JP2008059615A - Traffic signal controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a traffic signal controller to suppress an unnecessary green light time period at a road having no oversaturation when one of a main road and a subordinate road at an important intersection is oversaturated while the other is not, and to properly control a signal lamp according to the traffic condition of an inflow link. <P>SOLUTION: The signal control unit 1 decides whether the inflow link of a predetermined bottleneck intersection B in a segment is oversaturated or not. When determined that the inflow link of the intersection B is oversaturated, the unit 1 simulates a change in traffic conditions in the inflow link of the important intersection up to a predetermined time period for each of a plurality of signal control parameter candidates. A signal control parameter candidate having minimum time difference of eliminating the oversaturation in the main and subordinate roads is decided as a signal control parameter for controlling the signal lamp of the intersection. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a signal control device for controlling a signal lamp installed at each intersection in a segment.

  Conventionally, a predictive signal control device that controls a signal lamp installed at an intersection has been proposed (see Patent Documents 1 and 2). The predictive signal control device generates vehicle arrival prediction information at the intersection based on vehicle passage information upstream of the inflow link detected by a vehicle detector installed upstream of the inflow link at the intersection. For example, time series information indicating the number of vehicles that have passed the sensing position of the vehicle detector is generated every n seconds, and this time series information is shifted by the travel time of the vehicle from the sensing position of the vehicle detector to the intersection. The vehicle arrival prediction information at the intersection is generated. Further, the predictive signal control apparatus generates a plurality of signal control parameter proposals. Then, for each of the proposed signal control parameters, the traffic condition at the intersection is simulated using the arrival prediction information, and evaluation indexes such as the green time utilization rate and the number of stops are calculated. The signal control device determines the signal control parameter plan for which the evaluation index calculated here is optimum as the signal control parameter for controlling the signal lamp installed at the intersection, and is installed at the intersection with this signal control parameter. Control the signal lights.

The signal control parameters for controlling the signal lamp are cycle, split, and offset as is well known. The cycle is the time of one period of the signal lamp, the split is the ratio of the blue time in one cycle, the offset is the difference in cycle start timing between the intersections (relative offset), or the difference in cycle start timing from the reference intersection (Absolute offset). A segment (sometimes called a sub-area) is a group of intersections with similar traffic conditions, and is a unit for operating signal lamps with a common cycle length. The pattern selection control is a general method as traffic signal control in Japan, and is a method of selecting one corresponding to traffic demand observed by a vehicle sensor from a plurality of preset signal control parameters. The vehicle detector uses an image type that senses the vehicle by processing an image captured by the CCD camera, an ultrasonic type that senses the vehicle by an ultrasonic sensor, an optical type that senses the vehicle by an optical sensor, and the like. Yes.
Japanese Patent No. 3380882 JP 2002-245586 A

  By the way, the preferable control of the signal lamp is a control in which the number of vehicles that stop at the intersection is suppressed, and the vehicles that have arrived at the intersection are smoothly discharged downstream.

  However, when one of the inflow links is in a supersaturated state where traffic is congested, it is impossible to control the signal lamp that smoothly flows out the vehicle arriving at the intersection downstream. Specifically, in order to reduce the number of vehicles that stop at the intersection for the inflow link of the oversaturated main road (in order to smoothly flow out vehicles that arrive at the intersection downstream) Increasing the (blue hour) inevitably shortens the split on the secondary road side. As a result, the number of vehicles that stop at the intersection on the side of the secondary road increases, which greatly hinders the travel of the vehicle on the secondary road, and the secondary road side vehicle does not flow smoothly downstream. In addition, the inflow links on both the main road side and the secondary road side may be oversaturated at the same time. In such a case, if priority is given to the travel of the vehicles on the main road side, the congestion on the side of the secondary road will be extended, and the number of vehicles stopping at the intersection on the side of the secondary road will be extremely increased. As a result, it took a long time for all the inflow links at the intersection to become unsaturated and not congested.

  On the other hand, when the oversaturated state of the inflow link is resolved, the vehicle travels smoothly on the main road and the secondary road, the number of vehicles that stop at the intersection is suppressed, and the vehicle that arrives at the intersection smoothly goes downstream. It will be leaked. Therefore, when the inflow link is oversaturated, it is appropriate to control the signal lamp so as to minimize the time until the oversaturated state is eliminated. However, the conventional signal control device controls such a signal lamp. There was a problem that I could not.

  The object of the present invention is to control an appropriate signal lamp according to the traffic situation at the time of traffic situation of an inflowing link at an important intersection, whether it is supersaturated or non-saturated. It is an object of the present invention to provide a signal control device capable of suppressing a wasteful green time on a road side in which a supersaturated state is eliminated, which occurs when one of the secondary roads is oversaturated and the other is oversaturated.

  The signal control device of the present invention has the following configuration in order to solve the above problems.

(1) In a signal control apparatus for determining a signal control parameter for controlling a signal lamp installed at an intersection in a segment,
Supersaturation determination means for determining whether an inflow link at a predetermined important intersection is supersaturated or nonsaturated;
When the oversaturation determination means determines that the state is oversaturated, the traffic situation on the inflow link at the important intersection is predicted for a predetermined time for each of a plurality of proposed signal control parameters, and the evaluation index for the prediction result is optimal. Supersaturated signal control parameter determining means for determining the proposed signal control parameter as a signal control parameter for controlling the signal lamp installed at the important intersection,
The above-described supersaturated signal control parameter determining means is a signal control parameter that minimizes the time difference of oversaturated state cancellation between the main road and the secondary road at an important intersection when a prediction result that the supersaturated state is resolved by a predetermined time is obtained. The plan is determined as a signal control parameter for controlling a signal lamp installed at an important intersection.

  In this configuration, the supersaturation determination means determines whether the inflow link at a predetermined important intersection in the segment is in a supersaturated state or a nonsaturated state. An important intersection is an intersection where a main road and a secondary road with a relatively high traffic volume intersect. When traffic congestion occurs in a segment, the inflow link is very likely to be oversaturated. is there. In other words, by determining whether the inflow link at the important intersection is in a non-saturated state or a super-saturated state, it is possible to determine whether or not there is congestion in the segment.

  When it is determined by the oversaturation determination means that the inflow link at the important intersection is oversaturated, the oversaturation signal control parameter determination means determines a signal control parameter for controlling the signal lamp installed at the important intersection. For example, for each of a plurality of proposed signal control parameters, a change in the traffic situation is simulated until a certain time ahead for the traffic situation on the inflow link at the important intersection. Then, the signal control parameter plan that takes the shortest time to eliminate the oversaturated state of the inflow link at the important intersection is determined as the signal control parameter for controlling the signal lamp at the important intersection. Therefore, when the inflow link of the important intersection is in a supersaturated state, it is possible to appropriately control the signal lamp that can eliminate this supersaturated state as early as possible.

  In addition, since the signal control parameter with the shortest time difference at which the supersaturated state between the main road and the secondary road is resolved is determined, when either the main road or the secondary road is oversaturated and the other is oversaturated. The wasteful green time on the road side where the oversaturated state is eliminated can be suppressed.

(2) With respect to the inflow links at the important intersections, a remaining remaining number detecting means for detecting whether or not the remaining number of surpluses exceeds a predetermined number,
The oversaturation determining means determines that the inflow link at the important intersection is in a supersaturated state when the remaining remaining number detected by the remaining remaining number detecting means exceeds a predetermined number.

  In this configuration, the number of vehicles remaining on the inflow link at the important intersection without passing through the important intersection during the green light and outflowing to the inflow link at the downstream intersection, that is, the number of remaining cars is predetermined. When the value exceeds, it is determined that the inside of the segment is supersaturated.

(3) A blue hour utilization rate detecting means for detecting a blue hour utilization rate is provided for the inflow link at the important intersection.
In the oversaturation determination means, the remaining number of remaining detected by the remaining remaining number detecting means exceeds a predetermined number, and the blue hour utilization rate detected by the blue hour utilization rate detecting means is predetermined. When the predetermined value is exceeded, it is determined that the inflow link at the important intersection is supersaturated.

  In this configuration, since the blue hour utilization rate detected by the blue hour utilization rate detection unit and the number of remaining profits are determined, it is determined whether the inflow link at the important intersection is oversaturated or non-saturated. It is possible to prevent erroneous determination that an inflow link at an important intersection is in a supersaturated state when the number of remaining remaining items increases due to a deviation in offset from a signal lamp at an adjacent intersection.

(4) comprising stop vehicle detection means for detecting a stop of the vehicle at a predetermined position upstream of the important intersection at the stop line;
The oversaturation determination means is configured to stop the vehicle at a predetermined position upstream of the stop line within a predetermined time after a signal lamp installed at the important intersection is switched to a red signal. Is detected, the inflow link at the important intersection is determined to be supersaturated.

  In this configuration, whether the inflow link of the important intersection is oversaturated due to the arrival of the stop wave of the vehicle at a predetermined position upstream of the stop line of the important intersection, that is, the timing when the vehicle stops at a predetermined position upstream of the stop line of the important intersection. Determine if.

(5) a demand value calculating means for calculating a demand value indicating the traffic situation in the segment;
The supersaturation determination means determines that the inflow link at the important intersection is in a supersaturated state when the demand value calculated by the demand value calculation means exceeds a predetermined value.

  In this configuration, the demand value in the segment is calculated, and it is determined whether the inflow link at the important intersection is supersaturated based on the demand value calculated here.

  (6) When it is determined that the supersaturation determination means is in a non-saturated state, vehicle arrival prediction information at the important intersection is generated, and installed at the important intersection based on the arrival prediction information generated here. Non-saturated signal control parameter determining means for determining a signal control parameter for controlling the signal lamp is provided.

  In this configuration, when the oversaturation determination means determines that the inflow link at the important intersection is not oversaturated and is not saturated, the nonsaturation signal control parameter determination means controls the signal lamp installed at the important intersection. Determine signal control parameters. The non-saturated signal control parameter determining means generates vehicle arrival prediction information at an important intersection. This arrival prediction information is generated based on, for example, detection information of a passing vehicle detected by a vehicle detector installed upstream of an inflow link at an important intersection. Thereby, when the inflow link of the important intersection is in a non-saturated state, it is possible to control an appropriate signal lamp that allows the vehicle to smoothly flow out downstream from the important intersection.

  Therefore, even if the inflow link at the important intersection is in a supersaturated state or a non-saturated state, it is possible to appropriately control the signal lamp according to the state at that time.

  (7) The supersaturation signal control parameter determining means determines a common cycle for each intersection including the important intersection based on traffic conditions in the segment, and offsets for each intersection based on the cycle determined here. And a function for generating a plurality of proposed signal control parameters with different splits at offsets, for each of the plurality of signal control parameter proposals generated here. The traffic situation on the inflow link of the important intersection is predicted until a predetermined time, and the split of the important intersection is determined.

  In this configuration, the supersaturation signal control parameter determining means determines a common cycle for each intersection including the important intersection based on the traffic situation in the segment. A common cycle for each intersection including the important intersection is determined based on, for example, a demand value indicating a traffic situation in the segment. Also, an offset is determined for each intersection based on this common cycle. The offset is determined, for example, by pattern selection control in which offsets are registered for a plurality of cycle lengths for each intersection and an offset corresponding to the previously determined cycle is selected. A plurality of signal control parameter proposals for important intersections that differ only in the split at the cycle and offset determined in this way are generated, and for each of these signal control parameter proposals, the traffic situation on the inflow link at the important intersection is constant. Predict until the time ahead and determine the split at the important intersection.

  (8) The supersaturation signal control parameter determining means determines a split for each general intersection other than the important intersection in the segment based on a common cycle determined based on the traffic situation in the segment.

  In this configuration, the supersaturation signal control parameter determination means determines the split based on the previously determined common cycle for general intersections other than important intersections in the segment. For example, the split is determined for each general intersection by pattern selection control.

  (9) The supersaturation signal control parameter determination means estimates the number of vehicles flowing from the upstream intersection with respect to the inflow link of the important intersection by using a branching rate determined in advance for this intersection. Predict changes in the number of vehicles staying at the inflow link at the intersection.

  In this configuration, since the number of vehicles flowing into the inflow link at the important intersection from the upstream intersection is predicted using the branching rate, the traffic situation at the inflow link at the important intersection can be predicted with higher accuracy.

  (10) The supersaturated signal control parameter determining means determines, based on the prediction results for each of the plurality of signal control parameter plans, a maximum travel time, a supersaturated elimination time difference, or a total delay time on the main road and the secondary road at the important intersection. Calculated as an evaluation index, a signal control parameter for controlling a signal lamp installed at an important intersection is determined based on the calculated evaluation index.

  In this configuration, the signal control parameters are determined using the maximum travel time between the main road and the secondary road at an important intersection, the difference in oversaturated state cancellation time, or the total delay time as an evaluation index, so the secondary road and the main road are equally distributed. Or priority control on one side.

  (11) As a control target used when the supersaturated signal control parameter determination means determines a signal control parameter for controlling a signal lamp installed at an important intersection, the maximum travel time on the main road and the secondary road at the important intersection Is provided with control target designation means for designating any of equalization (so-called equality control), minimization of the maximum travel time of the main road (so-called priority control), or minimization of the total delay time.

  In this configuration, it is possible to specify a control target to be used when determining the signal control parameter, so that the traffic controller can easily change the control target in accordance with a policy viewpoint or a change in traffic conditions.

  According to the present invention, if the inflow link at the important intersection in the segment is oversaturated, it is possible to control the appropriate signal lamp to shorten the time required until the oversaturated state is eliminated. If it is non-saturated, it is possible to control the appropriate signal lights that make the vehicle run smoothly at the intersection, so the inflow link at the important intersection in the segment is either over-saturated or non-saturated. Therefore, it is possible to appropriately control the signal lamp according to the state at that time. In addition, since the signal control parameter with the shortest time difference at which the supersaturated state between the main road and the secondary road is resolved is determined, when either the main road or the secondary road is oversaturated and the other is oversaturated. The wasteful green time on the road side where the oversaturated state is eliminated can be suppressed.

  Hereinafter, a signal control apparatus according to an embodiment of the present invention will be described.

  FIG. 1 is a diagram showing a configuration of a signal control system to which a signal control apparatus according to an embodiment of the present invention is applied. In FIG. 1, reference numeral 1 denotes a signal control apparatus according to an embodiment of the present invention, and a signal control parameter for controlling a signal lamp 3 installed at each of intersections A, B, C, and D in a segment that is a control target area. To decide. The signal lamps 3 installed at the intersections A, B, C, and D in the segment are controlled with a common cycle length in order to perform system control. In other words, the signal control apparatus 1 calculates the target offset based on the common cycle length when determining the signal control parameters of the respective intersections A, B, C, and D, and the cycle of each intersection so as to become the target offset. Determine the length. In FIG. 1, the road extending in the horizontal direction is a main road, and the road extending in the vertical direction is a secondary road. The main road and the secondary road are roads having opposite lanes, and there are four inflow links at each of the intersections A, B, C, and D. Further, the intersection B is a bottleneck intersection (important intersection), and the intersections A, C, and D are general intersections that are not bottlenecks. The bottleneck intersection B is an intersection where the main road intersects with a relatively high-volume secondary road. When traffic congestion occurs in a segment, one of the inflow links is often oversaturated. It is a busy (congested) intersection. In other words, if any of the four inflow links at the intersection B of the bottleneck is oversaturated, there is a traffic jam in the segment, and conversely, none of the four inflow links at the intersection B of the bottleneck is non- If it is saturated, there is no traffic jam in the segment.

  2 is a controller which controls the signal lamp 3 installed in each intersection. The controller 2 is provided for each intersection, and controls the signal lamp 3 with the signal control parameter instructed from the signal control device 1. Reference numeral 4 denotes a first vehicle sensor installed upstream of the inflow link at each intersection (near the exit of the upstream intersection). Reference numeral 5 denotes a second vehicle detector installed on the downstream side of the inflow link at the intersection B of the bottleneck (upstream about 50 m from the intersection). Outputs of the first vehicle sensor 4 and the second vehicle sensor 5 are sent to the signal control device 1 via the controller 2.

  In addition, you may comprise so that the output of the 1st vehicle sensor 4 and the 2nd vehicle sensor 5 may be sent to the signal control apparatus 1 directly.

  The signal control device 1 processes the output (detection signal of the passing vehicle in the sensing area) for each first vehicle sensor 4 and detects the first vehicle detection every n seconds (for example, every 5 seconds) for each inflow link. The time series information indicating the number of vehicles that have passed through the sensing area of the device 4 is created, and the traveling speed of the vehicle at each inflow link is calculated. In addition, the signal control device 1 processes the output for each second vehicle sensor 5 and at each intersection B until a certain time elapses after switching to a red signal for each inflow link at the intersection B of the bottleneck. The number of vehicles that have stopped, the so-called remaining number of vehicles, is detected. The first vehicle sensor 4 and the second vehicle sensor 5 are an ultrasonic type that senses the vehicle by an ultrasonic sensor, an optical type that senses the vehicle by an optical sensor, and an image captured by a CCD camera. Any of image types for sensing a vehicle may be used.

  Further, the signal control device 1 stores the split and offset for each general intersection A, C, and D in association with the cycle length. For the important intersection B, the offset is stored in association with the cycle length. The signal control device 1 determines signal control parameters for controlling the signal lamp 3 installed at the intersection B of the bottleneck based on the outputs of the first vehicle sensor 4 and the second vehicle sensor 5. . The signal control device 1 also determines signal control parameters for the signal lamps 3 installed at the general intersections A, C, and D. The cycle of the signal lamp 3 installed at the general intersections A, C, and D is the same as the intersection B of the bottleneck. The signal control device 1 transmits the determined signal control parameters to the controllers 2 at the respective intersections A, B, C, and D in the segment. Each controller 2 controls the signal lamp 3 based on the signal control parameter sent from the signal control device 1.

  Next, the signal control apparatus 1 which is embodiment of this invention is demonstrated. The hardware configuration of the signal control device 1 according to this embodiment includes an input / output unit that inputs / outputs information to / from each controller 2, an arithmetic processing unit that processes information sent from the controller 2, and information that is used during operation. Is a general information processing apparatus that includes a storage unit that stores information generated during operation and an operation unit that performs an input operation, and the hardware configuration of such an information processing apparatus is well known, Here, illustration is omitted.

  FIG. 2 is a block diagram showing a functional configuration of the signal control apparatus according to the embodiment of the present invention. The signal control device 1 includes a sensor information processing unit 11 that processes vehicle detection signals sent from the first vehicle sensor 4 and the second vehicle sensor 5 sent via the controller 2, and a bottleneck A supersaturation determination unit 12 that determines whether or not the inflow link of the intersection B is in a supersaturated state, and a signal control parameter that controls the signal lamp 3 for each of the intersections A, B, C, and D when the segment is in a nonsaturated state A non-saturation control unit 13 that determines a signal control parameter for controlling the signal lamp 3 for each of the intersections A, B, C, and D when the segment is in a super-saturated state, and a non-saturation control A signal control parameter output unit 15 that transmits the signal control parameter determined by the unit 13 or the supersaturation control unit 14 to the controller 2 at each of the intersections A, B, C, and D.

  The sensor information processing unit 11 processes the output for each first vehicle sensor 4 and generates time-series information indicating the number of vehicles that have passed through the sensing area every n seconds (for example, 5 seconds). Further, based on this time series information, vehicle arrival prediction information at the intersection is generated for each inflow link of each intersection in the segment. In addition, the sensor information processing unit 11 processes the output of the first vehicle sensor 4 and calculates the traffic volume, occupation rate, average speed, and the like for the last five minutes on the inflow link at each intersection. Further, the vehicle detection signal of the second vehicle detector 5 is processed to estimate the number of remaining profits at the intersection B of the bottleneck.

  The supersaturation determination unit 12 determines whether or not there is a congested supersaturated state for each inflow link at the intersection B of the bottleneck. This determination is made based on the processing result of the sensor information processing unit 11.

  The desaturation control unit 13 is installed at each intersection A, B, C, D in the segment when the supersaturation determination unit 12 determines that all the inflow links at the intersection B of the bottleneck are in a non-saturated state. A signal control parameter for controlling the signal lamp 3 is determined. The supersaturation control unit 14 is installed at each of the intersections A, B, C, and D in the segment when the supersaturation determination unit 12 determines that any inflow link at the intersection B of the bottleneck is in a supersaturated state. A signal control parameter for controlling the signal lamp 3 is determined. The supersaturation control unit 14 evaluates each signal control parameter proposal based on the simulation result of the traffic situation simulation unit 21 that performs a simulation for predicting a change in traffic situation for each of the plurality of signal control parameter proposals, and the simulation result of the traffic situation simulation unit 21. In addition, a signal control parameter determination unit 22 that determines a signal control parameter plan to be actually used is provided. Although not shown, the desaturation control unit 13 is also provided with a configuration corresponding to the traffic condition simulation unit 21 and the signal control parameter determination unit 22. The signal control parameter output unit 15 transmits the signal control parameters for the signal lamps 3 at the intersections A, B, C, and D determined by the non-saturation control unit 13 or the supersaturation control unit 14 to each controller 2. Alternatively, each controller 2 is controlled by known step control according to the determined signal control parameter.

  The signal control apparatus 1 according to the embodiment of the present invention determines signal control parameters for the signal lamps 3 at the respective intersections A, B, C, and D in the segment by the following signal control parameter determination processing. FIG. 3 is a flowchart showing the signal control parameter determination process. This process is executed a certain time before the signal lamp 3 at the intersection B of the bottleneck starts the next cycle. In this process, the signal control parameter of the next cycle for the signal lamp 3 at each intersection A, B, C, D in the segment is determined. The signal control apparatus 1 determines whether or not it is in a supersaturated state for each inflow link at the intersection B of the bottleneck in the segment (s1). The supersaturation determination unit 12 performs the determination related to s1 based on the processing results of the outputs of the first vehicle sensor 4 and the second vehicle sensor 5 in the sensor information processing unit 11.

  The sensor information processing unit 11 processes the output of the second vehicle sensor 5 for each inflow link at the intersection B of the bottleneck, and estimates the remaining number of profits. The number of remaining cars is the number of vehicles that have stopped before intersection B due to a red light until a certain time T1 (for example, 10 seconds) has passed since switching to the red light, in other words, the blue time. This is the number of vehicles that could not be burned (vehicles that could not flow downstream through the intersection). When the inflow link is oversaturated, the remaining number of profits increases.

When the second vehicle detector 5 is an ultrasonic type or an optical type, the second vehicle detector 5 is installed such that a position corresponding to the number of remaining burners determined to be in a supersaturated state becomes a detection region. Specifically, if the remaining number of surpluses that are oversaturated is N or more and the distance between the heads when a normal vehicle is stopped is M (m), N × M (m) upstream from the stop line at intersection B It is installed so that the position of is the sensing area. For example, if the remaining number of vehicles that are determined to be in a supersaturated state is 7 and the distance between the heads of a normal vehicle when it is stopped is 7 m, the second vehicle is positioned so that the upstream position about 50 m from the stop line is the sensing area. A sensor 5 is installed. The vehicle traveling from the upstream toward the intersection B starts to decelerate if it is a red signal, and stops alongside the preceding vehicle at the time when the vehicle head is stopped. Therefore, as the number of stopped vehicles increases, FIG. As shown in FIG. 4, the deceleration position of the vehicle rises upstream of the inflow link. In FIG. 4, the horizontal axis indicates the horizontal position of the inflow link, and the vertical axis is the time axis. Moreover, each line shown in FIG. 4 is a locus of the vehicle. Here, the line connecting the points where the vehicle speed is reduced to a constant speed is generally called a stop wave. The passing speed of the vehicle in the sensing area of the second vehicle sensor 5 is
Passing speed of vehicle = average vehicle length / sensing time in sensing area (time when vehicle was in sensing area)
Can be calculated. By detecting this stop wave, the sensor information processing unit 11 estimates the number of remaining profits and notifies the oversaturation determination unit 12 of the estimated number.

  Further, when the second vehicle detector 5 is an image type, as shown in FIG. 5, the remaining number of vehicles that are determined to be supersaturated from the head vehicle (the vehicle stopped at the stop line) are determined. It is installed so that the stop position is included in the imaging area (sensing area). The sensor information processing unit 11 processes an image picked up by the second vehicle sensor 5 after a certain time T1 after switching to a red signal, and detects a vehicle that has stopped (that is, a vehicle that remains unsuccessful). The number is detected and notified to the supersaturation determination unit 12. When the second vehicle sensor 5 is an image type, the remaining number of burns can be detected directly, so that the detection accuracy of the remaining number of shots can be improved rather than using an optical or ultrasonic type. it can.

  In s1, it may be determined whether the bottleneck intersection B is in a supersaturated state or a non-saturated state only by the number of remaining profits. In this case, depending on the offset deviation from the adjacent upstream intersection, Even when the inflow link at the bottleneck intersection B is not supersaturated, most vehicles that have flowed out of the upstream intersection at the green light may stop at the red light at the bottleneck intersection B. In this case, although the inflow link at the intersection B of the bottleneck is not oversaturated, there is a possibility that the remaining number of profits exceeds the predetermined number that is determined to be oversaturated and erroneously determined to be oversaturated. Therefore, the signal control apparatus according to this embodiment uses the blue time utilization factor for determining whether or not the state is a supersaturated state related to s1.

FIG. 6 is a flowchart showing a process related to the supersaturation determination using the blue hour utilization rate. As described above, the signal control device 1 estimates the remaining number of units for each inflow link at the intersection B of the bottleneck, and calculates the blue hour utilization rate in the previous blue hour (s11, s12). The green hour utilization rate is a ratio of the number of vehicles that have passed the intersection B during the blue hour and the maximum number of vehicles that can pass the intersection B during the blue hour. Specifically, when the saturation traffic flow rate is n units / second and the green time is N seconds, the green time utilization rate is
Blue hour utilization rate = (number of vehicles actually passing through intersection B) / (N x n)
Is calculated by The number of vehicles actually passing the intersection can be calculated by processing the detection signal of the second vehicle detection 5. The calculation of the blue hour utilization rate is performed in the sensor information processing unit 11.

  The oversaturation determination unit 12 supersaturates the inflow link at s15 if the remaining number of surpluses exceeds the predetermined number and the green hour utilization rate is greater than a predetermined value, for example, 0.9 (s13, s14). In other cases, it is determined that the state is not saturated in s16.

  As described above, the supersaturation determination unit 12 determines whether or not the supersaturation state is present for each inflow link at the intersection B of the bottleneck. When it is determined that any of the inflow links is in a supersaturated state, it is determined in s1 that it is in a supersaturated state.

  When the signal control device 1 determines that the state is not the supersaturated state in s1, the non-saturation control unit 13 determines a signal control parameter for the intersection B of the bottleneck (s8). In s8, the arrival prediction information of the vehicle at the intersection B is generated for each inflow link at the intersection B of the bottleneck based on the detection signal from the first vehicle detector 4. Further, a plurality of types of signal control parameter proposals for the signal lamp 3 at the intersection B are generated. Then, for each of the proposed signal control parameters, the traffic condition is simulated using the arrival prediction information, and evaluation indexes such as a green time utilization rate, the number of stops, and a delay time are calculated. Then, a signal control parameter plan whose evaluation index is optimum, for example, a signal control parameter plan in which the blue time utilization rate of each inflow link is 0.9 or less and the number of times of stoppage and delay time is minimum is changed to the intersection B of the bottleneck. Is determined as a signal control parameter for controlling the signal lamp 3 installed in the. The desaturation control unit 13 also determines signal control parameters for the other intersections A, C, and D in the segment based on the vehicle arrival prediction information (s9).

  In the processing relating to s8 and s9, the order of the intersections A, B, C, and D for determining the signal control parameter may be any order.

  The signal control device 1 transmits the signal control parameters for the signal lamps 3 at the intersections A, B, C, and D in the segment determined by the desaturation control unit 13 from the signal control parameter output unit 15 to the corresponding controller 2. (S6). Each controller 2 controls the signal lamp 3 based on the signal control parameter transmitted from the signal control device 1.

  Next, the operation when it is determined in s1 that the state is supersaturated will be described. In the signal control device 1, the supersaturation control unit 14 determines signal control parameters for the signal lamp 3 at the intersection B of the bottleneck. The signal control parameter determination unit 22 generates a plurality of types of signal control parameter proposals, and the traffic condition simulation unit 21 determines the traffic conditions for each of these signal control parameter proposals up to a predetermined time, for example, about 15 minutes to 1 hour ahead. A simulation is performed (s2). In s2, for the current signal control parameter for the signal lamp 3 at the intersection B of the bottleneck, the split on the main road side is changed by -3 seconds, -2 seconds, and -1 second without changing the cycle and the offset. First, seven signal control parameter proposals of +1 second, +2 seconds, and +3 seconds are created.

  When the inside of the segment is supersaturated, the cycle of the signal lamp 3 at the intersection B of the bottleneck is determined according to the traffic situation in the segment at regular time intervals (for example, every 5 minutes). The cycle determined here is a common cycle for the other general intersections A, C and D in the segment. Further, based on the common cycle determined here, an offset is determined for each of the intersections A, B, C, and D. Details of this processing will be described later.

The traffic situation simulation unit 21 simulates the traffic situation for a predetermined time ahead for each proposed signal control parameter specified by the signal control parameter determination unit 22. This simulation will be described. The traffic situation simulation unit 21 estimates the number of traffic jams and the inflow traffic for each inflow link at the intersection B of the bottleneck. At this time, the traffic condition simulation unit 21 considers the number of upstream traffic jams and the branching rate, and calculates the traffic jam number of the inflow link at the intersection B of the bottleneck.
Number of traffic jams = Number of traffic jams on inflow links + Σ (number of traffic jams upstream) x (branch rate to inflow links)
Calculated by

Further, the inflow traffic is calculated for each inflow link at the intersection B of the bottleneck in consideration of the branching rate. At this time, the inflow rate is the product of the branching rate of each inflow link up to the inflow link (inflow link at the intersection B of the bottleneck)
Inflow traffic = Σ (traffic volume of upstream inflow link) x (product of branch rate to the inflow link)
Calculated by The traffic volume of the upstream inflow link is the number of vehicles for 5 minutes detected by the second vehicle detector 5 installed upstream of the inflow link. For example, if the traffic situation in the segment is the situation shown in FIG. 7, the number of traffic jams on the inflow link connecting intersections B and C is
Number of traffic jams = 50 + 30 x 95% + 20 x 30% = 84.5 (units)
And calculate. The inflow traffic of the inflow link connecting intersections B and C is
Inflow traffic = (100 x 95% + 20 x 30% + 20 x 30%) x 95%
+ (20 × 30%) + (20 × 30%) = 113.65 (unit)
And calculate.

  The traffic situation simulation unit 21 calculates the number of traffic jams created in the above process and the sum of the inflow traffic as traffic demand of the inflow link (traffic demand = number of traffic jams + inflow traffic). In addition, the traffic situation simulation unit 21 simulates the change in the number of traffic jams for each inflow link at the intersection B of the bottleneck for each signal control parameter plan in order to perform optimization by prediction. The prediction of the number of traffic jams will be made 15 minutes to 1 hour ahead. In this simulation, the number of traffic jams on the inflow link at the intersection B of the bottleneck is predicted every certain time (here, referred to as TimeStep), for example, every 5 minutes.

In this simulation, the number of traffic jams at time Tn + 1 (Queue (Tn + 1)) is calculated using the traffic volume predicted to flow in and the traffic volume flowing out.
Queue (Tn + 1) = Queue (Tn) + Σ (Qk (Tn + 1) × Tk) −S × G
And However, when Queue (Tn + 1) <0, Queue (Tn + 1) = 0. Also,
Queue (Tn): Number of traffic jams at time Tn Qk (Tn + 1): Predicted traffic volume flowing from time Tn to Tn + 1 at the most upstream link k Tk: Inflow rate from the most upstream link to the inflow link at the bottleneck intersection S: Inflow Saturated traffic flow rate G of link: Blue time of the inflow link between times Tn and Tn + 1.

  In the above simulation, the predicted traffic volume Qk (Tn + 1) may be a value obtained by statistically processing the traffic volume collected by the first vehicle detector 4 in the past, or a value calculated by a known past average pattern method. It may be used. This past average pattern method is a method of predicting a traffic flow transition pattern in the near future by comparing a past traffic flow transition pattern (traffic flow time transition pattern) with a current traffic flow transition pattern. The current traffic flow transition pattern is obtained from the detection signal of the first vehicle detector 4.

  The supersaturation control unit 21 obtains the change in the number of traffic jams shown in FIGS. 8A and 8B for each signal control parameter plan by this simulation. In FIG. 8, the vertical axis is the number of traffic jams, and the horizontal axis is the time axis. In addition, FIG. 8 shows the change in the number of traffic jams on the inflow links on the main road side and the secondary road side. FIG. 8A shows an example in which the traffic jams are not resolved, and FIG. 8B shows the traffic jams. It is an example in the case of eliminating.

The signal control parameter determination unit 22 determines, for each signal control parameter plan simulated by the traffic situation simulation unit 21, from the simulation result, as shown in FIG.
(B) The evaluation index shown is calculated. The evaluation index is a time difference (congestion elimination time difference) at which the supersaturated state (congestion) is resolved between the main road and the subordinate road, a total delay time, a main trunk maximum travel time, a subordinate maximum travel time, and a maximum travel time difference. FIG. 9A is an example in the case where the traffic jam is not eliminated, and FIG. 9B is an example in which the traffic jam is eliminated.

The difference in the time for canceling the traffic jam is the time when the traffic jam is resolved between the main road and the secondary road, that is, Queue.
(Tn) = 0 is the difference between the time and 0, and when the traffic jam is not resolved, “not resolved” is set. The total delay time is: Total delay time = Σ (Queue (Tn) × TimeStep)
Calculated by The maximum travel time of the main line and the maximum travel time of the secondary road are Max (Queue) × TimeStep / (S × G) in the simulation result of the inflow link, respectively.
Calculated by Max (Queue) is the maximum value of the number of traffic jams obtained by the above simulation. The maximum travel time difference is a difference between the maximum travel time of the main line and the maximum travel time of the secondary road calculated here.

  The signal control parameter determination unit 22 determines whether there is a simulation result with a plurality of signal control parameter proposals in which congestion is eliminated (oversaturated state is eliminated) (s3). If there is a signal control parameter proposal that eliminates the traffic jam, the signal control parameter determination unit 22 uses the signal control parameter draft that has the smallest difference in the traffic jam resolution time as the signal control parameter for the signal lamp 3 at the intersection B of the bottleneck. Determine (s4). For example, when the simulation result shown in FIG. 9B is obtained, the signal control parameter proposal No. 6 is determined as the signal control parameter for the signal lamp 3 at the intersection B of the bottleneck.

  Here, the No. 7 signal control parameter proposal is also the same as the No. 6 signal control parameter proposal with a traffic jam resolution time difference of 0, but the No. 6 signal control parameter proposal with a smaller total delay time is the bottleneck. The signal control parameter for the signal lamp 3 at the intersection B is determined. That is, if there is a signal control parameter proposal having the same traffic jam elimination time difference, the signal control parameter proposal having the smallest total delay time is determined as the signal control parameter for the signal lamp 3 at the intersection B of the bottleneck.

  In addition, when the signal control parameter determination unit 22 determines the signal control parameter for the signal lamp 3 at the intersection B of the bottleneck in s4, the signal control parameter determination unit 22 determines the signal control parameter for the general intersections A, C, and D in the segment. At this time, the signal control parameter determination unit 22 determines signal control parameters for controlling the signal lamps 3 at the general intersections A, C, and D by pattern selection control (s5).

The signal control device 1 stores a cycle length common to the intersections A, B, C, and D in the segment in association with the demand value indicating the traffic situation in the segment. The demand value is one of the indicators for traffic demand, and it takes the traffic volume normalized by a predetermined reference value and the larger normalized occupancy rate,
Demand value = Max (fixed time traffic volume / reference traffic volume, fixed time occupancy rate / reference occupancy rate)
Is calculated by The reference traffic volume and the reference occupancy rate are determined according to the traffic situation for each point.

The signal control device 1 calculates a demand value indicating the traffic situation in the segment at regular intervals, and sets the cycle length associated with the calculated demand value to each intersection A, B, C, D in the segment. Decide on a common cycle. Further, the signal control device 1 stores an offset in association with the common cycle length for the bottleneck intersection B, and corresponds to the common cycle length for the general intersections A, C, and D other than the bottleneck intersection B. In addition, the offset and split are stored. The signal control apparatus 1 determines the offset stored in association with the previously determined common cycle length for the bottleneck intersection B, and is common for the general intersections A, C, and D other than the bottleneck intersection B. The offset and split stored in association with the cycle length are determined.

  Thus, the signal control apparatus 1 determines the common cycle and offset of the bottleneck intersection B by so-called pattern selection control (as described in s2 above, the common cycle and offset of the bottleneck intersection B). Is determined at regular intervals.) For general intersections A, C, and D, the cycle, offset, and split of signal control parameters are all determined by pattern selection control.

  The signal control device 1 sends the signal control parameters for the signal lamps 3 at the intersections A, B, C, and D in the segment determined by the signal control parameter determination unit 22 from the signal control parameter output unit 15 to the corresponding controller 2. Transmit (s6). Each controller 2 controls the signal lamp 3 based on the signal control parameter transmitted from the signal control device 1.

  Further, if there is no signal control parameter proposal that eliminates the traffic jam, the signal control parameter determination unit 22 determines the signal control parameter for the signal lamp 3 at the intersection B of the bottleneck based on the control target specified at that time. (S7). For example, when the simulation result shown in FIG. 9A is obtained, if the designated control target is the minimization of the total delay time, the signal control parameter proposal No. 6 is changed to the signal lamp 3 at the intersection B of the bottleneck. The signal control parameter for is determined. If the designated control target is equality control, the No. 1 signal control parameter proposal with the smallest maximum travel time difference is determined as the signal control parameter for the signal lamp 3 at the intersection B of the bottleneck. Further, if the designated control target is priority control, the No. 7 signal control parameter proposal that minimizes the maximum travel time on the main road is determined as the signal control parameter for the signal lamp 3 at the intersection B of the bottleneck.

  The control target used when determining the signal control parameter in s7 can be arbitrarily set by a traffic controller or the like who is an administrator.

  Even when the signal control parameter determination unit 22 determines a signal control parameter for the signal lamp 3 at the intersection B at the bottleneck in s7, the signal control parameter determination unit 22 performs the above-described processing of s5 and performs the signal lamps of the general intersections A, C, and D in the segment. The signal control parameter for the device 3 is determined, and the signal control parameter is transmitted to each controller 2 in s6.

  As described above, when the inflow link at the intersection B of the bottleneck is in a supersaturated state (when traffic is congested), the signal control device 1 of this embodiment is When the oversaturated state is eliminated, the signal lamp 3 at the intersection B of the bottleneck is controlled with the signal control parameter that eliminates the oversaturated state earlier, so that the signal lamp 3 that can eliminate the oversaturated state early can be controlled. . In addition, since the signal control parameter with the shortest time difference at which the supersaturated state between the main road and the secondary road is resolved is determined, when either the main road or the secondary road is oversaturated and the other is oversaturated. The wasteful green time on the road side where the oversaturated state is eliminated can be suppressed. Usually, the utilization rate of the blue hours on the main road or the secondary road where the traffic congestion has been resolved first decreases.

  In addition, in the simulation result of the traffic situation conducted for a certain time ahead, when this oversaturated state is not resolved, the signal control parameter is determined based on the control target specified at that time. It is possible to control the signal lamp 3 according to the traffic situation and the manager's request.

  Further, when the supersaturated state is not eliminated, the maximum travel time of the secondary road may be additionally set as an evaluation index. For example, it is set to 300 seconds. It is assumed that the maximum travel time of a secondary road is 250 seconds at a certain blue hour when the traffic jam length is 300 m. In this case, in the proposed signal control parameter in which a simulation result in which the control target is the main line priority and the travel time of the main line is minimum is obtained, this simulation result is obtained when the maximum travel time on the secondary road exceeds 300 seconds. The proposed signal control parameter is not used as the proposed signal control parameter at the intersection B of the bottleneck.

  Further, the waiting time difference allowable range between the main line and the secondary road may be additionally set as an evaluation index. For example, the waiting time difference allowable range between the main line and the secondary road is set to 150 seconds. At a certain time, the waiting time of the main line is 100 seconds, and the waiting time of the secondary road is 200 seconds. In this case, in the signal control parameter plan in which the simulation result is obtained in which the control target is the main line priority and the travel time of the main line is the minimum, when the waiting time of the secondary road exceeds 250 seconds, the signal from which the simulation result is obtained The proposed control parameter is not the proposed signal control parameter at the intersection B of the bottleneck.

  In this way, it is possible to control the signal lamp 3 so that the influence on the secondary road side and the service difference between the main line and the secondary road do not become extremely large.

  In addition, since whether the inflow link of the bottleneck intersection B is oversaturated is determined based on the number of remaining profits and the green time utilization rate, it is possible to detect the occurrence of the oversaturated state at the bottleneck intersection B at an early stage. It is possible to suppress the control delay due to the traffic jam.

  In addition, since the proposed signal control parameter is generated based on the current signal control parameter, the signal control parameter greatly different from the current signal control parameter is not generated, and the influence of noise-like traffic demand fluctuation can be suppressed. The signal lamp 3 can be controlled stably.

  In addition, in the simulation results of the traffic situation conducted for a certain period of time, the administrator can arbitrarily set the control target used when determining the signal control parameter when this oversaturated state is not resolved. The control target can be easily changed according to changes in the general viewpoint and traffic conditions.

  In addition, since the signal control parameters of general intersections A, C, and D are determined by pattern selection control, the vehicle detector can be controlled without being installed on the secondary road, and substantially by the signal control parameters of intersection B of the bottleneck. Control within the segment is possible.

  In addition, when the inflow link at the intersection B of the bottleneck is not oversaturated and is not saturated, it is possible to control an appropriate signal lamp that allows the vehicle to smoothly flow downstream from the intersection B. However, it is possible to control the signal lamp device 3 appropriately.

In the above embodiment, it is determined whether or not the inflow link at the intersection B of the bottleneck at s2 is in a supersaturated state using the remaining number of profits and the green hour utilization rate. You may determine using. Specifically, a demand value is calculated for each predetermined point in the segment, and when the calculated demand value exceeds the set value, it is determined that the state is supersaturated. The demand value is one of the indexes representing traffic demand as described above, and is the traffic volume normalized by a predetermined reference value and the normalized occupancy rate which is larger.
Demand value = Max (fixed time traffic volume / reference traffic volume, fixed time occupancy rate / reference occupancy rate)
Is calculated by The reference traffic volume and the reference occupancy rate are determined according to the traffic situation for each point.

  In this case, the signal control device 1 acquires the traffic volume, the occupation rate, and the traveling speed of the vehicle for each inflow link based on the vehicle detection signal from the vehicle detector 4 every predetermined time, for example, every 5 minutes. . Then, a demand value is calculated for each inflow link, and it is determined whether or not the entire segment is in a supersaturated state. Thereby, although the oversaturation detection is slightly delayed, the oversaturation determination can be performed without installing the vehicle detector 5.

  In addition, whether or not the inflow link of the bottleneck intersection B in s2 is in a supersaturated state is comprehensively determined using both the above-mentioned number of remaining earnings, the green hour utilization rate, and this demand value. Also good. Specifically, as shown in FIG. 10, s20 is added, and when it is determined that there is a supersaturated state in the determination of either the number of remaining profits or the demand value, it is determined that the state is supersaturated. You can do it. Thereby, although it is a supersaturated state, it can suppress misjudging that it is a non-saturated state.

It is a figure which shows the structure of the signal control system which is embodiment of this invention. It is a block diagram which shows the function structure of the signal control apparatus which is embodiment of this invention. It is a flowchart which shows the signal control parameter determination process in the signal control apparatus which is embodiment of this invention. It is a figure explaining propagation of a stop wave. It is a figure explaining the vehicle detection area | region in an image type vehicle sensor. It is a flowchart which shows the supersaturation determination process in the signal control apparatus which is embodiment of this invention. It is a figure which shows the traffic condition in a segment. It is a figure which shows transition of the traffic congestion number obtained by the simulation by the signal control apparatus which is embodiment of this invention. It is a figure which shows the evaluation parameter | index obtained from the simulation result by the signal control apparatus which is embodiment of this invention. It is a flowchart which shows the supersaturation determination process in the signal control apparatus which is another embodiment of this invention.

Explanation of symbols

1-signal control device 2-controller 3-signal lamp 4-first vehicle sensor 5-second vehicle sensor 11-sensor information processing unit 12-supersaturation determination unit 13-unsaturation control unit 14-supersaturation control 15-Signal control parameter output unit 21-Traffic condition simulation unit 22-Signal control parameter determination unit

Claims (11)

In a signal control device for determining a signal control parameter for controlling a signal lamp installed at an intersection in a segment,
Supersaturation determination means for determining whether an inflow link at a predetermined important intersection is supersaturated or nonsaturated;
When the oversaturation determination means determines that the state is oversaturated, the traffic situation on the inflow link at the important intersection is predicted for a predetermined time for each of a plurality of proposed signal control parameters, and the evaluation index for the prediction result is optimal. Supersaturated signal control parameter determining means for determining the proposed signal control parameter as a signal control parameter for controlling the signal lamp installed at the important intersection,
The above-described supersaturated signal control parameter determining means is a signal control parameter that minimizes the time difference of oversaturated state cancellation between the main road and the secondary road at an important intersection when a prediction result that the supersaturated state is resolved by a predetermined time is obtained. A signal control device that determines a plan as a signal control parameter for controlling a signal lamp installed at an important intersection. With respect to the inflow link at the important intersection, a remaining remaining number detecting means for detecting whether the remaining number exceeds the predetermined number set in advance,
The oversaturation determining means determines that the inflow link at the important intersection is in a supersaturated state when the remaining number of remaining detected by the remaining remaining number detecting means exceeds a predetermined number. The signal control apparatus as described. A blue hour utilization rate detecting means for detecting a utilization time of a blue hour is provided for the inflow link at the important intersection,
In the oversaturation determination means, the remaining number of remaining detected by the remaining remaining number detecting means exceeds a predetermined number, and the blue hour utilization rate detected by the blue hour utilization rate detecting means is predetermined. The signal control device according to claim 2, wherein when the predetermined value is exceeded, the inflow link at the important intersection is determined to be in a supersaturated state. Stop vehicle detection means for detecting stop of the vehicle at a predetermined position upstream of the stop line of the important intersection,
The oversaturation determination means is configured to stop the vehicle at a predetermined position upstream of the stop line within a predetermined time after a signal lamp installed at the important intersection is switched to a red signal. The signal control device according to claim 1, wherein when it is detected, the inflow link at the important intersection is determined to be in a supersaturated state. Demand value calculation means for calculating the demand value indicating the traffic situation in the segment,
2. The signal control device according to claim 1, wherein the supersaturation determination unit determines that the inflow link of the important intersection is in a supersaturated state when the demand value calculated by the demand value calculation unit exceeds a predetermined value. .   When it is determined that the oversaturation determination means is in a non-saturated state, vehicle arrival prediction information is generated at the important intersection, and a signal lamp installed at the important intersection is generated based on the arrival prediction information generated here. The signal control apparatus according to claim 1, further comprising non-saturation signal control parameter determination means for determining a signal control parameter to be controlled.   The supersaturated signal control parameter determining means determines a common cycle for each intersection including the important intersection based on the traffic situation in the segment, and determines an offset for each intersection based on the cycle determined here. The function and the cycle previously determined for the important intersection, the function of generating a plurality of signal control parameter proposals with different splits by offset, and the above important intersection for each of the plurality of signal control parameter proposals generated here The signal control device according to claim 1, wherein a traffic situation on the inflow link is predicted for a predetermined time and a split at the important intersection is determined.   8. The signal control apparatus according to claim 7, wherein the supersaturated signal control parameter determining means determines a split based on a common cycle determined based on a traffic situation in a segment for each general intersection other than an important intersection in the segment. .   The supersaturation signal control parameter determining means estimates the number of vehicles flowing in from an intersection upstream from an inflow link at an important intersection using a branching rate determined in advance for the intersection. The signal control device according to claim 1, wherein a change in the number of vehicles staying on the link is predicted.   The supersaturated signal control parameter determining means uses, as an evaluation index, the maximum travel time, the time difference of oversaturated state cancellation, or the total delay time on the main road and the secondary road at an important intersection based on the prediction result for each of a plurality of signal control parameter proposals. The signal control device according to claim 1, wherein the signal control parameter is calculated and a signal control parameter for controlling a signal lamp installed at an important intersection is determined based on the calculated evaluation index.   As a control target used when the above-mentioned supersaturated signal control parameter determining means determines a signal control parameter for controlling a signal lamp installed at an important intersection, equalization of the maximum travel time on the main road and the secondary road at the important intersection The signal control device according to claim 10, further comprising: a control target designating unit that designates either minimizing a maximum travel time on a main road or minimizing a total delay time.

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