001084486A - Traffic signal control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a traffic signal control system capable of properly resolving a traffic jam on a main line, which is caused by vehicles turning right, in accordance with the traffic volume. SOLUTION: The traffic signal control system is provided with an entrance side detector 7 which is installed at an upstream side position apart from an intersection by a prescribed distance and detects a traffic jam, and an exit straight advance sensor 8, an exit right turning sensor 9, and an exit left turning sensor 10 which are provided on the exit straight advance side, the exit right turning side, and the exit left turning side respectively on the basis of a main track 1 and detect a traffic jam. When the entrance side sensor 7 detects the traffic jam but other sensors don't detect the traffic jam, this state is regarded as the main track jam state caused by vehicles 11a turning right, and the timing of lighting of a red signal lamp of a signal 6 is set more quickly than normal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traffic signal control system for controlling the flow of vehicles near an intersection by turning on or blinking a signal light.

[0002]

2. Description of the Related Art On an intersection, when there are many vehicles flowing in an oncoming lane opposite to the main line, a vehicle attempting to make a right turn on the main line cannot make a right turn even if there is no vehicle on the exit right turn side of the intersection. In this case, especially when there is no right-turn lane, the flow of the vehicle behind the right-turn vehicle stops. Therefore, conventionally, an arrow signal light is provided, and when the signal light for the oncoming lane turns red, the arrow signal light for the main line is turned on so that the right-turn vehicle can make a right turn, or the signal light lighting timing for the oncoming lane After setting the time difference between the traffic light lighting timing for the main lane and the red traffic light for the oncoming lane, the blue traffic light for the main lane is kept for a while so that the right-turn vehicle can turn right smoothly. ing.

[0003] However, such a traffic light cannot perform optimal control according to the number of vehicles because the lighting timing and the time difference of the arrow signal light are fixed.

To solve this problem, there is a traffic light control system disclosed in Japanese Patent Application Laid-Open No. Sho 62-46400. In this system, a sensor that detects a vehicle is placed at the intersection entrance of the main line, and if the sensor detects a vehicle when the main signal light changes from blue to red, the lighting time of the blue signal light is extended for a certain time. Thus, when there is a right-turn vehicle, the vehicle can smoothly turn right.

[0005]

However, in the above traffic signal control system, since a sensor is provided at the intersection of the main line, it is necessary to determine whether there is a congested vehicle behind the vehicle detected by this sensor. Not be able to
Also, since the leading vehicle is not necessarily a right-turn vehicle, it is not possible to eliminate the situation in which many vehicles are congested behind this right-turn vehicle due to the right-turn vehicle on the main line. there were.

An object of the present invention is to provide a traffic signal control system capable of appropriately eliminating traffic congestion on a main line caused by a right-turn vehicle according to the traffic volume at that time.

[0007]

The present invention has the following arrangement to solve the above-mentioned problems.

(1) A traffic signal controller for controlling the flow of vehicles near an intersection by turning on or off a signal light, and detecting the presence or absence of traffic congestion of a vehicle provided at a predetermined distance upstream of the intersection on the main line. An entrance sensor that detects the presence of traffic congestion on the main line, an exit straight detector on the main line that detects the presence or absence of traffic congestion, and a vehicle that is provided on the right turn side of the intersection based on the main line. An exit right turn side sensor for detecting, and an exit left turn side sensor provided on the exit left turn side of the intersection on the basis of the main line, for detecting the presence or absence of traffic congestion of the vehicle, the traffic signal control unit includes an entrance side sensor Detects traffic congestion and restricts vehicles from the oncoming lane from entering the intersection when the exit straight detector, exit right turn detector, and exit left detector do not detect vehicle congestion, respectively. From the main line Turn right to perform the lighting control of the signal lights as possible.

In the present invention, a sensor is provided on each exit side of the intersection, but on the main line, the sensor is provided at a position away from the intersection by a predetermined distance upstream. Here, the main lane means a lane that is currently used as a reference. A lane facing the main lane is called an oncoming lane, a right turn lane is called a right turn lane, and a left turn lane is called a left turn lane. Further, the position where the entrance-side sensor is provided is a position which is away from the intersection by a predetermined distance upstream, and this predetermined distance is suitably set based on the average flow rate of the vehicle at the intersection. The average is about 20 to 30 m. Further, it is appropriate to install the other sensors at a position about 1 to 2 m from the intersection.

[0010] With each sensor arranged as described above,
When the following conditions (a) to (d) are satisfied, the traffic signal control unit regards the right-turning vehicle as a traffic congestion state on the main line.

(A) The entrance-side sensor detects vehicle congestion.

(B) The straight detector on the exit side has not detected vehicle congestion.

(C) The exit right-turn detector does not detect vehicle congestion.

(D) The left turn detector at the exit does not detect vehicle congestion.

The presence or absence of the detection of vehicle congestion can be determined by whether or not each sensor continuously detects one vehicle. Ultrasonic sensors, laser light sensors,
An image sensor or the like can be used. For example, a threshold value for 10 seconds is set, and when one vehicle is detected for more than this period, it is detected as being in a vehicle congestion. Also, when only a certain number or less of vehicles pass during a period of 10 seconds, it is also detected that there is traffic in the vehicle.

Under the above condition (a), it can be known that the vehicle is congested from the leading vehicle at the intersection to the entrance-side sensor. In addition, the above (b) to (d)
Under the condition (1), it can be seen that the leading vehicle is a right-turning vehicle, and the vehicle flowing on the opposite lane cannot turn right.

Therefore, when all of the above conditions are satisfied, it can be regarded as a traffic congestion state due to a right-turning vehicle. In this case, the traffic light from the oncoming traffic lane is restricted by the control of the traffic light. Then, control is performed so that the right-turn vehicle can make a right turn in the right turn lane.

(2) The traffic signal controller controls the lighting of the signal lights at the specific time, that is, when the right-turning vehicle is in a traffic congestion state, by changing a normal lighting cycle from the start of blue lighting to the extinguishing of red for each lane. Instead, only the lighting time of each color signal lamp with respect to the oncoming lane is changed.

Since the above-mentioned control operation of the traffic signal control unit is performed without changing the normal lighting cycle, the right turn is performed without affecting the signal light control of another intersection linked to the signal light control of this intersection. The traffic congestion state of the main line by the vehicle can be eliminated.

(3) The traffic signal controller turns on the yellow traffic light and the red traffic light for the oncoming lane earlier than the normal lighting timing at the specific time, that is, when the traffic congestion state of the right-turn vehicle is detected. At the timing when the red traffic light turns off and the blue traffic light turns on, the blue traffic light for the oncoming lane is also turned on at the same time.

In a traffic congestion state due to a right-turn vehicle,
Since it is necessary to restrict vehicles from the oncoming lane from entering the intersection so that the right-turning vehicle can make a right turn to the right-turning lane, the actual lighting control of the signal light is performed when the right-turning vehicle detects a traffic congestion state on the main line. It is necessary to turn on the yellow traffic light and the red traffic light for the lane earlier than the normal lighting timing. Then, control is performed such that the blue signal light for the oncoming lane is simultaneously turned on at the timing when the red signal light for the main line vehicle is turned off and the blue signal light is turned on. By such control, the lighting time of the blue traffic light for the main line vehicle is longer than the normal lighting time.

(4) When the traffic signal controller detects a traffic congestion state due to a right-turning vehicle while the main line and the oncoming lane are blinking yellow, the traffic signal control unit starts lighting control of each signal lamp in a normal lighting cycle. The yellow traffic light and the red traffic light for the oncoming lane are turned on earlier than the normal lighting timing, and the main traffic and the oncoming lane are controlled to the original yellow blinking state at the timing when the red traffic light for the main lane turns off.

The control of the above (3) is a control during a time period when the number of vehicles is large, such as during the daytime, and the signal lights are blue → yellow → red → blue →. . . . It is assumed that it changes periodically. In a time zone when the number of vehicles is small, such as at night, the signal light may blink yellow (other lanes blink red) without such a periodic change. Therefore, when such control is performed, when the traffic congestion state of the right-turn vehicle is detected, the lighting control of each signal light is started in the normal lighting cycle, and the control as described in (3) is performed. After performing the control for one cycle, the control state is returned to the control state of the yellow blinking state again.

(5) The traffic signal controller performs the control according to any one of claims 1 to 3 only when a traffic congestion state near an intersection of an oncoming lane is not detected.

If the vicinity of the intersection of the oncoming lane is congested, the above-mentioned controls (1) to (4) may rather cause confusion. Therefore, the above control is performed on the condition that there is no traffic congestion near the intersection of the oncoming lane.

[0026]

FIG. 1 is a conceptual diagram showing a traffic signal control system according to an embodiment of the present invention.

There are a main line 1, an oncoming lane 2, a right turn lane 3 and a left turn lane 4 around an intersection, and the road has two lanes.

In this case, the lane in which the vehicle flows upward in the plane of the paper is defined as the main lane 1. However, this lane is referred to as the main lane 1 for the sake of explanation. The lane becomes the main lane.

At the intersection, a traffic light 5 is arranged on the exit straight side of the main lane 1, and a traffic light 6 is arranged on the exit straight side of the oncoming lane 2. Similarly, a traffic light (not shown) is also provided at the exit right turn side of the right turn lane 3 and the exit left turn side of the left turn lane 4.
Is arranged.

Further, as a detector for detecting the presence or absence of traffic congestion of the vehicle, an exit straight detector 8 is disposed on the exit straight side of the main line 1, and 20 to 30 meters upstream from the intersection of the main line 1.
An entrance-side sensor 7 is arranged at a remote position. Also,
On the basis of the main line 1, an exit right turn side sensor 9 is disposed on the exit right turn side of the intersection, and an exit left turn side sensor 10 is disposed on the exit left turn side of the intersection.

Each of the sensors 7 to 10 is constituted by a reflection type ultrasonic sensor fixed above a road which is a lane, and when a reflection signal from a vehicle is continuously detected for a predetermined time (here, 10 seconds). Alternatively, when only about two or three vehicles pass during the certain period, it is detected that there is a vehicle congestion. In the figure, a rectangle connected to the upstream side of the leading vehicle 11a indicates a vehicle, and the entrance-side detector 7 is installed on the road away from the vehicle 11.

By arranging the detectors 7 to 10 as described above, if the leading vehicle 11a stops at an intersection while the traffic lights 5 and 6 are in the blue state, the following three causes for the stop are considered. One can be considered.

(A) There is a traffic jam on the vehicle on the exit straight side of the main line 1.

(B) There is traffic congestion on the left turn side of the main line 1.

(C) There is traffic congestion on the right turn side of the exit of the main line 1 or the right turn lane 3 cannot be turned right due to the flow of vehicles in the opposite lane 2.

On the other hand, in a state where the leading vehicle 11a is stopped at the intersection, when the entrance-side sensor 7 detects the traffic jam of the vehicle, the vehicle is moved between the leading vehicle 11a and the entrance-side sensor 7. You will be congested.

Then, the entrance side sensor 8 detects the traffic jam,
When the remaining three sensors 8, 9, and 10 do not detect traffic congestion, the leading vehicle 11a is a right-turn vehicle that is prevented from turning right by a vehicle flowing on the oncoming lane 2, and this right-turn vehicle is turned off. It can be determined that traffic congestion occurs on the upstream side of the vehicle due to the vehicle.

As described above, when the entrance-side sensor 7 detects vehicle congestion and the remaining three sensors 8, 9, and 10 do not detect vehicle congestion, it is considered that a right-turn vehicle congests the main line. Then, signal light control is performed to restrict the flow of vehicles in the oncoming lane 2 so that the right-turning vehicle (leading vehicle) 11a can make a right turn in the right-turn lane 3. That is, when the traffic congestion state due to the right turn vehicle is detected, the yellow traffic light and the red traffic light of the traffic light 6 for the oncoming lane 2 are turned on earlier than the normal lighting timing, and the leading vehicle (right turn vehicle) 1
1a enables a right turn to the right turn lane 3 smoothly. Also, at this time, the traffic light 5 for the main line vehicle 1 is lit in blue.
At the same time. This allows
Without changing the lighting cycle of one cycle of each signal light,
By substantially reducing the blue lighting time of the oncoming lane 2, the leading vehicle (right-turning vehicle) 11a can smoothly turn right into the right-turning lane 3. In the above description, it is described that only one leading vehicle 11a can make a right turn. However, after the leading vehicle 11a shown in FIG. 1 turns right, the next vehicle becomes the leading vehicle 11a. While the flow of vehicles on 2 is suppressed, all vehicles that can make a right turn can make a right turn.

As described above, the entrance-side sensor 7 is provided at a position 20 to 30 m away from the intersection with respect to the main line 1, and the sensors 8, 9, 10 and 10 are located at the exits of the vehicle with respect to the main line 1.
And detects the traffic congestion state of the right-turn vehicle based on the result of the traffic congestion detection by the sensor, and controls the lighting of the signal lights for the oncoming lane.

FIG. 2 shows a state in which the leading vehicle (right-turning vehicle) 11a is able to turn right into the right-turning lane 3 as a result of detecting the traffic congestion state of the right-turning vehicle and controlling the turning on of the signal light for the oncoming lane 2. I have. 1 of the leading vehicle 11a on the main line 1
When the platform turns right, the entrance-side detector 7 may not detect traffic congestion, but the lighting state of the red traffic light of the traffic light 6 for the oncoming lane 2 is maintained. The detectors 8, 9, 1
The position of 0 is suitably a position about 1 m away from the intersection. In this example, the position of the entrance-side sensor 7 is set at the upstream side 20 to 30 m away from the intersection in this example.
This length is set to an appropriate value based on the total number of vehicles flowing into the intersection, the average number per hour, and the like.

When the above control is performed in each lane, it is necessary to separately install the entrance-side sensors 7 at positions 20 to 30 m upstream of the intersection for each lane. .

FIG. 3 is a block diagram of the traffic signal control system. Each of the detectors 7 to 10 is a main line congestion state detection unit 2
0, and when a traffic congestion state on the main line is detected, a detection signal is input to the signal light lighting control unit 21. In the normal state (when the main line congestion state detection signal is not received), the signal light lighting control unit 21 performs on / off control of each signal light based on a preset normal light timing of each signal light. When it is received, the lighting control of each color signal light with respect to the oncoming lane is performed based on the preset lighting timing of each signal light in a traffic jam.

FIG. 4 shows the normal lighting timing and the traffic jam lighting timing, respectively. FIG. 4A shows the normal lighting timing, and the lighting timing of each of the blue, yellow, and red signal lights in each lane is illustrated. Note that T is the normal lighting cycle, and this cycle is not changed at the normal lighting timing or the traffic jam lighting timing.

At the traffic jam lighting timing shown in FIG. 4B, when a traffic congestion state due to a right-turn vehicle is detected, the blue traffic light for the oncoming lane is turned off, and the red traffic light is turned on after turning on the yellow light. As a result, on the main line 1, the right-turning vehicle can make a right turn during the time TA from when the red traffic light for the oncoming lane is turned on to when the red traffic light for the main traffic is turned on. When the red signal light for the main line 1 goes out and the normal lighting cycle ends, the red signal light for the oncoming lane also goes out, and at the start of the next lighting cycle, both the main line 1 and the oncoming lane 2 start to light up at the same time.

In the lighting timing at the time of congestion in FIG. 4B, the period of TA changes according to the congestion state of the vehicle. As a result, signal light control for an appropriate oncoming lane according to the traffic jam at that time is performed.

FIG. 5 is a flowchart showing the control operation of the signal lamp lighting control section 21.

At the start timing of the normal lighting cycle, that is, when the red signal light is turned off and the blue signal light is started to be turned on at the traffic light 5 for the main line 1, the operation after ST1 is performed. In ST1, an inquiry is made to the main line traffic congestion state detection unit 20 as to whether or not there is a main line traffic congestion state due to a right turn vehicle. If the main line is not in a traffic congestion state, the process proceeds to ST2, in which a normal lighting timing is input, and signal light control is performed (ST4). If the main line is in a congested state, the process proceeds to ST3, in which a lighting timing at the time of congestion is input to perform signal light control.

FIG. 6 shows a schematic operation of the traffic congestion state detecting section 20 of the main line. The detector 20 constantly monitors each of the sensors 7 to 10 (here, represented by S1 to S4). In ST10, the sensor outputs of S1 to S4 are input, and in ST11 to ST14, it is determined whether or not there is a traffic congestion state due to a right-turn vehicle. That is, S1
It is determined whether or not the (inlet side sensor 7) maintains the ON signal continuously for 10 seconds or more, and in each of ST12 to ST14, S2 (outlet straight side sensor 8), S3
(Exit right turn side sensor 9), S4 (Exit left turn side sensor 1)
0) is continuously detected for 10 seconds or more. If the condition of ST11 is satisfied and the condition of each step is not satisfied in any of ST12 to ST14, the process proceeds to ST16, and it is determined that there is a traffic jam. Otherwise, the process proceeds to ST15, where it is determined that there is no congestion. In this example, it is detected whether the ON signal is continuously maintained for 10 seconds or more. However, a predetermined number of vehicles or less (for example, 2 to 3
(Vehicles or less) may be detected as congested.

FIG. 7 shows another embodiment of the present invention. In this example, the normal lighting timing at night and the lighting timing at traffic congestion are shown. That is, FIG. 7A shows normal lighting timing at night, and both the main lane 1 and the oncoming lane 2 are in a blinking yellow state. Although the lighting timing of the signal lights for the right turn lane 3 and the left turn lane 4 is not shown in the drawing, the red light blinks at night.

When the traffic congestion state of the main line by the right-turning vehicle is detected at the nighttime normal lighting timing of (A), the lighting control of the signal lamp is performed from that time by the nighttime congestion lighting timing of FIG. 7B. In this control, both the oncoming traffic lane and the oncoming traffic lane start from the start of lighting of the blue traffic light, and in the traffic light control for the oncoming traffic lane, the lighting start timing of the yellow traffic light and the red traffic light is made earlier than the lighting start timing of the traffic light for the main traffic lane. . When the normal lighting period T ends, the process returns to the lighting control based on the nighttime normal lighting timing in FIG. Note that, in this example, after the normal traffic cycle T has elapsed since the detection of the traffic congestion state of the main line by the right-turning vehicle, the control returns to the control of the normal night lighting timing by blinking yellow in FIG. In this case, since the repetition cycle of the normal lighting cycle T is shifted, the lighting control is returned to the blinking yellow in FIG. 7A at the end timing t0 of the first cycle so that the cycle T is not shifted. You may do so.

FIG. 8 shows a flow of still another embodiment. The difference between this example and the example shown in FIG. 5 is that when the signals of the main lane and the oncoming lane change from red to blue and the normal lighting cycle starts, first, it is determined whether there is congestion near the intersection of the oncoming lane. The point to check. If there is congestion, Figure 5
Directly goes to the process of ST2, and performs signal lamp control at the normal lighting timing. If a traffic jam near the intersection of the oncoming lane is detected in ST5, the process proceeds to ST1 and the subsequent steps in FIG. In addition,
Normally, since the entrance side sensor is also provided in the oncoming lane,
The presence or absence of traffic congestion near the intersection of the oncoming lane is detected by this entrance side sensor.

[0052]

According to the present invention, traffic congestion near an intersection caused by a vehicle trying to make a right turn can be eliminated by optimal signal light control according to the traffic volume at that time. It can respond flexibly to traffic jams. The present invention is also effective at intersections of roads where a lane dedicated to right turns cannot be physically taken. The present invention is also effective for an intersection where there are many straight-ahead vehicles, but where it is not desired to install a right arrow signal or perform time difference control.

Furthermore, since the normal lighting cycle is not changed, the control is simplified, and there is no need to consider the relation with other linked traffic signal control systems.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a traffic light control system according to an embodiment of the present invention.

FIG. 2 is a diagram showing the movement of a vehicle in the system.

FIG. 3 is a configuration diagram of the system.

FIG. 4 is a diagram showing a normal lighting timing and a lighting timing in a traffic jam.

FIG. 5 is a flowchart showing the operation of the signal light lighting control unit.

FIG. 6 is a flowchart showing the operation of a traffic congestion state detection unit on the main line;

FIG. 7 is a diagram showing a normal lighting timing and a congestion lighting timing according to another embodiment of the present invention.

FIG. 8 is a part of a flowchart showing the operation of still another embodiment of the present invention.

[Explanation of symbols]

 1-main line 2-oncoming lane 3-right turn lane 4-left turn lane 7-entrance sensor 8-exit straight detector 9-exit right turn sensor 10-exit left turn sensor 11-vehicle 11a-head Vehicle (right turn vehicle)

Claims (5)

[Claims] 1. A traffic signal control unit for controlling the flow of vehicles near an intersection by turning on or blinking a signal light, and detecting the presence or absence of traffic congestion of a vehicle provided at a predetermined distance upstream from the intersection on the main line. Entrance-side sensor, Exit straight-side sensor provided on the main line at the exit straight ahead of the intersection, and Detects the presence of vehicle congestion at the intersection right turn exit based on the main line. Exit right turn side sensor to be provided, and an exit left turn side sensor provided on the exit left turn side of the intersection on the basis of the main line to detect the presence or absence of traffic congestion of the vehicle, wherein the traffic signal control unit comprises: Detects vehicle congestion, and restricts vehicles from the oncoming lane from entering the intersection when the exit straight detector, exit right turn detector, and exit left detector do not detect vehicle congestion, respectively. From the main line A traffic signal control system characterized by controlling lighting of signal lights so that a right turn can be made. 2. The traffic signal control unit controls the lighting of the signal light at the specific time by changing the lighting time of each color signal light on the oncoming lane without changing the normal lighting cycle from the start of blue lighting on each lane to the turning off of red light. The traffic signal control system according to claim 1, wherein only the traffic light is changed. 3. The traffic signal control unit turns on the yellow traffic light and the red traffic light for the oncoming lane earlier than the normal lighting timing at the specific time, and turns off the red traffic light for the main lane vehicle at the timing when the blue traffic light is turned on. The traffic signal control system according to claim 2, wherein the traffic light control system controls so that a blue traffic light for a lane is also turned on at the same time. 4. The traffic signal control unit, when detecting the traffic congestion state of a right-turn vehicle while the main line and the oncoming lane are blinking yellow, starts lighting control of each signal light in a normal lighting cycle, and The traffic signal control system according to claim 3, wherein the yellow traffic light and the red traffic light for the lane are turned on earlier than the normal lighting timing, and the main traffic lane and the oncoming lane are controlled to the original yellow blinking state at the timing when the red traffic light for the main lane turns off. . 5. The traffic signal control system according to claim 1, wherein the traffic signal control unit performs the control according to any one of claims 1 to 4 only when a traffic congestion state near an oncoming lane intersection is not detected.