Traffic signal lamp control method

Abstract

The invention discloses a traffic signal lamp control method. The method comprises the steps of firstly predicting a first traffic flow and a first congestion level of a target area at a first moment; if the first congestion level is a serious congestion level, determining a second signal lamp timing scheme of the intersection according to the current first signal lamp timing scheme and the signal lamp timing adjustment amount of the intersection for each intersection at the upstream of the target area; if the first congestion level is a general congestion level or a slow traffic congestion level, determining a second traffic flow difference value between the first traffic flow and a traffic flow lower boundary value of a traffic flow range to which the first traffic flow belongs; obtaining a third traffic flow difference value between the traffic flow upper boundary value and the traffic flow lower boundary value of the traffic flow range; and for each intersection, determining a fifth signal lamp timing scheme of the intersection according to a first ratio of the second traffic flow difference value to the third traffic flow difference value. According to the invention, the signal timing scheme of the intersection can be automatically adjusted according to the change of the congestion condition of the target area, and the accuracy of traffic signal lamp control is improved.

Description

Technical Field

[0001] This application relates to the technical field of intelligent traffic control, and particularly to a traffic signal control method. Background Art

[0002] With the increasing traffic demand, traffic congestion has gradually shifted from intersection congestion and road section congestion to road network area congestion. How to reasonably regulate the traffic flow into and out of the road network to achieve the balance between traffic supply and demand in the road network is the key to solving the congestion in the road network area. In the field of traffic signal control, the congestion control that has been achieved in the industry is mainly the adaptive control for congested intersections and congested main lines. The control for congested areas still relies on manual temporary intervention, which is time-consuming and laborious, and the effect is unstable, and the accuracy of signal control is poor. Summary of the Invention

[0003] This application provides a traffic signal control method to solve the problem of poor accuracy of signal control in the prior art.

[0004] In a first aspect, this application provides a traffic signal control method, and the method includes:

[0005] Predict the first traffic flow of the target area at the first moment according to the first historical traffic flow of the target area; determine the first congestion level corresponding to the first traffic flow range to which the first traffic flow belongs according to the traffic flow ranges respectively corresponding to different congestion levels pre-stored;

[0006] If the first congestion level is the severe congestion level, obtain the lower boundary value of the traffic flow of the first traffic flow range, determine the first traffic flow difference between the first traffic flow and the lower boundary value of the traffic flow; determine the signal timing adjustment amount according to the first traffic flow difference; for each intersection upstream of the target area, determine the second signal timing plan of the intersection according to the current first signal timing plan of the intersection and the signal timing adjustment amount, and control the signal lights of the intersection according to the second signal timing plan;

[0007] If the first congestion level is the general congestion level or the slow-moving congestion level, obtain the upper boundary value and the lower boundary value of the traffic flow in the first traffic flow range, and determine the second traffic flow difference between the first traffic flow and the lower boundary value of the traffic flow; and the third traffic flow difference between the upper boundary value and the lower boundary value of the traffic flow; for each intersection upstream of the target area, determine the difference between the green signal ratio of the signal lights in the third signal light timing plan corresponding to the intersection under the first congestion level and the green signal ratio of the signal lights in the fourth signal light timing plan corresponding to the intersection under the previous congestion level of the first congestion level; according to the first ratio of the second traffic flow difference to the third traffic flow difference, and the difference, determine the fifth signal light timing plan for the intersection, and control the signal lights of the intersection according to the fifth signal light timing plan;

[0008] Among them, the previous congestion level of the slow-moving congestion level is the general congestion level, and the previous congestion level of the general congestion level is the severe congestion level; the traffic flow values included in the traffic flow range corresponding to the slow-moving congestion level are less than the traffic flow values included in the traffic flow range corresponding to the general congestion level, and the traffic flow values included in the traffic flow range corresponding to the general congestion level are less than the traffic flow values included in the traffic flow range corresponding to the severe congestion level.

[0009] The above technical solution has the following advantages or beneficial effects:

[0010] In this application, first predict the first traffic flow of the target area at the first moment, and determine the first congestion level of the target area at the first moment according to the first traffic flow; if the first congestion level is the severe congestion level, determine the signal light timing adjustment amount according to the first traffic flow difference between the first traffic flow and the lower boundary value of the traffic flow; for each intersection upstream of the target area, according to the current first signal light timing plan and the signal light timing adjustment amount of the intersection, determine the second signal light timing plan for the intersection, and control the signal lights of the intersection according to the second signal light timing plan. For the severe congestion situation in the target area, the degree of adjustment of the signal light timing plan is relatively large. Based on the above considerations, this application combines the predicted first traffic flow of the target area and the lower boundary value of the traffic flow in the first traffic flow range corresponding to the severe congestion level to determine the signal light timing adjustment amount, so that a relatively large signal light timing adjustment amount can be obtained. Then adjust the current first signal light timing plan according to the signal light timing adjustment amount to obtain the adjusted second signal light timing plan. The second signal light timing plan determined in this way can more effectively relieve the congestion pressure in the target area;

[0011] If the first congestion level is the general congestion level or the slow congestion level, determine the second traffic flow difference between the first traffic flow and the lower boundary value of the traffic flow range to which it belongs; and the third traffic flow difference between the upper boundary value and the lower boundary value of the traffic flow range to which it belongs; for each intersection, determine the fifth signal timing plan for the intersection according to the first ratio of the second traffic flow difference to the third traffic flow difference, and control the signal lights at the intersection according to the fifth signal timing plan. For the situation of general congestion or slow congestion in the target area, if the signal timing plan is adjusted too much, it may cause the accuracy of the signal timing adjustment to decrease. Therefore, the present application proposes a method for determining the adjusted fifth signal timing plan based on the upper boundary value and the lower boundary value of the traffic flow range of the first traffic flow range, as well as the green signal ratio corresponding to the current congestion level and the green signal ratio of the previous congestion level determined in advance. Based on the fifth signal timing plan, the congestion degree of the target area can be effectively alleviated.

[0012] In the present application, the signal timing plan of the intersection can be automatically adjusted according to the change of the congestion situation in the target area, improving the accuracy of traffic signal control. And based on the above considerations, for different congestion situations in the target area, different methods or different parameters are used to determine the adjusted signal timing plan, so as to further improve the accuracy of traffic signal control.

[0013] In a second aspect, the present application provides a traffic signal control device, the device includes:

[0014] A first determination module, configured to predict the first traffic flow of the target area at the first moment according to the first historical traffic flow of the target area; and determine the first congestion level corresponding to the first traffic flow range to which the first traffic flow belongs according to the traffic flow ranges corresponding to different congestion levels stored in advance;

[0015] A first control module, configured to, if the first congestion level is the severe congestion level, obtain the lower boundary value of the traffic flow range of the first traffic flow, determine the first traffic flow difference between the first traffic flow and the lower boundary value of the traffic flow range; determine the signal timing adjustment amount according to the first traffic flow difference; for each intersection upstream of the target area, determine the second signal timing plan for the intersection according to the current first signal timing plan of the intersection and the signal timing adjustment amount, and control the signal lights at the intersection according to the second signal timing plan;

[0016] The second control module is configured to, if the first congestion level is a general congestion level or a slow-moving congestion level, obtain the upper traffic flow boundary value and the lower traffic flow boundary value of the first traffic flow range, and determine the second traffic flow difference between the first traffic flow and the lower traffic flow boundary value; and the third traffic flow difference between the upper traffic flow boundary value and the lower traffic flow boundary value; for each intersection upstream of the target area, determine the difference between the green signal ratio of the signal lights in the third signal light timing plan corresponding to the intersection under the first congestion level and the green signal ratio of the signal lights in the fourth signal light timing plan corresponding to the intersection under the previous congestion level of the first congestion level; according to the first ratio of the second traffic flow difference to the third traffic flow difference, and the difference, determine the fifth signal light timing plan for the intersection, and control the signal lights of the intersection according to the fifth signal light timing plan;

[0017] Wherein, the previous congestion level of the slow-moving congestion level is the general congestion level, and the previous congestion level of the general congestion level is the severe congestion level; the traffic flow values included in the traffic flow range corresponding to the slow-moving congestion level are less than the traffic flow values included in the traffic flow range corresponding to the general congestion level, and the traffic flow values included in the traffic flow range corresponding to the general congestion level are less than the traffic flow values included in the traffic flow range corresponding to the severe congestion level.

[0018] In a third aspect, the present application provides an electronic device, including a processor, a communication interface, a memory, and a communication bus. Among them, the processor, the communication interface, and the memory complete communication with each other through the communication bus;

[0019] The memory is used for storing a computer program;

[0020] The processor is configured to implement the described method when executing the program stored on the memory.

[0021] In a fourth aspect, the present application provides a computer-readable storage medium, where a computer program is stored in the computer-readable storage medium, and the computer program implements the described method when executed by a processor.

[0022] In a fifth aspect, the present application provides a computer program product, where the computer program product includes an executable program, and the executable program implements the described method when executed by a processor. Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 Schematic diagram of the traffic signal control process provided for this application;

[0025] Figure 2 Another schematic diagram of the traffic signal control process provided for this application;

[0026] Figure 3 Schematic diagram of the process for pre-determining the signal timing plan corresponding to each congestion level at the intersection provided for this application;

[0027] Figure 4 Schematic diagram of the traffic signal control framework provided for this application;

[0028] Figure 5 Schematic diagram of the process for generating the strategy plan provided for this application;

[0029] Figure 6 Schematic diagram of the traceability provided for this application;

[0030] Figure 7 Flowchart of the execution and update of the strategy plan provided for this application;

[0031] Figure 8 Schematic diagram of the pre-event - strategy plan recommendation interface provided for this application;

[0032] Figure 9 Schematic diagram of the in-event - real-time traceability and prediction interface provided for this application;

[0033] Figure 10 Schematic diagram of the in-event - congestion warning and plan recommendation interface provided for this application;

[0034] Figure 11 Schematic diagram of the in-event - plan adaptive adjustment interface provided for this application;

[0035] Figure 12 Schematic diagram of the structure of the traffic signal control device provided for this application;

[0036] Figure 13 Schematic diagram of the structure of the electronic device provided for this application. Detailed implementation manners

[0037] To make the objectives and implementation manners of this application clearer, the following will clearly and completely describe the exemplary implementation manners of this application with reference to the accompanying drawings in the exemplary embodiments of this application. Obviously, the described exemplary embodiments are only a part of the embodiments of this application, rather than all of the embodiments.

[0038] Note that the brief description of terms in this application is only for facilitating the understanding of the following described embodiments, rather than intending to limit the embodiments of this application. Unless otherwise specified, these terms should be understood in their ordinary and common meanings.

[0039] In this application, terms such as "first", "second", "third", etc. in the description, claims and the above-mentioned drawings are used to distinguish similar or like objects or entities, and do not necessarily mean to limit a specific order or sequence, unless otherwise noted. It should be understood that such terms used can be interchanged under appropriate circumstances.

[0040] The terms "comprising" and "having" and any variations thereof are intended to cover but not exclude inclusion. For example, a product or device comprising a series of components does not necessarily have to be limited to all the components clearly listed, but may include other components not clearly listed or inherent to these products or devices.

[0041] The term "module" refers to any known or later developed hardware, software, firmware, artificial intelligence, fuzzy logic, or a combination of hardware and / or software code that can perform functions related to that element.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, rather than to limit them; although this application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of this application.

[0043] For the convenience of explanation, the above description has been made in combination with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. According to the above teachings, various modifications and variations can be obtained. The selection and description of the above embodiments are for better explaining the principles and practical applications, so that those skilled in the art can better use the embodiments and various different modified embodiments suitable for specific use considerations.

[0044] With the increasing traffic demand, traffic congestion has gradually shifted from intersection congestion and section congestion to road network area congestion. How to reasonably regulate the traffic flow into and out of the road network to achieve the balance between traffic supply and demand in the road network is the key to solving road network area congestion. In the field of traffic signal control, the congestion control that has been achieved in the industry is mainly the adaptive control for congested intersections and congested main lines. The control for congested areas still relies on manual temporary intervention, which is time-consuming and laborious, and the effect is unstable.

[0045] To alleviate the congestion caused by gatherings in areas such as scenic spots, commercial areas, and hospitals, it is necessary to first understand the formation and evacuation rules of regional congestion, and then generate corresponding signal control strategies according to the control objectives. In terms of exploring the formation and evacuation rules of regional congestion, relevant technologies have already disclosed implementation solutions for automatic identification of congested areas, vehicle flow tracing, and flow prediction. Therefore, this application will not elaborate on related technologies. This application focuses on how to generate signal control strategies for congested areas caused by gatherings, and will directly use the results of vehicle flow tracing and flow prediction.

[0046] This application can automatically generate signal timing plans for peripheral access channels in different congestion levels for congested areas caused by gatherings. After the plan is implemented, the intersections on the channels can automatically adjust the signal timing plans of the intersections according to the congestion changes upstream and downstream. This application has broken through the industry problems of intelligent control in congested areas caused by gatherings, achieved the goal of controlling the overall inflow volume of the control area and balancing the traffic flow of each path, and improved the overall traffic efficiency of the road network. After being applied in the test area, the congestion index of the area has decreased.

[0047] Figure 1 The following is a schematic diagram of the traffic signal control process provided by this application, including the following steps:

[0048] S101: Predict the first traffic flow of the target area at the first moment according to the first historical traffic flow of the target area; determine the first congestion level corresponding to the first traffic flow range to which the first traffic flow belongs according to the traffic flow range corresponding to each different congestion level pre-saved;

[0049] S102: If the first congestion level is the severe congestion level, obtain the lower boundary value of the traffic flow in the first traffic flow range, and determine the first traffic flow difference between the first traffic flow and the lower boundary value of the traffic flow; determine the signal timing adjustment amount according to the first traffic flow difference; for each intersection upstream of the target area, determine the second signal timing plan of the intersection according to the current first signal timing plan of the intersection and the signal timing adjustment amount, and control the signal lights of the intersection according to the second signal timing plan;

[0050] S103: If the first congestion level is the general congestion level or the slow-moving congestion level, obtain the upper boundary value and the lower boundary value of the traffic flow within the first traffic flow range, and determine the second traffic flow difference between the first traffic flow and the lower boundary value of the traffic flow; and the third traffic flow difference between the upper boundary value and the lower boundary value of the traffic flow; for each intersection upstream of the target area, determine the difference between the green signal ratio of the signal lights in the third signal light timing plan corresponding to the intersection under the first congestion level and the green signal ratio of the signal lights in the fourth signal light timing plan corresponding to the intersection under the previous congestion level of the first congestion level; according to the first ratio of the second traffic flow difference to the third traffic flow difference, and the difference, determine the fifth signal light timing plan for the intersection, and control the signal lights at the intersection according to the fifth signal light timing plan;

[0051] Among them, the previous congestion level of the slow-moving congestion level is the general congestion level, and the previous congestion level of the general congestion level is the severe congestion level; the traffic flow values included in the traffic flow range corresponding to the slow-moving congestion level are less than the traffic flow values included in the traffic flow range corresponding to the general congestion level, and the traffic flow values included in the traffic flow range corresponding to the general congestion level are less than the traffic flow values included in the traffic flow range corresponding to the severe congestion level.

[0052] The traffic signal control method provided by this application is applied to an electronic device, which can be a smart phone, a personal computer, a tablet computer, a server and other devices.

[0053] The target area can be pre-defined by the user. The electronic device predicts the first traffic flow of the target area at the first moment according to the first historical traffic flow of the target area in the historical time period before the first moment. For example, according to the first historical traffic flow of the target area from 8:15 to 8:30, predict the first traffic flow of the target area at 8:35. Optionally, the electronic device deploys a pre-trained traffic flow prediction model, inputs the first historical traffic flow of the target area into the traffic flow prediction model, and predicts the first traffic flow of the target area at the first moment. The training process of the traffic flow prediction model can be: input the traffic flow within the sample history 15 minutes before the sample moment in the training set of the target area and the labeled traffic flow at the moment 5 minutes after the sample moment into the traffic flow prediction model to be trained, and predict the predicted traffic flow at the moment 5 minutes after the sample moment based on the traffic flow prediction model, and calculate the model loss value according to the predicted traffic flow and the labeled traffic flow. Through iterative training, when the loss value meets the requirements, or the number of iterations reaches the threshold, it is determined that the traffic flow prediction model training is completed.

[0054] Predict the first traffic flow of the target area at the first moment; according to the traffic flow ranges corresponding to different congestion levels pre - saved, determine the first congestion level corresponding to the first traffic flow range to which the first traffic flow belongs. In the electronic device, the traffic flow ranges corresponding to each congestion level are pre - configured, and each congestion level includes a severe congestion level, a general congestion level, and a slow - moving congestion level. For example, the traffic flow range corresponding to the slow - moving congestion level is (Q1, Q2], the traffic flow range corresponding to the general congestion level is (Q2, Q3], and the traffic flow range corresponding to the severe congestion level is >Q3. For example, if the first traffic flow range to which the first traffic flow of the target area at the first moment belongs is (Q1, Q2], then determine the first congestion level as the slow - moving congestion level.

[0055] In addition, to make the determination of the first congestion level more accurate, the first congestion index of the target area can also be predicted, and according to the congestion index ranges corresponding to different congestion indexes pre - saved, determine the first congestion level corresponding to the first congestion index range to which the first congestion index belongs. For example, the congestion index range corresponding to the slow - moving congestion level is (1.4, 1.7], the traffic flow range corresponding to the general congestion level is (1.7, 1.9], and the traffic flow range corresponding to the severe congestion level is >1.9. For example, if the first congestion index range to which the first congestion index of the target area at the first moment belongs is (1.4, 1.7], then determine the first congestion level as the slow - moving congestion level.

[0056] Optionally, the electronic device deploys a pre - trained congestion index prediction model, inputs the congestion indexes of historical moments of the target area into the traffic flow prediction model, and predicts the first congestion index of the target area at the first moment. The training process of the congestion index prediction model can be as follows: input the congestion indexes of historical moments obtained every 5 minutes within 15 minutes before the sample moment in the training set of the target area and the label congestion index at the moment 5 minutes after the sample moment into the congestion index prediction model to be trained. Based on the congestion index prediction model, predict the predicted congestion index at the moment 5 minutes after the sample moment, and calculate the model loss value according to the predicted congestion index and the label congestion index. Through iterative training, when the loss value meets the requirements or the number of iterations reaches the threshold, it is determined that the congestion index prediction model is trained.

[0057] It should be noted that the above 15 minutes, 5 minutes, etc. are only for illustrative purposes, and this application does not limit the specific time length. In addition, this application can use related technologies to obtain the traffic flow and congestion index of the target area. For example, according to the monitoring data collected by the monitoring devices at each intersection, track the license plates to obtain the traffic flow, congestion index, etc. of the target area.

[0058] Then retain the higher first congestion level determined according to the first congestion index and the first congestion level determined according to the first traffic flow. It should be noted that the severe congestion level is higher than the general congestion level, and the general congestion level is higher than the slow congestion level.

[0059] For example, if the first congestion level determined according to the first congestion index is the severe congestion level and the first congestion level determined according to the first traffic flow is the general congestion level, then retain the severe congestion level. That is to say, the finally determined first congestion level is the severe congestion level. If the first congestion level determined according to the first congestion index is the same as the first congestion level determined according to the first traffic flow, then retain any one of the first congestion levels.

[0060] If the first congestion level is the severe congestion level, obtain the lower boundary value of the traffic flow in the first traffic flow range, and determine the first traffic flow difference between the first traffic flow and the lower boundary value of the traffic flow; determine the signal timing adjustment amount according to the first traffic flow difference. Among them, min(int(Q i -Q1) / 100, 3) is the signal timing adjustment amount; Q i is the first traffic flow, and Q1 is the lower boundary value of the traffic flow in the traffic flow range corresponding to the severe congestion level. For each intersection upstream of the target area, according to the current first signal timing plan of the intersection and the signal timing adjustment amount, determine the second signal timing plan of the intersection, and control the signal lights of the intersection according to the second signal timing plan.

[0061] Among them, the signal timing plan includes the green light duration, the signal cycle duration, and the signal green ratio. The signal green ratio is the ratio of the green light duration to the signal cycle duration. The process of determining the second signal timing plan of the intersection according to the current first signal timing plan of the intersection and the signal timing adjustment amount can be to keep the signal cycle duration of the first signal timing plan and the second signal timing plan unchanged, and subtract the adjusted green light duration in the signal timing adjustment amount from the green light duration in the first signal timing plan as the green light duration in the second signal timing plan. Preferably, before adjusting the signal timing plan, it can also be first determined whether the first traffic flow is greater than a preset traffic flow threshold. If so, then perform subsequent adjustments; otherwise, do not make adjustments.

[0062] Preferably, determining the second signal timing plan of the intersection according to the current first signal timing plan of the intersection and the signal timing adjustment amount includes:

[0063] If Q i > Q1+(Q1-Q2) / 100, determine that the green light duration in the second signal timing plan of the intersection is g i1= g0 - min(int(Q i - Q1) / 100, 3); where, min(int(Q i - Q1) / 100, 3) is the signal timing adjustment amount of the signal light; when g i1 < g min , calculate Δg = g min - g i1 ; let g i1 = g min , determine that the cycle length in the second signal timing plan of the intersection is C i = C + Δg; where, Q i is the first traffic flow, Q1 is the lower boundary value of the traffic flow in the traffic flow range corresponding to the severe congestion level, Q2 is the lower boundary value of the traffic flow in the traffic flow range corresponding to the general congestion level, g i1 is the green light duration in the second signal timing plan, g0 is the green light duration in the current first signal timing plan, g min is the minimum green light duration configured for the intersection, C is the cycle length in the current first signal timing plan, and C i is the cycle length in the second signal timing plan of the intersection.

[0064] It should be noted that if Q i ≤ Q1 + (Q1 - Q2) / 100, the adjustment of the signal timing plan can be not carried out.

[0065] If the first congestion level is the general congestion level, obtain the upper boundary value and the lower boundary value of the traffic flow in the first traffic flow range, and determine the second traffic flow difference between the first traffic flow and the lower boundary value of the traffic flow; and the third traffic flow difference between the upper boundary value and the lower boundary value of the traffic flow; for each intersection upstream of the target area, determine the difference between the green signal ratio of the signal light in the third signal timing plan corresponding to the intersection under the general congestion level and the green signal ratio of the signal light in the fourth signal timing plan corresponding to the intersection under the severe congestion level; according to the first ratio of the second traffic flow difference to the third traffic flow difference and the difference, determine the fifth signal timing plan of the intersection, and control the signal light of the intersection according to the fifth signal timing plan.

[0066] Preferably, determining the fifth signal timing plan of the intersection according to the first ratio of the second traffic flow difference to the third traffic flow difference and the difference includes:

[0067] If the first congestion level is the general congestion level, calculate the green signal ratio λ according to the formula i , when λ i ≤ g1 / C1, take λi = g1 / C1; When the signal light cycle duration remains unchanged, then: When calculating g i2 < g min , then take g i2 = g min ; In the formula, g2 is the green light duration in the third signal light timing plan corresponding to the pre-determined general congestion level, c2 is the cycle duration in the third signal light timing plan corresponding to the pre-determined general congestion level, g1 is the signal light cycle duration in the fourth signal light timing plan corresponding to the pre-determined severe congestion level, c1 is the cycle duration in the fourth signal light timing plan corresponding to the pre-determined severe congestion level, and g i2 is the green light duration in the fifth signal light timing plan.

[0068] If the first congestion level is the slow congestion level, obtain the upper boundary value and lower boundary value of the traffic flow in the first traffic flow range, and determine the second traffic flow difference between the first traffic flow and the lower boundary value of the traffic flow; and the third traffic flow difference between the upper boundary value and the lower boundary value of the traffic flow; for each intersection upstream of the target area, determine the difference in the green signal ratio between the third signal light timing plan corresponding to the intersection at the slow congestion level and the fourth signal light timing plan corresponding to the intersection at the general congestion level; according to the first ratio of the second traffic flow difference to the third traffic flow difference, and the difference, determine the fifth signal light timing plan for the intersection, and control the signal lights at the intersection according to the fifth signal light timing plan.

[0069] Preferably, if the first congestion level is the slow congestion level, according to the formula Calculate the green signal ratio λ i , when λ i ≤ g2 / C2, take λ i = g2 / C2; When the signal light cycle duration remains unchanged, then: When calculating g i2 < g min , then take g i2 = g min ; In the formula, g3 is the green light duration in the third signal light timing plan corresponding to the pre-determined slow congestion level, c3 is the cycle duration in the third signal light timing plan corresponding to the pre-determined slow congestion level, g2 is the green light duration in the fourth signal light timing plan corresponding to the pre-determined general congestion level, c2 is the cycle duration in the fourth signal light timing plan corresponding to the pre-determined general congestion level, and g i2 is the green light duration in the fifth signal light timing plan.

[0070] In this application, first, the first traffic flow of the target area at the first moment is predicted, and the first congestion level of the target area at the first moment is determined according to the first traffic flow. If the first congestion level is the severe congestion level, the signal timing adjustment amount is determined according to the first traffic flow difference between the first traffic flow and the lower boundary value of the traffic flow range. For each intersection upstream of the target area, according to the current first signal timing plan of the intersection and the signal timing adjustment amount, the second signal timing plan of the intersection is determined, and the signal lights at the intersection are controlled according to the second signal timing plan. For the case of severe congestion in the target area, the degree of adjustment of the signal timing plan is relatively large. Based on the above considerations, this application combines the predicted first traffic flow of the target area and the lower boundary value of the traffic flow range corresponding to the severe congestion level to determine the signal timing adjustment amount, so that a relatively large signal timing adjustment amount can be obtained. Then, the current first signal timing plan is adjusted according to the signal timing adjustment amount to obtain the adjusted second signal timing plan. The second signal timing plan determined in this way can more effectively relieve the congestion pressure in the target area;

[0071] If the first congestion level is the general congestion level or the slow congestion level, the second traffic flow difference between the first traffic flow and the lower boundary value of the traffic flow range to which it belongs is determined; and the third traffic flow difference between the upper boundary value and the lower boundary value of the traffic flow range to which it belongs is determined. For each intersection, according to the first ratio of the second traffic flow difference to the third traffic flow difference, the fifth signal timing plan of the intersection is determined, and the signal lights at the intersection are controlled according to the fifth signal timing plan. For the case of general congestion or slow congestion in the target area, if the signal timing plan is adjusted too much, it may cause the accuracy of the signal timing adjustment to decrease. Therefore, this application proposes a method for determining the adjusted fifth signal timing plan based on the upper boundary value and the lower boundary value of the traffic flow range of the first traffic flow, as well as the green signal ratio corresponding to the current congestion level and the green signal ratio of the previous congestion level determined in advance. Based on the fifth signal timing plan, the congestion degree in the target area can be effectively relieved.

[0072] In this application, the signal timing plan of the intersection can be automatically adjusted according to the change of the congestion situation in the target area, improving the accuracy of traffic signal control. And based on the above considerations, for different congestion situations in the target area, different methods or different parameters are used to determine the adjusted signal timing plan, so as to further improve the accuracy of traffic signal control.

[0073] Figure 2 Another schematic diagram of the traffic signal control process provided by this application includes the following steps:

[0074] S201: Predict the second traffic flow of the target area at the second moment according to the second historical traffic flow of the target area; determine the second congestion level corresponding to the second traffic flow range to which the second traffic flow belongs according to the traffic flow ranges corresponding to different congestion levels pre - saved.

[0075] S202: For each intersection upstream of the target area, determine the sixth signal timing plan corresponding to the intersection at the second congestion level according to the signal timing plans corresponding to the intersection at each congestion level determined in advance; control the traffic lights at the intersection according to the sixth signal timing plan.

[0076] In this application, before predicting the first traffic flow of the target area at the first moment according to the first historical traffic flow of the target area, predict the second traffic flow of the target area at the second moment according to the second historical traffic flow of the target area; determine the corresponding second congestion level according to the second traffic flow. It should be noted that if the first traffic flow range to which the first traffic flow belongs is the same as the second traffic flow range to which the second traffic flow belongs, the first congestion level and the second congestion level are the same. If the first traffic flow range to which the first traffic flow belongs is different from the second traffic flow range to which the second traffic flow belongs, the first congestion level and the second congestion level are different.

[0077] For each intersection upstream of the target area, there are signal timing plans corresponding to the intersection at each congestion level of the target area determined in advance, and then determine the sixth signal timing plan corresponding to the intersection at the second congestion level of the target area; control the traffic lights at the intersection according to the sixth signal timing plan. This application automatically generates signal timing plans for each intersection upstream under different congestion conditions according to the congestion situation of the target area. Then predict the first traffic flow of the target area at the first moment according to the first historical traffic flow of the target area, and determine the first congestion level corresponding to the first traffic flow. Automatically adjust the signal timing plan of the intersection according to the change of the congestion situation of the target area, which improves the accuracy of traffic light control.

[0078] It should be noted that the process of determining the second congestion level is the same as the above - mentioned process of determining the first level, and will not be elaborated here.

[0079] In this application, first, there are multiple signal timing plans pre - configured at each intersection, which has nothing to do with the congestion level, and are called candidate signal timing plans (such as candidate signal timing plan 1, candidate signal timing plan 2,... candidate signal timing plan 10, etc.).

[0080] Then, for different congestion levels, select the signal light timing plan corresponding to the congestion level from these 10 candidate signal light timing plans. For example, determine that the signal light timing plan 3 corresponds to the severe congestion level, the signal light timing plan 5 corresponds to the general congestion level, and the signal light timing plan 8 corresponds to the slow congestion level. After the plan is executed, determine the corresponding signal light timing plan according to the congestion level, and then control the signal lights according to the corresponding signal light timing plan. For example, if the predicted target area is at the severe congestion level, control the signal lights according to the signal light timing plan 3.

[0081] After controlling the signal lights according to the signal light timing plan corresponding to the congestion level, continue to monitor the congestion level of the target area and adjust the signal light timing plan; the specific adjustment process has been described and will not be elaborated here.

[0082] Figure 3 The process schematic diagram for pre-determining the signal light timing plan corresponding to each congestion level provided by this application includes the following steps:

[0083] S301: For each of the congestion levels, determine the signal light timing plan corresponding to the intersection at the congestion level through the following steps:

[0084] S302: Obtain the preset traffic flow adjustment value corresponding to the congestion level, and determine the median traffic flow of the traffic flow range corresponding to the congestion level; determine the outgoing traffic flow of the target area during the historical time period; determine the third traffic flow in the target area according to the median traffic flow and the traffic flow adjustment value; determine the second ratio of the number of internal driving vehicles monitored in the target area to the total number of monitored driving vehicles during the historical time period, and determine the traffic flow control amount according to the second ratio, the third traffic flow, and the outgoing traffic flow.

[0085] It should be noted that the number of internal driving vehicles refers to the number of vehicles that are only driving within the target area monitored by the cameras in the target area, and the total number of monitored driving vehicles refers to the sum of the number of vehicles that are only driving within the target area monitored by the cameras in the target area and the number of vehicles entering and leaving the target area. The number of vehicles involved in this application refers to the number of vehicles after de-duplication according to the license plate. For example, for a certain vehicle, it has traveled multiple times within a certain time period, and multiple driving trajectories of this vehicle have been captured, but this vehicle is only recorded as the number of vehicles 1.

[0086] S303: Determine the number of lanes on the upstream road section associated with the intersection that lead to the target area according to the lane directions of each lane on the upstream road section; for each candidate signal timing plan pre-configured for the intersection, determine the number of passing vehicles within a preset duration according to the number of lanes and the green signal ratio in the candidate signal timing plan; determine the traffic capacity parameter corresponding to the candidate signal timing plan according to the third ratio of the number of passing vehicles to the saturated headway corresponding to the upstream road section.

[0087] S304: Determine the allowable number of queuing vehicles on the upstream road section according to the number of lanes on the upstream road section associated with the intersection that lead to the target area and the length of the upstream road section; determine the sub-traffic flow control amount corresponding to the intersection according to the proportion of the traffic flow into the target area at the intersection among all intersections and the traffic flow control amount; determine the total allowable traffic volume entering the intersection according to the sum of the sub-traffic flow control amount and the allowable number of queuing vehicles.

[0088] S305: For each candidate signal timing plan, determine the absolute value of the difference between the traffic capacity parameter corresponding to the candidate signal timing plan and the total allowable traffic volume entering the intersection; determine the signal timing plan corresponding to the intersection at the congestion level according to the candidate signal timing plan with the smallest absolute value of the difference.

[0089] Among them, determining the total allowable traffic volume entering the intersection includes:

[0090] Substitute the proportion of the traffic flow into the target area at the intersection among all intersections, the traffic flow control amount, and the allowable number of queuing vehicles into the formula Determine the total allowable traffic volume entering the intersection;

[0091] In the formula, q(c i ) is the total allowable traffic volume entering the intersection, Q in_控 is the traffic flow control amount, q si is the allowable number of queuing vehicles, s i % is the proportion of the traffic flow into the target area at the intersection, ∑s i % is the sum of the proportions of the traffic flows into the target area at all intersections, is the proportion of the traffic flow into the target area at the intersection among all intersections.

[0092] Among them, determining the traffic capacity parameter corresponding to the candidate green signal ratio includes:

[0093] Determine the saturated headway corresponding to the upstream section according to the target lane type of the upstream section and the corresponding relationship between different lane types and saturated headways preset; Substitute the number of passing vehicles and the saturated headway corresponding to the upstream section into the formula Determine the traffic capacity parameter corresponding to the candidate signal green ratio;

[0094] In the formula, Cap(i) is the traffic capacity parameter corresponding to the candidate signal green ratio, η i is the candidate signal green ratio, Δt is the preset duration, n i is the number of lanes of the upstream section, 60Δt×n i is the number of passing vehicles during the preset duration, h i is the saturated headway corresponding to the upstream section.

[0095] Among them, determining the traffic flow control volume according to the second ratio, the third traffic flow and the outgoing traffic flow includes:

[0096] Substitute the second ratio, the third traffic flow and the outgoing traffic flow into the formula Q in_控 =(1 - ρ)(V 在途 +ΔV 在途 ) - Q out , to determine the traffic flow control volume;

[0097] In the formula, Q in_控 is the traffic flow control volume, ρ is the second ratio, (V 在途 +ΔV 在途 ) is the third traffic flow, Q out is the outgoing traffic flow, V 在途 is the median traffic flow, ΔV 在途 is the preset traffic flow adjustment value.

[0098] In this application, first determine the traffic flow control volume, then for each candidate signal timing plan pre-configured at the intersection, determine the traffic capacity parameter corresponding to the candidate signal timing plan; Determine the total traffic volume allowed to enter the intersection; Finally, for each candidate signal timing plan, determine the absolute value of the difference between the traffic capacity parameter corresponding to the candidate signal timing plan and the total traffic volume allowed to enter; According to the candidate signal timing plan with the smallest absolute value of the difference, determine the signal timing plan corresponding to the intersection under the congestion level. Thereby improving the accuracy of determining the signal timing plan corresponding to the intersection under the congestion level.

[0099] In an alternative embodiment, after determining the traffic flow control volume and before determining the total traffic volume allowed to enter the intersection, the method further includes:

[0100] Obtain the preset first proportionality coefficient corresponding to the congestion level; if the traffic flow control volume is not greater than the product of the outgoing traffic flow and the preset first proportionality coefficient, keep the traffic flow control volume unchanged; otherwise, obtain the preset second proportionality coefficient corresponding to the congestion level, and use the product of the outgoing traffic flow and the preset second proportionality coefficient as the updated traffic flow control volume.

[0101] Optionally, the preset first proportionality coefficient corresponding to the severe congestion level is, for example, 1.05, the preset first proportionality coefficient corresponding to the general congestion level is, for example, 1.15, and the preset first proportionality coefficient corresponding to the slow congestion level is, for example, 1.25. The preset second proportionality coefficient corresponding to the severe congestion level is, for example, 0.4, the preset second proportionality coefficient corresponding to the general congestion level is, for example, 0.6, and the preset second proportionality coefficient corresponding to the slow congestion level is, for example, 0.8.

[0102] In this application, after determining the traffic flow control volume, obtain the preset first proportionality coefficient corresponding to the congestion level; if the traffic flow control volume is greater than the product of the outgoing traffic flow and the preset first proportionality coefficient, obtain the preset second proportionality coefficient corresponding to the congestion level, and use the product of the outgoing traffic flow and the preset second proportionality coefficient as the updated traffic flow control volume. Thus, the determined traffic flow control volume is more accurate.

[0103] In this application, the method for determining the signal light timing plan corresponding to the intersection at the congestion level according to the candidate signal light timing plan with the smallest absolute value of the difference includes:

[0104] If the fourth ratio of the absolute value of the difference to the total traffic volume allowed to enter the intersection is greater than the preset ratio threshold, and the traffic capacity parameter is greater than the total traffic volume allowed to enter, determine the traffic capacity gap value according to the difference between the traffic capacity parameter and the total traffic volume allowed to enter;

[0105] According to the traffic capacity gap value and the formula Determine the green signal ratio adjustment amount; update the signal light timing plan according to the green signal ratio adjustment amount;

[0106] In the formula, Δη i is the green signal ratio adjustment amount, ΔGap(i) is the traffic capacity gap value, Δt is the preset duration, and h i is the saturated headway corresponding to the upstream section.

[0107] In this application, after determining the total traffic volume allowed to enter the intersection, before determining the absolute value of the difference between the traffic capacity parameter corresponding to the candidate signal light timing plan and the total traffic volume allowed to enter for each candidate signal light timing plan, the method further includes:

[0108] If the intersection is a first-level intersection upstream of the target area, keep the total traffic flow allowed to enter the intersection unchanged;

[0109] If the intersection is a non-first-level intersection upstream of the target area, determine the fourth traffic flow that the upstream road section associated with the intersection merges into the intersection within a preset first time period, and the fifth ratio of the fifth traffic flow that merges into the target area in the fourth traffic flow. Determine the updated total traffic flow allowed to enter the intersection according to the product of the fifth ratio and the total traffic flow allowed to enter the intersection;

[0110] Among them, the first-level intersection refers to an intersection connected to the target area by one road section.

[0111] In this application, for a first-level intersection upstream of the target area, determine the total traffic flow allowed to enter the intersection according to the sum of the sub-traffic flow control volume corresponding to the intersection and the number of vehicles allowed to queue; if the intersection is a non-first-level intersection upstream of the target area, according to the fourth traffic flow that the upstream road section associated with the intersection merges into the intersection, and the fifth ratio of the fifth traffic flow that merges into the target area in the fourth traffic flow, determine the updated total traffic flow allowed to enter the intersection according to the product of the fifth ratio and the total traffic flow allowed to enter the intersection determined above. Thus, the determination of the total traffic flow allowed to enter is more accurate. It should be noted that if there are multiple first-level intersections, for each first-level intersection, determine the total traffic flow allowed to enter the intersection according to the sum of the sub-traffic flow control volume corresponding to the intersection and the number of vehicles allowed to queue. Then, for a non-first-level intersection upstream of the target area, determine the total traffic flow allowed to enter the non-first-level intersection according to the product of the fifth ratio determined for the non-first-level intersection and the total traffic flow allowed to enter the first-level intersection downstream of the non-first-level intersection.

[0112] In an optional implementation manner, the process of determining each intersection upstream of the target area includes:

[0113] For each candidate intersection within a preset range area upstream of the target area, determine the sixth traffic flow that the upstream road section associated with the candidate intersection merges into the intersection within a preset second time period, and the sixth ratio of the seventh traffic flow that merges into the target area in the sixth traffic flow. If the sixth ratio is less than a preset ratio threshold, filter out the candidate intersection; otherwise, determine the candidate intersection as an intersection upstream of the target area.

[0114] Among them, for intersections of different levels, the corresponding preset ratio thresholds can be different. For example, the preset ratio threshold corresponding to a first-level intersection is 10%, and the preset ratio threshold corresponding to an intersection of the second level or above is 20%, etc.

[0115] In this application, each intersection within a preset range area upstream of the target area is regarded as a candidate intersection, and the candidate area with a large traffic flow merging into the target area is determined as the intersection upstream of the target area. Then, the signal timing plan for the upstream intersection is configured and adjusted, thereby improving the pertinence and accuracy of signal control.

[0116] Figure 4 It is a traffic signal control framework diagram provided for this application, including traffic big data analysis, pre-event - strategy plan recommendation, and in-event - strategy plan execution and update.

[0117] Traffic big data analysis includes: obtaining the traffic flow between the origin and destination (or called the channel OD), traffic traceability, traffic prediction, and traffic indicators.

[0118] Pre-event - strategy plan recommendation includes: control object recognition, traffic state critical value and management level definition, control strategy recommendation, and control plan calculation.

[0119] In-event - strategy plan execution and update includes:

[0120] Matching the management level (congestion level), recommending control strategies and plans, comparing the congestion index of each control point (intersection) with that in the target area every 5 minutes, judging whether the congestion index upstream of control point i is greater than the congestion index in the target area. If so, judging whether control point i is executing the recommended plan. If so, the control point restores the default configuration plan before the recommendation. If not, the control point does not execute the recommended plan. When the congestion index upstream of control point i is not greater than the congestion index in the target area, the control point executes the recommended plan, and judges whether the congestion level of the target area reaches the expectation. If it reaches the expectation, continue to monitor. If it does not reach the expectation, feedback and adjust the control plan, and upgrade or downgrade the management level.

[0121] Figure 5 It is a process schematic diagram for generating a strategy plan provided for this application, as Figure 5 shown, input the regulation object or system recommendation to determine the regulation object; input the regulation state or system recommendation to determine the regulation state; conduct traceability analysis to determine the regulation strategy; manually edit the strategy plan to generate the strategy plan.

[0122] 1.1. Determine the regulation object.

[0123] Determine the regulation object by the way of user demarcation. The regulation object refers to the target area, or called the core area.

[0124] 1.2. Determine the regulation state.

[0125] 1.2.1. Core area traffic state indicators.

[0126] A combination of multiple key indicators in different dimensions {number of vehicles on the road in the region, regional congestion index} is used to determine the congestion status of the core area. If any indicator reaches the threshold, an early warning will be issued and a control plan will be recommended.

[0127] Based on the historical congestion index and the number of vehicles on the road, the macro basic map of the region can be drawn to obtain the threshold value Qn of the number of vehicles on the road in the region. The following thresholds are recommended values, and the thresholds can be adjusted on site according to actual conditions.

[0128] Table 1 - Core area status indicators and threshold recommendations

[0129] Core area status threshold Unobstructed - Ⅳ Slow - moving - Ⅲ Congested - Ⅱ Severely congested - Ⅰ Total number of vehicles in transit at any given moment ≤Q1 (Q1, Q2] (Q2, Q3] ≥Q3 Regional congestion index ≤1.4 (1.4，1.7] (1.7，1.9] ≥1.9

[0130] 1.2.2. Determine the recommended timing for starting / ending the control plan.

[0131] 1. Basic constraints.

[0132] 1) All control plans are started / ended. The system supports automatic recommendation, but does not start or end automatically. Execution / end or non-execution starts after manual confirmation.

[0133] 2) The start and end states of the control object can be customized, and the default is the system recommendation.

[0134] 2. Recommendation on starting / ending the control object.

[0135] Key indicators: core area congestion index, number of vehicles on the road, any control level value reached, start judgment and report to the system. (Unified with the mid-event update)

[0136] Table 2-Trigger conditions for recommended solutions

[0137] Indicator Congestion index Number of vehicles in transit System report 1 Warning No Yes, it is recommended to initiate the regulation plan 2 Warning Warning Yes, it is recommended to initiate the regulation plan 3 No Warning Yes, it is recommended to initiate the regulation plan

[0138] 1.3 Peripheral channel flow control method.

[0139] 1.3.1 Identification of key entry paths based on traceability analysis.

[0140] The purpose of the traceability analysis is to identify the channels for vehicle demand control entering the core area and the channels for leaving the core area, and to support the recommendation of control strategies and control intersection solutions. The date and time period for formulating control strategies as needed, such as weekdays and evening peak hours, are selected to perform traceability analysis data in the area.

[0141] According to the traceability analysis input: the number of vehicles arriving at the core area from the outer sections of the core area d i , the ratio of the traffic volume flowing into the core area from the upstream section associated with the intersection to the traffic volume flowing into the intersection from the upstream section associated with the intersection d i %, Total number of traceable vehicles in the core area D 入核心区. Calculate the following content:

[0142] (1) Vehicle inflow and inflow ratio at the key entrance nodes (intersections): s i , s i %, retain the nodes where s i % ≥ 10%, {s1, … s n}; Node inflow value: ① The number of vehicles on the road section where the node is located in the traceability result, and calculate the inflow ratio; ② Enter the node flow, and calculate the inflow ratio.

[0143] Associate the upstream intersections of the key entrance nodes as the starting intersections of the alternative control channels and include them in the set of starting intersections {c1, … c n}; The inflow of the key entrance nodes is the traceability inflow of the first-level starting intersection set {d ci , … d cn}.

[0144] (2) Conduct traceability analysis on the upstream road sections of each first-level intersection in turn to determine the main traffic flow directions:

[0145] First step: Screen according to the proportion of vehicles reaching the core area traced by the upstream road section. d i %, d i % < 10% when the traceability analysis terminates, and the set of road section-intersections forming the traceability path are all continuous paths reaching the first-level starting intersections.

[0146] Second step: Screen according to the proportion of the number of vehicles flowing into the downstream intersection from the upstream road section. Starting from the first-level starting intersection, calculate the proportion of the traced vehicles on the upstream associated road section to the traced vehicles on the downstream road section of the downstream intersection. Figure 6 This is the traceability schematic diagram provided by this application. As Figure 6 shown, taking intersection C3 as an example, Retain the proportion For each intersection, retain the upstream associated road section with the largest proportion, or at most retain two road sections with an upstream association greater than the proportion threshold. Each road section has a corresponding traffic signal light, and this application can process each road section separately. Update the set of traceability path-intersections, which are all continuous paths reaching the first-level starting intersections.

[0147] (3) Identify the upstream key paths of each first-level intersection.

[0148] First-level intersection C1.

[0149] Key path 1: First-level intersection (traffic flow inflow ratio) - associated road section (enter the turn, inflow ratio into the downstream intersection) - second-level intersection - associated road section (enter the turn, inflow ratio into the downstream intersection), etc.

[0150] Critical Path 2: Primary intersections (proportion of vehicle flow merging) - associated road sections (entering turns, proportion of vehicles merging into downstream intersections) - secondary intersections - associated road sections (entering turns, proportion of vehicles merging into downstream intersections), etc.

[0151] 1.3.2 Calculation of the total inflow control volume into the area.

[0152] 1. Control objectives.

[0153] After the implementation of the regional traffic control plan, the number of vehicles in transit within the region remains stable: ① Controlling the inflow based on the outflow to achieve dynamic balance of vehicles in transit internally; ② Delaying the entry time of the increasing volume into the area to prevent a rapid rise in congestion within the area.

[0154] 2. Control period: 15 minutes.

[0155] 3. Calculation of the inflow traffic control volume Q into the area in_控 .

[0156] Q in_控 = (1 - ρ)(V 在途 + ΔV 在途 ) - Q out ;

[0157] And it should meet the following conditions,

[0158] Otherwise, Q in_控 = αQ out , and the value of α is determined according to the following table:

[0159] Coefficient α Level 3 - Slow - moving Level 2 - Congested Level 1 - Severely congested Value 0.8 0.6 0.4

[0160] Where:

[0161] V 在途 , the number of vehicles in transit in the core area, taking the median value of the corresponding regulation level interval of the current plan.

[0162] ΔV 在途 , the amount of vehicles in transit that can be moderately increased or decreased under the current regulation level.

[0163] When the traffic is slow, ΔV 在途 = 0.25(V max - V min ); When the traffic is congested, ΔV 在途 = -0.5(V max - V min ), When the traffic is severely congested, ΔV 在途 = -1.25(V max - V min );

[0164] Q out, the total number of vehicles driving out of the core area, collect the driving flow at key nodes entering the area; accumulate the driving-out data during the tracing period every 15 minutes, calculate it rolling every 5 minutes, and take the 50% percentile value. For example, the driving-out data from 8:00 to 8:15 in the tracing core area, the driving-out data from 8:05 to 8:20, the driving-out data from 8:10 to 8:25, the driving-out data from 8:15 to 8:30, etc. In this way, multiple driving-out data can be obtained, and then the median data among these driving-out data is used as Q out ;

[0165] ρ, the proportion of internal vehicles among the vehicles on the way, is determined according to the on-site data analysis results.

[0166] 1.3.3. Calculation of the flow-limiting control scheme for the peripheral channels.

[0167] According to the allowable entry volume at the intersection on the regional boundary, control the flow step by step outward, and consider the queue length constraints at each intersection.

[0168] 1. Calculation of the scheme for the first-level intersections.

[0169] ① Select the scheme for the first-level intersections.

[0170] Calculation of the green signal ratio for the control of the first-level starting intersection

[0171] Calculation of the total allowable entry volume at the first-level starting intersection:

[0172] Among them, the allowable number of queuing vehicles on the upstream section of the key node entering the area l si is the road section length, and ni is the number of lanes in the direction of entering the area on the road section.

[0173] Calculate the traffic capacity of the first direction of the road section entered by each scheme at the starting intersection: Optionally, various timing schemes between 7:00 - 19:00 can be selected.

[0174] h i : the saturated headway for straight, left turn, straight-left, straight-right, and U-turn left; n i is the number of lanes of the associated road section 1 entering the downstream intersection; Δt is the time granularity for calculating the entry control volume into the area, with a default of 15 minutes.

[0175] Lane type Saturation flow rate (per hour) Saturation headway (seconds) Left turn + U - turn 1250 2.88 Left turn 1350 2.67 Straight + left turn or right turn 1350 2.67 Branch road straight 1450 2.48 Sub - arterial road straight 1600 2.25 Main arterial road straight 1800 2.00

[0176] It should be noted that if there are multiple lane types on the upstream road, hi can take the average value of the saturated headways corresponding to multiple lane types.

[0177] Select the scheme with the smallest difference from the allowable entry flow, min{|Cap(i)-q(ci )|}, select the one with a larger cycle when there are multiple solutions.

[0178] ② Calibrate the solution for selecting a first-level intersection.

[0179] When and Cap(i)>q(c i ), correct the selected solution, otherwise do not correct. The correction method is as follows:

[0180] Calculate the traffic capacity gap: ΔCap = Cap(i)-q(c i ), then the green signal ratio to be corrected: When there are multiple phases, take the average value of hi.

[0181] Compress the phases without changing the cycle. In the case of multiple phases, compress according to the ratio of the original solution.

[0182] 2. Calculate the solutions for other-level intersections.

[0183] According to the actual on-site requirements, the control flow requirements of the first-level control intersections can be traced upstream by 3-5 levels for optimizing the solutions of other intersections.

[0184] Take Figure 6 as an example, calculate the entering control flow of the second-level intersection:

[0185]

[0186] Calculate the control flow of the associated sections of the second-level intersection:

[0187]

[0188] Then calculate each Cap(i). After calculating q(ci) and Cap(i), calculate the green signal ratio. The same as above, it will not be elaborated.

[0189] Figure 7 This is the flowchart for the execution and update of the strategy solution provided by this application, as Figure 7As shown, according to the status prediction value, trigger the pre-plan control to determine the pre-plan level; adjust and distribute the plan under the control strategy; compare the congestion index of each control point with that in the target area every 5 minutes; judge whether the congestion index upstream of control point i is greater than the congestion index in the target area. If so, judge whether control point i is executing the recommended plan. If so, the control point resumes the default configuration plan before the recommendation. If not, the control point does not execute the recommended plan. If the congestion index upstream of control point i is not greater than the congestion index in the target area, the control point executes the recommended plan, and judge whether the congestion level of the target area reaches the expectation, that is, judge whether the actual inflow is not greater than the expected inflow. If it reaches the expectation, judge whether to trigger the pre-plan downgrade. If not, feedback and adjust the current control pre-plan. If so, judge whether to trigger the pre-plan. If the pre-plan is triggered, trigger the pre-plan control to determine the pre-plan level. If the pre-plan is not triggered, resume the default configuration plan before the recommendation. If it does not reach the expectation, judge whether to upgrade the pre-plan. If not, feedback and adjust the current control pre-plan. If so, trigger the pre-plan control to determine the pre-plan level.

[0190] 2.1. Recommended Strategy Plan during Congestion Occurrence (Peripheral Channels).

[0191] Corresponding Business Function: When it is predicted that congestion is about to occur, match the corresponding control strategy and plan, and make differential adjustments.

[0192] Conditions:

[0193] 1. The prevention and control pre-plan levels are divided into 4 levels. The smaller the value, the higher the level, and the greater the traffic control intensity.

[0194] 2. The preset pre-plan needs to have status point thresholds, control strategy plans, and record the historical inflow / outflow traffic (or traffic ratio) of each corresponding channel.

[0195] 3. It can predict the element values in the status point set {number of vehicles in transit in the area, congestion index in the area, number of key congestion nodes in the area}, and channel traffic.

[0196] 4. The expected traffic volume to flow into each control channel.

[0197] 5. Define the traffic control ratio as the reduced ratio based on the green signal ratio of the original basic plan. That is: λ 控流比 =(η0 - η) / η0.

[0198] η is the green signal ratio = g / C. g is the green light duration of the phase, and C is the intersection signal cycle.

[0199] (1) Obtain the predicted traffic status set I (the status threshold is composed of multiple traffic monitoring points in different dimensions {number of vehicles in transit in the area, congestion index in the area}), and determine the element values in the traffic status set that trigger control.

[0200] For example, the predicted traffic state set I = {5842, 1.8}.

[0201] (2) During the same time period, match the elements in the predicted traffic state set with the elements of the traffic state range threshold set in the preset pre - plan library. According to the principle of taking the smaller value for different elements in the set according to the control level, determine the final pre - plan control level.

[0202] For example, 5842 matches the pre - plan level of 2; 1.8 matches the pre - plan level of 3; then the final selected pre - plan level is 2, and the level - 2 control pre - plan is selected.

[0203] (3) After determining the control level, obtain the control intersections corresponding to the level; if the congestion index (travel time ratio) of the upstream section corresponding to the control intersection i > the congestion index (travel time ratio) of the management and control area, then the control plan at intersection i stops running, otherwise directly run the management and control plan corresponding to the control level.

[0204] 2.2 Dynamic update during the plan execution process (peripheral channels).

[0205] After running the strategy plan corresponding to the new control threshold for 5 minutes, if there is no switching of the management and control level, the following plan update is carried out, and the update frequency is 5 minutes. The logic is as follows:

[0206] ① When the congestion index (travel time ratio) of the upstream section corresponding to the control intersection i > the congestion index (travel time ratio) of the management and control area, then the control at intersection i stops, and the original plan is restored, and the following plan update logic is no longer carried out; until the congestion index (travel time ratio) of the upstream section > the congestion index (travel time ratio) of the management and control area, then the control plan at intersection i runs.

[0207] Let the in - transit thresholds corresponding to levels 1, 2, and 3 be Q1, Q2, and Q3 respectively.

[0208] ② When the currently running management and control level is level 1, obtain the green - signal ratio time g and cycle C of the control direction corresponding to the plan currently running at the intersection, and predict the in - transit vehicles Q in the next 5 minutes i ;

[0209] If Q i > Q1+(Q1 - Q2) / 100, the green - signal ratio time of the corresponding intersection control direction is updated to g i1 = g0 - min(int(Q i - Q1) / 100, 3), and the durations of other directions remain unchanged; when g i1 < the minimum green - light duration g min , calculate △g = g min - g i1 ; let g i1 = g min, corresponding to a cycle of C i = C + Δg, and the time of other stages is proportionally allocated with Δg.

[0210] Otherwise, no scheme update is performed.

[0211] ③ When the running control level is level 2, obtain the green signal ratio time g and cycle C of the corresponding control direction of the intersection's running scheme, and predict the in - transit vehicles in the next 5 minutes as Q i ;

[0212] If Q2 < Q i < Q1, obtain the green signal ratio time and cycle of the corresponding control direction in the configuration strategy scheme when the control thresholds are level 2 and level 1. Respectively, for level 2, they are g2 and C2, and for level 1, they are g1 and C1;

[0213] When g2 / C2 ≤ g1 / C1, no scheme update is performed;

[0214] When the level - 1 controlled intersection cannot be obtained, no scheme update is performed for the corresponding intersection scheme;

[0215] Let the green signal ratio of the updated scheme control direction be λ i , according to the corresponding relationship between the control level and the control scheme, there is:

[0216]

[0217] Calculate λ according to the above formula i , when λ i ≤ g1 / C1, then λ i = g1 / C1.

[0218] When the cycle duration of the running scheme is not changed, then:

[0219]

[0220] When it is calculated that g i2 < g min , then take g i2 = g min , and inversely deduce the recommended cycle duration according to the traffic control ratio requirement, the increased time, and the other stages are proportionally allocated according to the running scheme.

[0221] Otherwise, no scheme update is performed.

[0222] ④ When the running control level is level 3, obtain the green signal ratio time g and cycle C of the corresponding control direction of the intersection's running scheme, and predict the in - transit vehicles in the next 5 minutes as Q i ;

[0223] If Q3 < Q iWhen it is less than Q2 and obtaining the control thresholds of level 3 and level 2, obtain the green signal ratio time and cycle corresponding to the control direction in the corresponding configuration strategy plan, which are g3 and C3 for level 3 respectively, and g2 and C2 for level 2 respectively;

[0224] When g3 / C3 ≤ g2 / C2, do not update the plan;

[0225] When the control intersections of level 2 cannot be obtained, do not update the plan for the corresponding intersection plan;

[0226] Let the green signal ratio of the updated plan control direction be λ i , according to the corresponding relationship between the control level and the control plan, there is:

[0227]

[0228] Calculate λ according to the above formula i , when λ i ≤ g2 / C2, then λ i = g2 / C2.

[0229] When not changing the cycle duration of the running plan, then:

[0230]

[0231] When it is calculated that g i2 < g min , then take g i2 = g min ; Reverse-infer the recommended cycle duration according to the traffic control ratio requirement, and increase the time, and other phases are allocated proportionally according to the running plan.

[0232] Otherwise, do not update the plan.

[0233] Figure 8 is the schematic diagram of the pre-event - strategy plan recommendation interface provided by this application. As Figure 8 shown, it includes a map display area, a monitoring object selection display area, a core area display area in the map, a warning level threshold recommendation display area, a preview of the strategy sub-areas preferred by different control levels, and a recommended display area of the control intersection plans at all levels.

[0234] Figure 9 is the schematic diagram of the in-event - real-time traceability and prediction interface provided by this application. As Figure 9As shown in the figure, it includes the monitoring and display area of the core area traffic operation status, the monitoring and display area of the currently executing policy plan, the map display area, the core area display area in the map, and the current / predicted display area of the number of vehicles in transit in the core area. The map display area shows the key inbound paths obtained based on real-time tracing, the current number of inbound and outbound vehicles in each channel, and the predicted number of inbound and outbound vehicles in each channel. The monitoring and display area of the core area traffic operation status shows the current values and trend charts of the number of vehicles in transit & congestion index. The monitoring and display area of the currently executing policy plan shows the execution time and plan adjustment. The current / predicted display area of the number of vehicles in transit in the core area shows the number of vehicles in transit in the core area, the trend chart of the number of inbound and outbound vehicles; as well as the current / predicted number of vehicles and vehicle occupancy rate on each key inbound path.

[0235] Figure 10 This is a schematic diagram of the interface for in-process congestion warning and plan recommendation provided by the present application. As Figure 10 shown in the figure, it includes the monitoring and display area of the core area traffic operation status, the monitoring and display area of the currently executing policy plan, the map display area, the core area display area in the map, and the display area for recommending the traffic control plan corresponding to the current warning level. The map display area gives a warning when the congestion level changes, and the recommended intersection plan can be viewed / executed; and it shows the recommended green light duration and the original duration in the traffic control direction of each level of intersection; as well as the pre-configured traffic control intersections. The monitoring and display area of the core area traffic operation status shows the current values and trend charts of the number of vehicles in transit & congestion index. The monitoring and display area of the currently executing policy plan shows the execution time and plan adjustment. The display area for recommending the traffic control plan corresponding to the current warning level shows the control sub-area, control intersections, traffic control plan, and original plan.

[0236] Figure 11 This is a schematic diagram of the interface for in-process plan adaptive adjustment provided by the present application. As Figure 11 shown in the figure, it includes the monitoring and display area of the core area traffic operation status, the monitoring and display area of the currently executing policy plan, the map display area, the core area display area in the map, and the display area for adaptive adjustment records. The map display area shows the green light duration of the adaptive adjustment of the traffic control direction at intersections; as well as the pre-configured traffic control intersections. The monitoring and display area of the core area traffic operation status shows the current values and trend charts of the number of vehicles in transit & congestion index. The monitoring and display area of the currently executing policy plan shows the execution time and plan adjustment. The display area for adaptive adjustment records shows which intersections have adaptively adjusted the green light duration according to the predicted status of the core area and the intersection status.

[0237] Figure 12 This is a schematic diagram of the structure of the traffic signal control device provided by the present application. The device includes:

[0238] The first determination module 121 is configured to predict the first traffic flow of the target area at the first moment according to the first historical traffic flow of the target area; and determine the first congestion level corresponding to the first traffic flow range to which the first traffic flow belongs according to the traffic flow ranges corresponding to different congestion levels pre-stored.

[0239] The first control module 122 is configured to, if the first congestion level is the severe congestion level, obtain the lower boundary value of the traffic flow in the first traffic flow range, determine the first traffic flow difference between the first traffic flow and the lower boundary value of the traffic flow; determine the signal timing adjustment amount according to the first traffic flow difference; for each intersection upstream of the target area, determine the second signal timing scheme of the intersection according to the current first signal timing scheme of the intersection and the signal timing adjustment amount, and control the signal lights of the intersection according to the second signal timing scheme.

[0240] The second control module 123 is configured to, if the first congestion level is the general congestion level or the slow congestion level, obtain the upper boundary value and the lower boundary value of the traffic flow in the first traffic flow range, determine the second traffic flow difference between the first traffic flow and the lower boundary value of the traffic flow; and the third traffic flow difference between the upper boundary value and the lower boundary value of the traffic flow; for each intersection upstream of the target area, determine the difference between the green ratio of the signal lights in the third signal timing scheme corresponding to the intersection at the first congestion level and the green ratio of the signal lights in the fourth signal timing scheme corresponding to the intersection at the previous congestion level of the first congestion level; determine the fifth signal timing scheme of the intersection according to the first ratio of the second traffic flow difference to the third traffic flow difference and the difference, and control the signal lights of the intersection according to the fifth signal timing scheme.

[0241] Wherein, the previous congestion level of the slow congestion level is the general congestion level, and the previous congestion level of the general congestion level is the severe congestion level; the traffic flow range corresponding to the slow congestion level includes traffic flow values smaller than the traffic flow range corresponding to the general congestion level, and the traffic flow range corresponding to the general congestion level includes traffic flow values smaller than the traffic flow range corresponding to the severe congestion level.

[0242] The device further includes:

[0243] The second determination module 124 is further configured to predict the second traffic flow of the target area at the second moment according to the second historical traffic flow of the target area; and determine the second congestion level corresponding to the second traffic flow range to which the second traffic flow belongs according to the traffic flow ranges corresponding to different congestion levels pre-stored.

[0244] The third control module 125 is configured to, for each intersection upstream of the target area, determine a sixth signal timing plan corresponding to the intersection at the second congestion level according to the pre-determined signal timing plans corresponding to the intersection at each congestion level; and control the traffic signal lights of the intersection according to the sixth signal timing plan.

[0245] The third control module 125 is further configured to, for each congestion level, determine the signal timing plan corresponding to the intersection at the congestion level through the following steps: obtain the preset traffic flow adjustment value corresponding to the congestion level, and determine the median traffic flow of the traffic flow range corresponding to the congestion level; determine the outgoing traffic flow of the target area within a historical time period; determine the third traffic flow within the target area according to the median traffic flow and the traffic flow adjustment value; determine the second ratio of the number of internal driving vehicles monitored within the target area to the total number of driving vehicles monitored within the historical time period, and determine the traffic flow control amount according to the second ratio, the third traffic flow, and the outgoing traffic flow; determine the number of lanes leading to the target area on the upstream road section associated with the intersection according to the lane directions of each lane of the upstream road section associated with the intersection; for each candidate signal timing plan pre-configured for the intersection, determine the number of passing vehicles within a preset duration according to the number of lanes and the green signal ratio of the signal lights in the candidate signal timing plan; determine the passing capacity parameter corresponding to the candidate signal timing plan according to the third ratio of the number of passing vehicles and the saturated headway corresponding to the upstream road section; determine the allowable queuing vehicle number of the upstream road section according to the number of lanes leading to the target area on the upstream road section associated with the intersection and the length of the upstream road section; determine the sub-traffic flow control amount corresponding to the intersection according to the proportion of the traffic flow convergence ratio of the intersection entering the target area among all intersections and the traffic flow control amount; determine the total allowable incoming traffic flow of the intersection according to the sum of the sub-traffic flow control amount and the allowable queuing vehicle number; for each candidate signal timing plan, determine the absolute value of the difference between the passing capacity parameter corresponding to the candidate signal timing plan and the total allowable incoming traffic flow; and determine the signal timing plan corresponding to the intersection at the congestion level according to the candidate signal timing plan with the smallest absolute value of the difference.

[0246] The third control module 125 is specifically configured to substitute the second ratio, the third traffic flow, and the outgoing traffic flow into the formula Q in_控 =(1 - ρ)(V 在途 +ΔV 在途 ) - Q out to determine the traffic flow control amount;

[0247] In the formula, Q in_控 is the traffic flow control amount, ρ is the second ratio, (V在途 +ΔV 在途 ) is the third vehicle flow, Q out is the outgoing vehicle flow, V 在途 is the median of the traffic flow, ΔV 在途 is the preset vehicle flow adjustment value.

[0248] The third control module 125 is also used to obtain a preset first proportional coefficient corresponding to the congestion level; if the traffic control amount is not greater than the product of the outgoing vehicle flow and the preset first proportional coefficient, the traffic control amount is kept unchanged; otherwise, the preset second proportional coefficient corresponding to the congestion level is obtained, and the product of the outgoing vehicle flow and the preset second proportional coefficient is used as the updated traffic control amount.

[0249] The third control module 125 is specifically configured to determine a capacity gap value according to the difference between the capacity parameter and the total vehicle flow allowed to enter the intersection if a fourth ratio of the absolute value of the difference to the total vehicle flow allowed to enter the intersection is greater than a preset ratio threshold, and the capacity parameter is greater than the total vehicle flow allowed to enter; and determine a capacity gap value according to the capacity gap value and the formula Determining a green-to-signal ratio adjustment amount; updating the signal light timing plan according to the green-to-signal ratio adjustment amount;

[0250] In the formula, Δη i is the green-signal ratio adjustment, ΔGap(i) is the capacity gap value, Δt is the preset time length, h i is the saturated headway time corresponding to the upstream section.

[0251] The third control module 125 is also used to keep the total vehicle flow allowed to enter the intersection unchanged if the intersection is a first-level intersection upstream of the target area; if the intersection is a non-first-level intersection upstream of the target area, determine a fifth ratio of a fourth vehicle flow rate entering the intersection from an upstream section associated with the intersection within a preset first time period to a fifth vehicle flow rate from the fourth vehicle flow rate entering the target area, and determine an updated total vehicle flow rate allowed to enter based on the product of the fifth ratio and the total vehicle flow rate allowed to enter the intersection; wherein the first-level intersection refers to an intersection connected to the target area by a section.

[0252] The first control module 122 is specifically used for i >Q1+(Q1-Q2) / 100, the green light duration in the second signal light timing scheme of the intersection is determined to be g i1 =g0-min(int(Q i -Q1) / 100,3); where min(int(Q i-Q1) / 100, where 3) is the timing adjustment amount of the signal light; when g i1 <g min calculate Δg = g min -g i1 ; let g i1 = g min to determine that the cycle length in the second signal timing plan for the intersection is C i = C + Δg; where Q i is the first traffic flow, Q1 is the lower boundary value of the traffic flow in the traffic flow range corresponding to the severe congestion level, Q2 is the lower boundary value of the traffic flow in the traffic flow range corresponding to the general congestion level, g i1 is the green light duration in the second signal timing plan, g0 is the green light duration in the current first signal timing plan, g min is the minimum green light duration configured for the intersection, C is the cycle length in the current first signal timing plan, and C i is the cycle length in the second signal timing plan.

[0253] The second control module 123 is specifically configured to, if the first congestion level is the general congestion level, calculate the green signal ratio λ according to the formula, when λ i ≤ g1 / C1, take λ i = g1 / C1; when not changing the signal light cycle length, then: i When it is calculated that g <g i2 min take g i2 = g min ; In the formula, g2 is the green light duration in the third signal timing plan corresponding to the pre-determined general congestion level, c2 is the cycle length in the third signal timing plan corresponding to the pre-determined general congestion level, g1 is the signal light cycle length in the fourth signal timing plan corresponding to the pre-determined severe congestion level, c1 is the cycle length in the fourth signal timing plan corresponding to the pre-determined severe congestion level, and g i2 i is the green light duration in the fifth signal timing plan;

[0254] If the first congestion level is the slow congestion level, calculate the green signal ratio λ according to the formula, when λ i ≤ g2 / C2, take λ i = g2 / C2; when not changing the signal light cycle length, then: i When it is calculated that g <g i2 min take g i2 = g min ​; where \(g_3\) is the green light duration in the third signal timing plan corresponding to the pre-determined slow traffic congestion level, \(c_3\) is the cycle duration in the third signal timing plan corresponding to the pre-determined slow traffic congestion level, \(g_2\) is the green light duration in the fourth signal timing plan corresponding to the pre-determined general congestion level, \(c_2\) is the cycle duration in the fourth signal timing plan corresponding to the pre-determined general congestion level, and \(g\) i2 is the green light duration in the fifth signal timing plan.

[0255] The first determination module 121 is further configured to determine, for each candidate intersection within a preset range area upstream of the target area, the sixth traffic flow ratio between the sixth traffic flow entering the intersection from the upstream road section associated with the candidate intersection within a preset second time period and the seventh traffic flow entering the target area among the sixth traffic flow. If the sixth traffic flow ratio is less than a preset ratio threshold, the candidate intersection is filtered out; otherwise, the candidate intersection is determined as the intersection upstream of the target area.

[0256] This application also provides an electronic device, as Figure 13 shown, including: a processor 131, a communication interface 132, a memory 133, and a communication bus 134. Among them, the processor 131, the communication interface 132, and the memory 133 communicate with each other through the communication bus 134;

[0257] The computer program is stored in the memory 133. When the program is executed by the processor 131, the processor 131 is caused to execute any of the above method steps.

[0258] The communication bus mentioned in the above electronic device may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of simplicity, only a thick line is shown in the figure, but it does not mean that there is only one bus or one type of bus.

[0259] The communication interface 132 is used for communication between the above electronic device and other devices.

[0260] The memory may include a Random Access Memory (RAM), and may also include a Non-Volatile Memory (NVM), such as at least one disk memory. Optionally, the memory may also be at least one storage device located far from the aforementioned processor.

[0261] The above-mentioned processor may be a general-purpose processor, including a central processing unit, a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit, a field programmable gate array, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0262] The present application also provides a computer-readable storage medium, in which a computer program executable by an electronic device is stored. When the program runs on the electronic device, the electronic device is caused to execute any of the above method steps.

[0263] The present application provides a computer program product, the computer program product includes an executable program, and when the executable program is executed by a processor, the method is implemented.

[0264] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present application.

[0265] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A traffic signal control method, characterized in that, The method includes: Predicting the first traffic flow of the target area at the first moment according to the first historical traffic flow of the target area; determining the first congestion level corresponding to the first traffic flow range where the first traffic flow belongs according to the traffic flow ranges corresponding to different congestion levels stored in advance; If the first congestion level is the severe congestion level, obtaining the traffic flow lower boundary value of the first traffic flow range, determining the first traffic flow difference between the first traffic flow and the traffic flow lower boundary value; determining the signal timing adjustment amount according to the first traffic flow difference; for each intersection upstream of the target area, determining the second signal timing plan of the intersection according to the current first signal timing plan of the intersection and the signal timing adjustment amount, and controlling the traffic lights of the intersection according to the second signal timing plan; If the first congestion level is the general congestion level or the slow congestion level, obtaining the traffic flow upper boundary value and the traffic flow lower boundary value of the first traffic flow range, determining the second traffic flow difference between the first traffic flow and the traffic flow lower boundary value; and the third traffic flow difference between the traffic flow upper boundary value and the traffic flow lower boundary value; for each intersection upstream of the target area, determining the difference between the signal green ratio in the third signal timing plan corresponding to the intersection at the first congestion level and the signal green ratio in the fourth signal timing plan corresponding to the intersection at the previous congestion level of the first congestion level; determining the fifth signal timing plan of the intersection according to the first ratio of the second traffic flow difference to the third traffic flow difference and the difference, and controlling the traffic lights of the intersection according to the fifth signal timing plan; Wherein, the previous congestion level of the slow congestion level is the general congestion level, and the previous congestion level of the general congestion level is the severe congestion level; the traffic flow range corresponding to the slow congestion level includes traffic flow values smaller than the traffic flow range corresponding to the general congestion level, and the traffic flow range corresponding to the general congestion level includes traffic flow values smaller than the traffic flow range corresponding to the severe congestion level.

2. The method according to claim 1, wherein Before predicting the first traffic flow of the target area at the first moment according to the first historical traffic flow of the target area, the method further includes: Predicting the second traffic flow of the target area at the second moment according to the second historical traffic flow of the target area; determining the second congestion level corresponding to the second traffic flow range where the second traffic flow belongs according to the traffic flow ranges corresponding to different congestion levels stored in advance; For each intersection upstream of the target area, determining the sixth signal timing plan corresponding to the intersection at the second congestion level according to the signal timing plans corresponding to the intersection at each congestion level determined in advance; controlling the traffic lights of the intersection according to the sixth signal timing plan.

3. The method according to claim 2, wherein The process of determining the signal timing plans corresponding to the intersection at each congestion level in advance includes: For each of the congestion levels, the signal timing plan corresponding to the intersection at the congestion level is determined through the following steps: Obtain the preset traffic flow adjustment value corresponding to the congestion level, and determine the median traffic flow within the traffic flow range corresponding to the congestion level; determine the outgoing traffic flow of the target area within the historical time period; based on the median traffic flow and the traffic flow adjustment value, determine the third traffic flow within the target area; determine the second ratio of the number of internal driving vehicles monitored within the target area to the total number of driving vehicles monitored within the historical time period, and based on the second ratio, the third traffic flow, and the outgoing traffic flow, determine the traffic flow control volume; Based on the lane directions of each lane of the upstream road section associated with the intersection, determine the number of lanes leading to the target area on the upstream road section; for each candidate signal timing plan pre-configured for the intersection, based on the number of lanes and the green signal ratio of the signals in the candidate signal timing plan, determine the number of passing vehicles within the preset duration; based on the third ratio of the number of passing vehicles and the saturated headway corresponding to the upstream road section, determine the passing capacity parameter corresponding to the candidate signal timing plan; Based on the number of lanes leading to the target area on the upstream road section associated with the intersection and the length of the upstream road section, determine the allowable number of queuing vehicles on the upstream road section; based on the proportion of the traffic flow merging ratio of the intersection entering the target area among all intersections and the traffic flow control volume, determine the sub-traffic flow control volume corresponding to the intersection; based on the sum value of the sub-traffic flow control volume and the allowable number of queuing vehicles, determine the total allowable traffic flow entering the intersection; For each of the candidate signal timing plans, determine the absolute value of the difference between the passing capacity parameter corresponding to the candidate signal timing plan and the total allowable traffic flow entering; based on the candidate signal timing plan with the smallest absolute value of the difference, determine the signal timing plan corresponding to the intersection at the congestion level.

4. The method according to claim 3, characterized in that, Determining the traffic flow control volume based on the second ratio, the third traffic flow, and the outgoing traffic flow includes: Substitute the second ratio, the third traffic flow, and the outgoing traffic flow into the formula Q in_控 =(1-ρ)(V 在途 +ΔV 在途 )-Q out , and determine the traffic flow control volume; where Q in_控 is the traffic flow control volume, ρ is the second ratio, (V 在途 +ΔV 在途 ) is the third traffic flow, Q out is the traffic flow out of the vehicle, V 在途 is the median value of the traffic flow, and ΔV 在途 is the preset traffic flow adjustment value.

5. The method according to claim 3 or 4, characterized in that After determining the traffic flow control volume and before determining the total allowable traffic flow entering the intersection, the method further includes: Obtain the preset first proportionality coefficient corresponding to the congestion level; if the traffic flow control volume is not greater than the product of the outgoing traffic flow and the preset first proportionality coefficient, keep the traffic flow control volume unchanged; otherwise, obtain the preset second proportionality coefficient corresponding to the congestion level, and use the product of the outgoing traffic flow and the preset second proportionality coefficient as the updated traffic flow control volume.

6. The method according to claim 3, characterized in that Determining the signal timing plan corresponding to the intersection at the congestion level based on the candidate signal timing plan with the smallest absolute value of the difference includes: If the fourth ratio of the absolute value of the difference to the total allowable traffic flow entering the intersection is greater than the preset proportionality threshold, and the passing capacity parameter is greater than the total allowable traffic flow entering, determine the passing capacity gap value based on the difference between the passing capacity parameter and the total allowable traffic flow entering; Based on the traffic capacity gap value and the formula Determine the green signal ratio adjustment amount; update the signal timing plan according to the green signal ratio adjustment amount; where Δη i is the adjusted value of the green signal ratio, ΔGap(i) is the value of the capacity gap, Δt is the preset duration, and h i is the saturated headway corresponding to the upstream section.

7. The method according to claim 3, wherein Before determining the absolute value of the difference between the traffic capacity parameter corresponding to the candidate signal timing plan and the total allowable traffic volume entering the intersection after determining the total allowable traffic volume entering the intersection, the method further includes: If the intersection is a first-level intersection upstream of the target area, keep the total allowable traffic volume entering the intersection unchanged; If the intersection is a non-first-level intersection upstream of the target area, determine the fourth traffic volume flowing into the intersection from the upstream road section associated with the intersection within a preset first time period, and the fifth ratio of the fifth traffic volume flowing into the target area among the fourth traffic volume, and determine the updated total allowable traffic volume entering the intersection according to the product of the fifth ratio and the total allowable traffic volume of the intersection; Wherein, the first-level intersection refers to an intersection connected to the target area through a road section.

8. The method according to claim 1, wherein Determining the second signal timing plan of the intersection according to the current first signal timing plan of the intersection and the signal timing adjustment amount includes: If Q i > Q1 + (Q1 - Q2) / 100, determine that the green light duration in the second signal timing plan for the intersection is g i1 = g0 - min(int(Q i - Q1) / 100, 3); where min(int(Q i - Q1) / 100, 3) is the signal timing adjustment amount; when g i1 < g min , calculate Δg = g min - g i1 ; let g i1 = g min , determine that the cycle duration in the second signal timing plan for the intersection is C i = C + Δg; where Q i is the first traffic flow, Q1 is the lower boundary value of the traffic flow in the traffic flow range corresponding to the severe congestion level, Q2 is the lower boundary value of the traffic flow in the traffic flow range corresponding to the general congestion level, g i1 is the green light duration in the second signal timing plan, g0 is the green light duration in the current first signal timing plan, g min is the minimum green light duration configured for the intersection, C is the cycle duration in the current first signal timing plan, and C i is the cycle duration in the second signal timing plan.

9. The method according to claim 1, wherein Determining the fifth signal timing plan of the intersection according to the first ratio of the second traffic volume difference to the third traffic volume difference and the difference includes: If the first congestion level is the general congestion level, according to the formula calculate the green signal ratio λ i , when λ i ≤ g1 / C1, take λ i = g1 / C1; when the signal light cycle duration remains unchanged, then: When it is calculated that gi2 < gmin, then take gi2 = gmin; where g2 is the green light duration in the third signal light timing plan corresponding to the pre-determined general congestion level, c2 is the cycle duration in the third signal light timing plan corresponding to the pre-determined general congestion level, g1 is the signal light cycle duration in the fourth signal light timing plan corresponding to the pre-determined severe congestion level, c1 is the cycle duration in the fourth signal light timing plan corresponding to the pre-determined severe congestion level, and gi2 is the green light duration in the fifth signal light timing plan; If the first congestion level is the slow traffic congestion level, according to the formula calculate the green signal ratio λ i , when λ i ≤g2 / C2, take λ i = g2 / C2; without changing the signal light cycle duration, then: When it is calculated that gi2 < gmin, then take gi2 = gmin; where g3 is the green light duration in the third signal light timing plan corresponding to the pre-determined slow traffic congestion level, c3 is the cycle duration in the third signal light timing plan corresponding to the pre-determined slow traffic congestion level, g2 is the green light duration in the fourth signal light timing plan corresponding to the pre-determined general congestion level, c2 is the cycle duration in the fourth signal light timing plan corresponding to the pre-determined general congestion level, and gi2 is the green light duration in the fifth signal light timing plan.

10. The method according to claim 1, characterized in that, The process of determining each intersection upstream of the target area includes: For each candidate intersection within a preset range area upstream of the target area, determine the sixth traffic volume flowing into the intersection from the upstream road section associated with the candidate intersection within a preset second time period, and the sixth ratio of the seventh traffic volume flowing into the target area among the sixth traffic volume. If the sixth ratio is less than a preset ratio threshold, filter out the candidate intersection; otherwise, determine the candidate intersection as an intersection upstream of the target area.

Images