Intersection traffic flow state identification method and traffic signal control device

Abstract

The application provides a kind of intersection traffic flow state identification method and traffic signal control equipment, it is related to intelligent transportation technical field.The application is according to each kind of traffic flow turning at target intersection, according to the maximum saturation flow rate of this kind of traffic flow turning and the actual signal control traffic data of this kind of traffic flow turning in current signal control period, the actual saturation of this kind of traffic flow turning in current signal control period is calculated, and the historical traffic flow state score of the last signal control period of this kind of traffic flow turning in current signal control period is combined, according to the target traffic flow state score rule adapted to the target intersection, the actual traffic flow state score of this kind of traffic flow turning in current signal control period is calculated to identify traffic flow state, so as to deeply consider the influence of traffic flow fluctuation in intersection traffic flow state identification process, ensure that the final traffic flow state identification result can accurately reflect the overall change trend of real intersection traffic flow state in time dimension level.

Description

Technical Field

[0001] This application relates to the field of intelligent transportation technology, and more specifically, to a method for recognizing traffic flow status at intersections and a traffic signal control device. Background Technology

[0002] With the continuous improvement of people's living standards and the rapid development of cities, urban transportation systems are facing increasingly severe challenges as cities modernize. The increasing number of vehicles, worsening traffic congestion, frequent traffic accidents, and waste of social resources seriously affect people's travel efficiency, quality of life, and physical and mental health. Therefore, alleviating traffic congestion in cities has significant economic and ecological implications.

[0003] Currently, existing traffic signal control mechanisms at intersections primarily rely on dynamically adjusting signal timing schemes based on real-time changes in traffic flow to alleviate congestion. However, it's worth noting that due to variations in vehicle performance, driver habits, and other factors, the traffic conditions at intersection lanes fluctuate significantly between different signal control cycles. (For example, a lane might be identified as flowing smoothly in one signal control cycle, but if a driver near the intersection stops and becomes distracted during the red light phase in the next cycle and fails to immediately leave the intersection when the green light turns on, the number of vehicles leaving the intersection in that cycle may decrease, causing the lane to be identified as congested.) This makes it difficult to effectively reflect the overall trend of real-time traffic flow at intersections. Consequently, signal timing schemes determined directly from real-time lane traffic conditions may not only fail to improve traffic efficiency but may also cause additional delays for waiting vehicles at the intersection. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a method for identifying traffic flow status at intersections and a traffic signal control device that can deeply consider the impact of traffic flow fluctuations on the process of identifying traffic flow status at intersections, and ensure that the traffic flow status identification results for different traffic flow turning at any intersection can effectively reflect the overall changing trend of the real traffic flow status at the intersection in the time dimension, improve the accuracy of traffic flow status identification at intersections, and provide a highly accurate decision-making basis for adjusting signal timing schemes based on traffic flow status at intersections.

[0005] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows:

[0006] Firstly, this application provides a method for identifying traffic flow status at an intersection, the method comprising:

[0007] Obtain the maximum saturation flow rate of various traffic flow turns at the target intersection, as well as the actual traffic signal control data of the various traffic flow turns in the current signal control cycle;

[0008] For each type of traffic flow turn at the target intersection, the actual saturation of that type of traffic flow turn in the current signal control cycle is calculated based on the maximum saturation rate of that type of traffic flow turn and the actual signal control traffic data.

[0009] Based on the target traffic flow state scoring rules adapted to the target intersection, and based on the actual saturation of the traffic flow turning and the historical traffic flow state score of the traffic flow turning in the previous signal control cycle in the current signal control cycle, the actual traffic flow state score of the traffic flow turning in the current signal control cycle is calculated.

[0010] Traffic flow status is identified by the actual traffic flow status score of this type of traffic flow turning according to the target traffic flow status scoring rule, so as to obtain the overall traffic flow status of this type of traffic flow turning in the current signal control cycle.

[0011] In an optional implementation, the step of obtaining the maximum saturation flow rate for various traffic flow turns at the target intersection includes:

[0012] For each type of traffic flow turning at the target intersection, the saturation flow rate is calculated based on the lane flow data and green light duration for that type of traffic flow turning in multiple historical signal control cycles, and the historical saturation flow rate corresponding to that type of traffic flow turning in multiple historical signal control cycles is obtained.

[0013] The historical saturation flow rate corresponding to this type of traffic flow turning in multiple historical signal control periods was statistically analyzed, and the 90th percentile saturation flow rate in the corresponding statistical results was taken as the maximum saturation flow rate of this type of traffic flow turning.

[0014] In an optional implementation, the saturation flow rate of the i-th traffic flow turning at the target intersection in the k-th signal control cycle is calculated using the following formula:

[0015]

[0016] in, This is used to represent the saturation flow rate of the i-th type of traffic flow turning in the k-th signal control cycle. N is used to represent the green light duration of the i-th type of traffic flow turning in the k-th signal control cycle. i This is used to represent the total number of lanes at the target intersection for the i-th type of traffic flow turning. This is used to represent the traffic flow value of the j-th lane in the lane flow data of the k-th signal control period for the i-th type of traffic flow turning.

[0017] In an optional implementation, the actual traffic data for each traffic flow turn includes the current signal control cycle duration, the actual green light duration, and the actual traffic flow value for each lane. The traffic saturation of the i-th traffic flow turn at the target intersection during the current signal control cycle is calculated using the following formula:

[0018]

[0019] Where, p i S is used to represent the traffic saturation of the i-th type of traffic flow turning in the current signal control cycle. i g is used to represent the maximum saturation flow rate for the i-th type of traffic flow turning. i C is used to represent the actual green light duration of the i-th type of traffic flow turning in the current signal control cycle. i N is used to represent the current signal control cycle duration of the i-th type of traffic flow turning. i q represents the total number of lanes at the target intersection for the i-th type of traffic flow turning. i,j λ is used to represent the actual traffic flow value of the j-th lane in the current signal control cycle for the i-th type of traffic flow turning. i This is used to represent the green ratio of the i-th type of traffic flow turning in the current traffic control cycle.

[0020] In an optional implementation, the target traffic flow state scoring rule records a first cycle of consecutive numbers. The step of calculating the actual traffic flow state score for the type of traffic flow turning in the current signal control cycle, based on the target traffic flow state scoring rule adapted to the target intersection and considering the actual saturation of the type of traffic flow turning and the historical traffic flow state score of the type of traffic flow turning in the previous signal control cycle, includes:

[0021] For this type of traffic flow turning, the target saturation range corresponding to the actual saturation is determined in the saturation range of slow traffic, smooth traffic, and congested traffic.

[0022] Based on the target saturation range, it is detected whether the actual saturation ranges of each of the target period consecutively for the current signal control period are consistent, and whether the lane traffic state represented by the target saturation range is consistent with the historical traffic flow state represented by the historical traffic flow state score, wherein the number of consecutive target periods is obtained by adding one to the number of consecutive first periods;

[0023] If the true saturation ranges of the target cycle are consistent for a consecutive number of consecutive signal control cycles, and the lane traffic state represented by the target saturation range is consistent with the historical traffic flow state represented by the historical traffic flow state score, then the historical traffic flow state score is directly used as the actual traffic flow state score of this type of traffic flow turning in the current signal control cycle. Otherwise, a target state score matching the target saturation range is calculated based on the historical traffic flow state score, and the calculated target state score is used as the actual traffic flow state score of this type of traffic flow turning in the current signal control cycle.

[0024] In an optional implementation, the target traffic flow state scoring rule records a first accumulated score value directly corresponding to the traffic slow-moving state saturation interval, a second accumulated score value corresponding to the traffic congestion state saturation interval, a first score decay value corresponding to the traffic free-flowing state saturation interval, and a second score decay value corresponding to the traffic slow-moving state saturation interval and the congested traffic flow state. Then, the step of calculating the target state score matching the target saturation interval based on the historical traffic flow state scores includes:

[0025] If the target saturation range falls within the traffic congestion state saturation range, the historical traffic flow state score and the second accumulated score are added together to obtain the target state score.

[0026] If the target saturation range falls within the traffic flow saturation range, the historical traffic flow state score and the first score decay value are subtracted to obtain the target state score.

[0027] If the target saturation range falls within the traffic slow-moving state saturation range, it is detected whether the historical traffic flow state represented by the historical traffic flow state score belongs to the congested traffic flow state.

[0028] If the historical traffic flow status is detected to be a congested traffic flow status, the historical traffic flow status score and the second score attenuation value are subtracted to obtain the target status score; otherwise, the historical traffic flow status score and the first score accumulation value are added to obtain the target status score.

[0029] In an optional implementation, the target traffic flow state scoring rule records a slow traffic flow state score threshold and a congested traffic flow state score threshold. The step of identifying the traffic flow state based on the actual traffic flow state score of this type of traffic flow turning according to the target traffic flow state scoring rule, and obtaining the overall traffic flow state of this type of traffic flow turning in the current signal control cycle, includes:

[0030] Detect whether the actual traffic flow state score of this type of traffic flow turning is greater than or equal to the congested traffic flow state score threshold;

[0031] If the actual traffic flow status score of the traffic flow turning is detected to be greater than or equal to the congested traffic flow status score threshold, then it is determined that the overall traffic flow status of the traffic flow turning in the current signal control cycle belongs to the congested traffic flow status; otherwise, it is detected whether the actual traffic flow status score of the traffic flow turning is greater than or equal to the slow traffic flow status score threshold.

[0032] If the actual traffic flow state score of the detected traffic flow turning is greater than or equal to the slow traffic flow state score threshold, it is determined that the overall traffic flow state of the traffic flow turning in the current signal control cycle belongs to the slow traffic flow state.

[0033] If the actual traffic flow state score of the detected traffic flow turning is less than the slow traffic flow state score threshold, it is determined that the overall traffic flow state of the traffic flow turning in the current signal control cycle belongs to the smooth traffic flow state.

[0034] In an optional implementation, the method further includes:

[0035] Traffic flow state scoring rules are constructed based on multiple preset score distribution constraints to obtain multiple candidate traffic flow state scoring rules.

[0036] Based on at least one week of historical traffic flow data at the target intersection, a signal timing scheme library for the target intersection is constructed. The signal timing scheme library includes signal timing schemes for the target intersection under different combinations of traffic flow turning states. Each combination of traffic flow turning states consists of any one of the traffic flow states of slow traffic flow, congested traffic flow, and unobstructed traffic flow at the target intersection.

[0037] The multiple candidate traffic flow state scoring rules are used as the traffic flow state evaluation criteria for the target intersection, and the signal timing scheme library is called to perform signal control simulation on the target intersection based on the traffic flow state evaluation criteria, so as to determine the rule fit degree of each of the multiple candidate traffic flow state scoring rules at the target intersection.

[0038] The candidate traffic flow state scoring rule with the highest matching degree is selected as the target traffic flow state scoring rule that matches the target intersection.

[0039] In an optional implementation, the step of constructing a signal timing scheme library for the target intersection based on at least one week of historical traffic flow data at the target intersection includes:

[0040] For each type of traffic flow turn at the target intersection, the 75th percentile flow value of the off-peak flow data corresponding to that type of traffic flow turn is extracted from the historical traffic flow data as the overall flow value for the smooth flow state of that type of traffic flow turn, and the 50th percentile flow value of the peak flow data corresponding to that type of traffic flow turn is extracted from the historical traffic flow data as the overall flow value for the congested flow state of that type of traffic flow turn.

[0041] Extract the 50th percentile flow value of the effective flow data in the historical traffic flow data that corresponds to this type of traffic flow turning and is in a smooth state and a congested state, and use it as the overall flow value of the slow state for this type of traffic flow turning.

[0042] Divide the overall traffic flow value of the smooth traffic flow, slow traffic flow, and congested traffic flow of this type of traffic flow turn by the total number of lanes at the target intersection to obtain the reference traffic flow value corresponding to the smooth traffic flow, slow traffic flow, and congested traffic flow states, respectively.

[0043] For each combination of traffic flow turning states, based on the reference flow values ​​of each traffic flow turning state under different traffic flow states, the phase flow values ​​of various traffic phases at the target intersection under that combination of traffic flow turning states are calculated.

[0044] Based on the phase flow values ​​of various traffic phases at the target intersection under this combination of traffic flow turning states, the signal control cycle duration and green light duration are calculated to obtain the signal timing scheme of the target intersection under this combination of traffic flow turning states.

[0045] Secondly, this application provides a traffic signal control device, the control device including a processor and a memory, the memory storing a computer program executable by the processor, the processor executing the computer program to implement the intersection traffic flow state recognition method described in any of the foregoing embodiments.

[0046] In this case, the beneficial effects of the embodiments of this application may include the following:

[0047] This application, for each type of traffic flow turning at a target intersection, calculates the actual saturation of that traffic flow turning in the current signal control cycle based on its maximum saturation rate and actual signal traffic data. It then combines this with the historical traffic flow state score from the previous signal control cycle and, according to the target traffic flow state scoring rules adapted to the target intersection, calculates the actual traffic flow state score for that traffic flow turning in the current signal control cycle. This process identifies the overall traffic flow state of that traffic flow turning in the current signal control cycle, thus deeply considering the impact of traffic flow volatility on intersection traffic flow state identification. This ensures that the final traffic flow state identification results for different traffic flow turnings at any intersection effectively reflect the overall changing trend of the real intersection traffic flow state over time, improving the accuracy of intersection traffic flow state identification and providing a highly accurate decision-making basis for adjusting signal timing schemes based on intersection traffic flow state.

[0048] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0049] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a schematic diagram of the equipment composition of the traffic signal control device provided in the embodiments of this application;

[0051] Figure 2 One of the flowcharts for the intersection traffic flow state recognition method provided in the embodiments of this application;

[0052] Figure 3 for Figure 2 A flowchart illustrating the sub-steps included in step S210;

[0053] Figure 4 for Figure 2 A flowchart illustrating the sub-steps included in step S230;

[0054] Figure 5 for Figure 2 A flowchart illustrating the sub-steps included in step S240;

[0055] Figure 6A second schematic flowchart of the intersection traffic flow state recognition method provided in the embodiments of this application;

[0056] Figure 7 for Figure 6 The flowchart of the sub-steps included in step S260 is shown below.

[0057] Icons: 100 - Traffic signal control equipment; 110 - Memory; 120 - Processor; 130 - Communication unit. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0059] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0060] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0061] In the description of this application, it should be understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are used only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the equipment or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0062] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0063] Furthermore, it is understood in the description of this application that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0064] Through diligent research, the applicant discovered that existing intersection traffic flow status recognition schemes primarily rely on thresholds determined by human experience for status identification, or on labeling traffic flow states based on thresholds determined by human experience and then using artificial intelligence methods for deep learning to utilize neural network models for status identification. However, it is worth noting that both of these approaches essentially still rely on learning from human experience for status identification, meaning the accuracy of status judgment is highly dependent on the individual experience of engineers, thus affecting the implementation effectiveness of intersection signal control schemes. In other words, existing intersection traffic flow status recognition schemes often suffer from low accuracy, making it difficult to provide a reliable basis for decision-making in adjusting signal timing schemes based on intersection traffic flow status.

[0065] In this context, to address the aforementioned issues, this application provides a method for identifying traffic flow status at intersections and a traffic signal control device. This method deeply considers the impact of traffic flow volatility on the process of identifying traffic flow status at intersections, ensuring that the traffic flow status identification results for different traffic flow directions at any intersection can effectively reflect the overall trend of the actual traffic flow status at the intersection in the time dimension. This improves the accuracy of traffic flow status identification at intersections and provides a more accurate decision-making basis for adjusting signal timing schemes based on traffic flow status at intersections.

[0066] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0067] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the equipment composition of the traffic signal control device 100 provided in this application embodiment. In this application embodiment, the traffic signal control device 100 can be communicatively connected to traffic monitoring equipment and traffic lights deployed at any traffic intersection (e.g., a four-lane signalized intersection), so as to use the traffic monitoring equipment to monitor the real traffic conditions of the corresponding traffic intersection in different road entrance directions (e.g., the north entrance direction, south entrance direction, east entrance direction, and west entrance direction of a four-lane signalized intersection), and use the traffic lights to provide signal indication of the lane release status of the traffic intersection in different road entrance directions.

[0068] In this embodiment, the traffic signal control device 100, based on the real-time traffic condition data collected by the traffic monitoring device, deeply considers the impact of traffic flow fluctuations on the traffic flow state identification process at the intersection, ensuring that different traffic flow directions at the corresponding traffic intersection (for example, a four-lane signalized intersection with one left-turn lane, two straight lanes, and one right-turn lane at each of the four entrance directions can include "North entrance left-turn flow", "North entrance straight flow", "North entrance right-turn flow", "South entrance left-turn flow", "South entrance straight flow", "South entrance right-turn flow", "East entrance left-turn flow", "East entrance straight flow", "East entrance right-turn flow", "West entrance left-turn flow", "West entrance straight flow", and "West entrance right-turn flow") The traffic flow status recognition results can effectively reflect the overall changing trend of the real intersection traffic flow status in the time dimension, improve the accuracy of intersection traffic flow status recognition, and select a specific signal timing scheme that matches the intersection traffic flow status recognition results (composed of the traffic flow status recognition results of all traffic flows turning at the intersection) from the signal timing scheme library of the intersection (which includes signal timing schemes for the corresponding intersection under different combinations of traffic flow turning traffic flow statuses, where each combination of traffic flow turning traffic flow statuses is composed of any one of the traffic flow statuses of slow traffic flow, congested traffic flow, and free traffic flow at the intersection). This will control the working state of the traffic lights, so that the intersection can achieve the desired traffic control effect of improving the traffic operation efficiency and maximizing the traffic operation potential of the intersection.

[0069] In this embodiment, the traffic signal control device 100 may include a memory 110, a processor 120, and a communication unit 130. The memory 110, processor 120, and communication unit 130 are electrically connected directly or indirectly to each other to achieve data transmission or interaction. For example, these components may be electrically connected via one or more communication buses or signal lines.

[0070] In this embodiment, the memory 110 may be, but is not limited to, random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc. The memory 110 is used to store computer programs, and the processor 120 can execute the computer programs accordingly after receiving execution instructions.

[0071] Furthermore, in this embodiment, the memory 110 can also be used to store the effective traffic flow state scoring rules adapted to different traffic intersections. The effective traffic flow state scoring rules are used to evaluate the traffic flow state score of each traffic flow turning at the corresponding traffic intersection in any signal control cycle, considering the volatility of traffic flow from a time dimension perspective. The evaluated traffic flow state score is used to characterize the overall change trend of the real traffic flow state (i.e., slow traffic flow state, congested traffic flow state, or smooth traffic flow state) in the time dimension. The effective traffic flow state scoring rules adapted to different traffic intersections all satisfy multiple preset score distribution constraints. Each preset score distribution constraint is used to describe the numerical distribution constraint relationship between the traffic flow state score of any signal control cycle, different traffic flow state score thresholds (including slow traffic flow state score threshold and congested traffic flow state score threshold), and the saturation distribution of multiple consecutive signal control cycles including that signal control cycle.

[0072] In this embodiment, the processor 120 can be an integrated circuit chip with signal processing capabilities. The processor 120 can be a general-purpose processor, including at least one of a Central Processing Unit (CPU), Graphics Processing Unit (GPU), Network Processor (NP), Digital Signal Processor (DSP), Application-Specific Integrated Circuit (ASIC), Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor can be a microprocessor or any conventional processor, capable of implementing or executing the methods, steps, and logic block diagrams disclosed in this embodiment.

[0073] In this embodiment of the application, the communication unit 130 is used to establish a communication connection between the traffic signal control device 100 and other electronic devices through a network, and to send and receive data through the network, wherein the network includes a wired communication network and a wireless communication network.

[0074] In this embodiment, the traffic signal control device 100 may pre-store a specific computer program related to the intersection traffic flow state recognition function in the memory 110, and by driving the processor 120 to execute the specific computer program stored in the memory 110, the influence of traffic flow fluctuations on the intersection traffic flow state recognition process is deeply considered, ensuring that the traffic flow state recognition results for different traffic flow directions at any intersection can effectively reflect the overall change trend of the real intersection traffic flow state in the time dimension, improving the accuracy of intersection traffic flow state recognition, and facilitating the provision of a highly accurate decision basis for adjusting the signal timing scheme based on the intersection traffic flow state.

[0075] Understandable Figure 1 The block diagram shown is only a schematic diagram of one composition of the traffic signal control device 100. The traffic signal control device 100 may also include... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown. Figure 1 The components shown can be implemented using hardware, software, or a combination thereof.

[0076] In this application, to ensure that the traffic signal control device 100 can deeply consider the impact of traffic flow fluctuations on the intersection traffic flow state recognition process, and so that the final traffic flow state recognition result can effectively reflect the overall change trend of the real intersection traffic flow state in the time dimension, this application embodiment achieves the aforementioned objective by providing an intersection traffic flow state recognition method. The intersection traffic flow state recognition method provided in this application will be described in detail below.

[0077] Please refer to Figure 2 , Figure 2 This is one of the flowcharts illustrating the intersection traffic flow state identification method provided in this application embodiment. In this application embodiment, the intersection traffic flow state identification method may include steps S210 to S240.

[0078] Step S210: Obtain the maximum saturation flow rate of various traffic flow turning at the target intersection, as well as the actual traffic signal control data of various traffic flow turning in the current signal control cycle.

[0079] In this embodiment, the target intersection is any traffic intersection monitored in real time by the traffic signal control device 100 through the traffic monitoring device; the maximum saturation flow rate of various traffic flow turns at the target intersection is used to describe the maximum value of the saturation flow rate that the corresponding traffic flow turn generally maintains in the historical traffic records before the current signal control cycle; the actual signal control traffic data of various traffic flow turns at the target intersection in the current signal control cycle includes the duration of the current signal control cycle of the corresponding traffic flow turn, the actual green light duration of the corresponding traffic flow turn in the current signal control cycle, and the actual flow rate of each lane involved in the corresponding traffic flow turn at the target intersection in the current signal control cycle.

[0080] Alternatively, please refer to Figure 3 , Figure 3 yes Figure 2 The flowchart of step S210 includes the sub-steps. In the embodiments of this application, the step "obtaining the maximum saturation flow rate of various traffic flow turns at the target intersection" in step S210 may include sub-steps S211 to S212 to effectively extract the maximum saturation flow rate of different traffic flow turns from the historical traffic records of the target intersection.

[0081] Sub-step S211: For each type of traffic flow turning at the target intersection, calculate the saturation flow rate based on the lane flow data and green light duration for each type of traffic flow turning in multiple historical signal control cycles, and obtain the historical saturation flow rate corresponding to each type of traffic flow turning in multiple historical signal control cycles.

[0082] In this embodiment, the plurality of historical traffic control cycles can be all historical traffic control cycles of the same day last week of the current traffic control cycle, or they can be historical traffic control cycles that are directly adjacent to and continuous with the current traffic control cycle; the lane flow data for any traffic flow turning in a certain traffic control cycle includes the traffic flow values ​​of all lanes involved in that traffic flow turning at the target intersection within that traffic control cycle.

[0083] In this process, the saturation flow rate of the i-th traffic flow turning at the target intersection in the k-th signal control cycle is calculated using the following formula:

[0084]

[0085] in, This is used to represent the saturation flow rate of the i-th type of traffic flow turning in the k-th signal control cycle. N is used to represent the green light duration of the i-th type of traffic flow turning in the k-th signal control cycle. i This is used to represent the total number of lanes at the target intersection for the i-th type of traffic flow turning. This is used to represent the traffic flow value of the j-th lane in the lane flow data of the k-th signal control period for the i-th type of traffic flow turning.

[0086] Sub-step S212 involves statistically analyzing the historical saturation flow rate corresponding to this type of traffic flow turning in multiple historical signal control periods, and taking the 90th percentile saturation flow rate in the corresponding statistical results as the maximum saturation flow rate for this type of traffic flow turning.

[0087] Therefore, this application can effectively extract the maximum saturation flow rate of different traffic flow turning points from the historical traffic records of the target intersection by executing the above sub-steps S211 to S212.

[0088] Step S220: For each type of traffic flow turning at the target intersection, calculate the actual saturation of that type of traffic flow turning in the current signal control cycle based on the maximum saturation rate of that type of traffic flow turning and the actual signal control traffic data.

[0089] In this embodiment, after acquiring the maximum saturation flow rate of any traffic flow turning at the target intersection, and the actual traffic control data for that traffic flow turning in the current signal control cycle, the traffic signal control device 100 calculates the actual saturation of that traffic flow turning in the current signal control cycle according to the traffic saturation calculation formula. The traffic saturation of the i-th traffic flow turning at the target intersection in the current signal control cycle is calculated using the following formula:

[0090]

[0091] Where, p iS is used to represent the traffic saturation of the i-th type of traffic flow turning in the current signal control cycle. i g is used to represent the maximum saturation flow rate for the i-th type of traffic flow turning. i C is used to represent the actual green light duration of the i-th type of traffic flow turning in the current signal control cycle. i N is used to represent the current signal control cycle duration of the i-th type of traffic flow turning. i q represents the total number of lanes at the target intersection for the i-th type of traffic flow turning. i,j λ is used to represent the actual traffic flow value of the j-th lane in the current signal control cycle for the i-th type of traffic flow turning. i This is used to represent the green ratio of the i-th type of traffic flow turning in the current traffic control cycle.

[0092] Step S230: Based on the target traffic flow state scoring rules adapted to the target intersection, and based on the actual saturation of the traffic flow turning and the historical traffic flow state score of the traffic flow turning in the previous signal control cycle of the current signal control cycle, calculate the actual traffic flow state score of the traffic flow turning in the current signal control cycle.

[0093] In this embodiment, the traffic signal control device 100 can extract the target traffic flow state scoring rule adapted to the target intersection from the pre-stored effective traffic flow state scoring rules adapted to different traffic intersections. Then, for each type of traffic flow turning at the target intersection, the target traffic flow state scoring rule is invoked to evaluate the traffic flow state score based on the actual saturation of the type of traffic flow turning in the current signal control cycle, the historical traffic flow state score of the type of traffic flow turning in the previous signal control cycle of the current signal control cycle, and the actual saturation of the type of traffic flow turning in multiple historical signal control cycles adjacent and consecutive to the current signal control cycle. This is to consider the impact of traffic flow volatility on the overall trend of traffic flow changes from a time dimension perspective, and to ensure that the actual traffic flow state score evaluated for the type of traffic flow turning can effectively reflect the real traffic flow situation.

[0094] In this process, the target traffic flow state scoring rule must satisfy at least one of the preset score distribution constraints: "If the lane traffic state (traffic state directly identified by saturation) remains consistent for each of the m+1 consecutive signal control cycles, then the actual traffic flow state score of the last signal control cycle is consistent with the actual traffic flow state score of the second-to-last signal control cycle (i.e., the signal control cycle preceding the last signal control cycle), wherein the historical traffic flow state of the second-to-last signal control cycle is consistent with the lane traffic state." In this case, the target traffic flow state scoring rule will record the first consecutive number of cycles (represented by m). At this point, the sub-steps included in step S230 can be as follows: Figure 4As shown. Step S230 may include sub-steps S231 to S234 to consider the impact of traffic flow volatility on the overall trend of traffic flow changes from a time perspective, ensuring that the actual traffic flow state score evaluated for any traffic flow turning can effectively reflect the real traffic flow situation at the target intersection.

[0095] Sub-step S231: For this type of traffic flow turning, determine the target saturation range where the actual saturation is located in the saturation range of slow traffic, smooth traffic, and congested traffic.

[0096] In this embodiment, the target traffic flow state scoring rule records the specific interval contents of each of the following: the saturation interval for slow traffic (i.e., the range of saturation values ​​that must be satisfied when any traffic flow turns and the traffic state of the corresponding lane is determined to be slow traffic), the saturation interval for smooth traffic (i.e., the range of saturation values ​​that must be satisfied when any traffic flow turns and the traffic state of the corresponding lane is determined to be smooth traffic), and the saturation interval for congested traffic (i.e., the range of saturation values ​​that must be satisfied when any traffic flow turns and the traffic state of the corresponding lane is determined to be congested). (For example, the saturation intervals for smooth traffic, slow traffic, and congested traffic are expressed as (0,0.8), [0.8,0.9), and [0.9,1], respectively).

[0097] Therefore, for any type of traffic flow turning, the traffic signal control device 100 can determine the target saturation range where the actual saturation is located by matching the actual saturation of the type of traffic flow turning in the current signal control cycle with the saturation range of the slow traffic state, the saturation range of the smooth traffic state, and the saturation range of the congested traffic state, respectively. At this time, the target saturation range is the true saturation range of the type of traffic flow turning in the current signal control cycle, and the lane traffic state (i.e., smooth traffic state, slow traffic state, or congested traffic state) represented by the target saturation range is the actual lane traffic state of the type of traffic flow turning in the current signal control cycle.

[0098] Sub-step S232: Based on the target saturation interval, detect whether the true saturation intervals of each of the target cycle consecutively for the current signal control cycle are consistent, and whether the lane traffic state represented by the target saturation interval is consistent with the historical traffic flow state represented by the historical traffic flow state score.

[0099] In this embodiment, the number of consecutive target cycles is obtained by adding one to the number of consecutive first cycles, that is, the number of consecutive target cycles is represented by m+1; if there are consecutive signal control cycles of the target cycle (based on whether the true saturation range of each of the current signal control cycle and the m historical signal control cycles that are adjacent and consecutive to the current signal control cycle is consistent, it indicates that the lane traffic state of each of these m+1 signal control cycles is consistent.

[0100] The target traffic flow state scoring rule also records a slow traffic flow state score threshold (which can be represented by e) and a congested traffic flow state score threshold (which can be represented by f). If the traffic flow state score for a certain type of traffic flow turning is less than the slow traffic flow state score threshold, then the traffic flow state score will correspond to a smooth traffic flow state. If the traffic flow state score for that type of traffic flow turning is greater than or equal to the slow traffic flow state score threshold but less than the congested traffic flow state score threshold, then the traffic flow state score will correspond to a slow traffic flow state. Furthermore, if the traffic flow state score for that type of traffic flow turning is greater than or equal to the congested traffic flow state score threshold, then the traffic flow state score will correspond to a congested traffic flow state. Therefore, the traffic signal control device 100 can identify the historical traffic flow state represented by the historical traffic flow state score of the previous signal control cycle for any traffic flow direction based on the slow traffic flow state score threshold and the congested traffic flow state score threshold. Then, it performs state matching between the lane traffic state of the traffic flow direction in the current signal control cycle and the historical traffic flow state represented by the historical traffic flow state score to determine whether the lane traffic state and the historical traffic flow state are consistent. Specifically, if the lane traffic state is a smooth traffic state and the corresponding historical traffic flow state is a smooth traffic flow state, then the lane traffic state and the historical traffic flow state are consistent; if the lane traffic state is a slow traffic state and the corresponding historical traffic flow state is a slow traffic flow state, then the lane traffic state and the historical traffic flow state are consistent; if the lane traffic state is a congested traffic state and the corresponding historical traffic flow state is a congested traffic flow state, then the lane traffic state and the historical traffic flow state are consistent.

[0101] In this case, if the actual saturation range of each of the target period's consecutive signal control periods is consistent, and the lane traffic state represented by the target saturation range is consistent with the historical traffic flow state represented by the historical traffic flow state score, then it indicates that the corresponding traffic flow turning in the current signal control period substantially meets the constraint condition "If the lane traffic state (traffic state directly identified by saturation) of each of the consecutive m+1 signal control periods is consistent, then the actual traffic flow state score of the last signal control period is consistent with the actual traffic flow state score of the second-to-last signal control period (i.e., the signal control period preceding the last signal control period), wherein the historical traffic flow state of the second-to-last signal control period is consistent with the lane traffic state", then the traffic signal control device 100 will execute sub-step S233 accordingly; otherwise, the traffic signal control device 100 will execute sub-step S234 accordingly.

[0102] Sub-step S233 directly uses the historical traffic flow state score as the actual traffic flow state score for that type of traffic flow turning in the current signal control cycle.

[0103] Sub-step S234: Calculate the target state score that matches the target saturation range based on the historical traffic flow state score, and use the calculated target state score as the actual traffic flow state score of this type of traffic flow turning in the current signal control cycle.

[0104] In this embodiment, when it is determined that a certain traffic flow turning does not meet the constraint condition "if the lane traffic state remains consistent for each of the m+1 consecutive signal control cycles, then the actual traffic flow state score of the last signal control cycle is consistent with the actual traffic flow state score of the second-to-last signal control cycle, wherein the historical traffic flow state of the second-to-last signal control cycle is consistent with the lane traffic state", the traffic signal control device 100 will add the first score accumulation value directly corresponding to the traffic slow-moving state saturation interval (i.e., the positive score that needs to be added to the historical traffic flow state score of the previous signal control cycle when the lane traffic state of the corresponding traffic flow turning is determined to be a slow-moving state in a certain signal control cycle, which can be represented by 'a') and the second score accumulation value corresponding to the traffic congestion state saturation interval (i.e., the positive score that needs to be added to the historical traffic flow state score of the previous signal control cycle when the lane traffic state of the corresponding traffic flow turning is determined to be a traffic congestion state in a certain signal control cycle) recorded based on the target traffic flow state scoring rule. The system comprises: a positive score superimposed on the historical traffic flow status score (represented by b); a first score attenuation value corresponding to the traffic flow saturation interval (i.e., a positive score to be subtracted from the historical traffic flow status score of the previous signal control period when the lane traffic status of the corresponding traffic flow turning is determined to be a traffic flow state in a certain signal control period, represented by c); and a second score attenuation value corresponding to the traffic slow-moving saturation interval and the congested traffic flow state (i.e., a positive score to be subtracted from the historical traffic flow status score of the previous signal control period when the lane traffic status of the corresponding traffic flow turning is determined to be a traffic slow-moving state in a certain signal control period and the historical traffic flow status of the previous signal control period is a congested traffic flow state, represented by d). Combining the target saturation interval of the corresponding traffic flow turning in the current signal control period and the historical traffic flow status score of the previous signal control period, the system calculates the target status score of the traffic flow turning in the current signal control period that matches the target saturation interval as the true actual traffic flow status score.

[0105] In this process, the step "calculate the target state score matching the target saturation interval based on the historical traffic flow state score" in sub-step S234 may include:

[0106] If the target saturation range falls within the traffic congestion state saturation range, the historical traffic flow state score and the second accumulated score are added together to obtain the target state score.

[0107] If the target saturation range falls within the traffic flow saturation range, the historical traffic flow state score and the first score decay value are subtracted to obtain the target state score.

[0108] If the target saturation range falls within the traffic slow-moving state saturation range, it is detected whether the historical traffic flow state represented by the historical traffic flow state score belongs to the congested traffic flow state.

[0109] If the historical traffic flow status is detected to be a congested traffic flow status, the historical traffic flow status score and the second score attenuation value are subtracted to obtain the target status score; otherwise, the historical traffic flow status score and the first score accumulation value are added to obtain the target status score.

[0110] Therefore, by executing the above sub-steps S231 to S234, this application can consider the impact of traffic flow volatility on the overall trend of traffic flow changes from a time dimension perspective, ensuring that the actual traffic flow state score evaluated for any type of traffic flow turning can effectively reflect the real traffic flow situation at the target intersection.

[0111] Step S240: According to the target traffic flow state scoring rules, the actual traffic flow state score of this type of traffic flow turning is used to identify the traffic flow state, so as to obtain the overall traffic flow state of this type of traffic flow turning in the current signal control cycle.

[0112] In this embodiment, the target traffic flow state scoring rule records a slow traffic flow state score threshold and a congested traffic flow state score threshold, wherein the congested traffic flow state score threshold is greater than the slow traffic flow state score threshold. After determining the actual traffic flow state score of any traffic flow turning at the target intersection in the current signal control cycle, the traffic signal control device 100 can accurately identify the overall traffic flow state of the corresponding traffic flow turning in the current signal control cycle by comparing the actual traffic flow state score with the slow traffic flow state score threshold and the congested traffic flow state score threshold. At this time, the sub-steps included in step S240 can be as follows: Figure 5 As shown. Step S240 may include sub-steps S241 to S245 to accurately identify the overall traffic flow status of any traffic flow turning direction in the current signal control cycle.

[0113] Sub-step S241: Detect whether the actual traffic flow state score of this type of traffic flow turning is greater than or equal to the congested traffic flow state score threshold.

[0114] In this embodiment, if the actual traffic flow state score of a certain traffic flow turn in the current signal control cycle is greater than or equal to the congested traffic flow state score threshold, the traffic signal control device 100 will execute sub-step S242 for that type of traffic flow turn; otherwise, the traffic signal control device 100 will execute sub-step S243 for that type of traffic flow turn.

[0115] Sub-step S242 determines that the traffic flow turning of this type belongs to the congested traffic flow state in the current signal control cycle.

[0116] Sub-step S243: Detect whether the actual traffic flow state score of this type of traffic flow turning is greater than or equal to the slow traffic flow state score threshold.

[0117] In this embodiment, when the actual traffic flow state score of a certain traffic flow turn in the current signal control cycle is less than the congested traffic flow state score threshold, the traffic signal control device 100 can further detect whether the actual traffic flow state score of this type of traffic flow turn is greater than or equal to the slow traffic flow state score threshold, in order to determine whether the overall traffic flow state represented by the actual traffic flow state score belongs to a slow traffic flow state or a smooth traffic flow state. Specifically, if the actual traffic flow state score of a certain traffic flow turn is greater than or equal to the slow traffic flow state score threshold, the traffic signal control device 100 will execute sub-step S244 for that type of traffic flow turn; otherwise, the traffic signal control device 100 will execute sub-step S245 for that type of traffic flow turn.

[0118] Sub-step S244: Determine that the traffic flow turning of this type belongs to the slow traffic flow state in the overall traffic flow state of the current signal control cycle.

[0119] Sub-step S245 determines that the traffic flow turning is in a smooth traffic flow state in the current signal control cycle.

[0120] Therefore, this application can accurately identify the overall traffic flow status of any traffic flow turning in the current signal control cycle by executing the above sub-steps S241 to S245.

[0121] This application can deeply consider the impact of traffic flow volatility on the process of traffic flow state recognition at intersections by executing the above steps S210 to S240, so as to ensure that the final traffic flow state recognition result for different traffic flow turning at any intersection can effectively reflect the overall change trend of the real intersection traffic flow state in the time dimension, thereby improving the accuracy of intersection traffic flow state recognition and providing a strong and accurate decision-making basis for adjusting the signal timing scheme based on the intersection traffic flow state.

[0122] Alternatively, please refer to Figure 6 , Figure 6 This is the second flowchart illustrating the intersection traffic flow state recognition method provided in this application embodiment. In this application embodiment, [the method is related to...]. Figure 2 Compared to the intersection traffic flow status recognition method shown, Figure 6The intersection traffic flow state identification method shown may also include steps S250 to S280, to adaptively simulate and select a target traffic flow state scoring rule that is compatible with the target intersection based on the historical traffic data (including historical traffic flow data) of the target intersection, so as to improve the accuracy of the intersection traffic flow state identification of the target intersection and provide a more accurate decision basis for signal timing scheme adjustment operations.

[0123] Step S250: Based on multiple preset score distribution constraints, traffic flow state scoring rules are constructed to obtain multiple candidate traffic flow state scoring rules.

[0124] In this embodiment, all of the multiple candidate traffic flow state scoring rules satisfy the multiple preset score distribution constraints, wherein the multiple preset score distribution constraints may include, but are not limited to:

[0125] (1) "If the actual saturation intervals of each of the m consecutive signal control cycles all belong to the saturation interval of the slow traffic state, then the actual traffic flow state score of the last signal control cycle among these m signal control cycles will be no less than the slow traffic flow state score threshold but less than the congested traffic flow state score threshold, and the overall traffic flow state of the last signal control cycle belongs to the slow traffic flow state." In this case, the constraint condition can be expressed as "e≤m×a". <f”;

[0126] (2) "If the true saturation intervals of each of the n consecutive signal control cycles all belong to the traffic slow-moving state saturation interval, then the true traffic flow state score of the last signal control cycle among these n signal control cycles will be less than the slow-moving traffic flow state score threshold, and the overall traffic flow state of the last signal control cycle belongs to the slow-moving traffic flow state, where n is used to represent the number of consecutive cycles in the second cycle, and the number of consecutive cycles in the second cycle is less than the number of consecutive cycles in the first cycle." In this case, the constraint condition can be expressed as "n×a". <e”;

[0127] (3) "If the true saturation interval of each of the m consecutive signal control cycles belongs to the traffic congestion state saturation interval, then the true traffic flow state score of the last signal control cycle among these m signal control cycles will not be less than the congestion traffic flow state score threshold, and the overall traffic flow state of the last signal control cycle belongs to the congestion traffic flow state". At this time, the constraint condition can be expressed as "m×b≥f".

[0128] (4) "If the actual saturation intervals of each of the n consecutive signal control cycles all belong to the traffic congestion saturation interval, then the actual traffic flow state score of the last signal control cycle among these n signal control cycles will be no less than the slow traffic flow state score threshold but less than the congested traffic flow state score threshold, and the overall traffic flow state of the last signal control cycle belongs to the slow traffic flow state." In this case, the constraint condition can be expressed as "e≤n×b". <f”;

[0129] (5) "If the actual saturation intervals of each of the n consecutive signal control cycles belong to the saturation interval of the slow traffic state, and then the actual saturation intervals of each of the mn consecutive signal control cycles belong to the saturation interval of the congested traffic state, then the actual traffic flow state score of the last signal control cycle among these m signal control cycles will be no less than the slow traffic flow state score threshold but less than the congested traffic flow state score threshold, and the overall traffic flow state of the last signal control cycle belongs to the slow traffic flow state." In this case, the constraint condition can be expressed as "e≤n×a+(mn)×b". <f”;

[0130] (6) "If the actual saturation interval of each of the mn consecutive signal control cycles belongs to the saturation interval of slow traffic, and then the actual saturation interval of each of the n consecutive signal control cycles belongs to the saturation interval of congested traffic, then the actual traffic flow state score of the last signal control cycle in these m signal control cycles will not be less than the congested traffic flow state score threshold, and the overall traffic flow state of the last signal control cycle belongs to the congested traffic flow state." At this time, the constraint condition can be expressed as "(mn)×a+n×b≥f".

[0131] (7) "If the overall traffic flow state of a certain signal control cycle is a congested traffic flow state, and the actual saturation intervals of each of the next n consecutive signal control cycles are all within the saturation intervals of the smooth traffic flow state, then the actual traffic flow state score of the last signal control cycle among these n signal control cycles will be no less than the slow traffic flow state score threshold but less than the congested traffic flow state score threshold, and the overall traffic flow state of the last signal control cycle is a slow traffic flow state." In this case, the constraint condition can be expressed as "e≤m×bn×c". <f”;

[0132] (8) "If the overall traffic flow state of a certain signal control cycle belongs to the congested traffic flow state and the actual saturation interval of each of the next n-1 consecutive signal control cycles belongs to the saturation interval of the smooth traffic state, then the actual traffic flow state score of the last signal control cycle in these n-1 signal control cycles will not be less than the congested traffic flow state score threshold, and the overall traffic flow state of the last signal control cycle belongs to the congested traffic flow state". At this time, the constraint condition can be expressed as "m×b-(n-1)×c≥f";

[0133] (9) "If the overall traffic flow state of a certain signal control cycle is a slow traffic flow state, and the actual saturation intervals of each of the following n-1 consecutive signal control cycles are all within the saturation intervals of the smooth traffic flow state, then the actual traffic flow state score of the last signal control cycle among these n-1 signal control cycles will be no less than the slow traffic flow state score threshold but less than the congested traffic flow state score threshold, and the overall traffic flow state of the last signal control cycle is a slow traffic flow state." In this case, the constraint condition can be expressed as "e≤m×a-(n-1)×c". <f”;

[0134] (10) "If the overall traffic flow state of a certain signal control cycle is a slow traffic flow state, and the actual saturation intervals of each of the next n consecutive signal control cycles are all within the saturation intervals of the smooth traffic flow state, then the actual traffic flow state score of the last signal control cycle among these n signal control cycles will be less than the slow traffic flow state score threshold, and the overall traffic flow state of the last signal control cycle is a smooth traffic flow state." In this case, the constraint condition can be expressed as "m×an×c". <e”;

[0135] (11) "If the overall traffic flow state of a certain signal control cycle belongs to the congested traffic flow state and the actual saturation interval of each of the next n-1 consecutive signal control cycles belongs to the traffic slow-moving state saturation interval, then the actual traffic flow state score of the last signal control cycle in these n-1 signal control cycles will not be less than the congested traffic flow state score threshold, and the overall traffic flow state of the last signal control cycle belongs to the congested traffic flow state". At this time, the constraint condition can be expressed as "m×b-(n-1)×d≥f";

[0136] (12) "If the overall traffic flow state of a certain signal control cycle is a congested traffic flow state, and the actual saturation intervals of each of the next n consecutive signal control cycles are all within the saturation intervals of the smooth traffic flow state, then the actual traffic flow state score of the last signal control cycle among these n signal control cycles will be no less than the slow traffic flow state score threshold but less than the congested traffic flow state score threshold, and the overall traffic flow state of the last signal control cycle is a slow traffic flow state." In this case, the constraint condition can be expressed as "e≤m×bn×d". <f”;

[0137] (13) "If the overall traffic flow state of a certain signal control cycle is a congested traffic flow state, and the actual saturation intervals of each of the next m+1 signal control cycles are all within the saturation intervals of the smooth traffic flow state, then the actual traffic flow state score of the last signal control cycle among these m+1 signal control cycles will be less than the threshold for the slow traffic flow state score, and the overall traffic flow state of the last signal control cycle is considered to be a smooth traffic flow state." In this case, the constraint condition can be expressed as "m×b-(m+1)×d". <e”;

[0138] (14) "If the lane traffic status remains consistent for each of the m+1 consecutive signal control cycles, then the actual traffic flow status score of the last signal control cycle in these m+1 signal control cycles is consistent with the actual traffic flow status score of the second to last signal control cycle (i.e. the signal control cycle preceding the last signal control cycle), wherein the historical traffic flow status of the second to last signal control cycle is consistent with the lane traffic status."

[0139] Therefore, the traffic signal control device 100 can, given multiple consecutive number combinations of cycles (where each consecutive number combination of cycles uses two numbers to represent the first consecutive number of cycles and the second consecutive number of cycles respectively, for example, the consecutive number combination of cycles (m,n) can be, but is not limited to: (3,2), (4,3), (6,4) and (7,4)), jointly solve the above-mentioned multiple preset score distribution constraints for each consecutive number combination of cycles, to obtain the first score accumulation value, the second score accumulation value, the first score decay value, the second score decay value, the slow traffic flow state score threshold and the congested traffic flow state score threshold that match the consecutive number combination of cycles, so as to integrate the consecutive number combination of cycles with the matched first score accumulation value, the second score accumulation value, the first score decay value, the second score decay value, the slow traffic flow state score threshold and the congested traffic flow state score threshold to obtain a candidate traffic flow state scoring rule.

[0140] Step S260: Based on at least one week of historical traffic flow data at the target intersection, construct a signal timing scheme library for the target intersection.

[0141] In this embodiment, the signal timing scheme library includes signal timing schemes for the target intersection under different combinations of traffic flow states when turning. Each combination of traffic flow states when turning is at the target intersection consists of any one of the following traffic flow states: slow-moving, congested, or free-flowing. For example, taking a four-lane signalized intersection as an example, it may include the following combinations of traffic flow states: "The northbound left-turn flow, northbound straight-through flow, southbound left-turn flow, and southbound straight-through flow are all in free-flowing state, while the northbound right-turn flow and southbound right-turn flow are both in slow-moving state; the eastbound left-turn flow, eastbound straight-through flow, westbound left-turn flow, and westbound straight-through flow are all in congested state, while the eastbound right-turn flow and westbound right-turn flow are both in slow-moving state." "Right-turn traffic is flowing smoothly," "Left-turn traffic at the north entrance, straight-through traffic at the north entrance, and straight-through traffic at the south entrance are all flowing smoothly, while right-turn traffic at the north entrance, left-turn traffic at the south entrance, and right-turn traffic at the south entrance are all flowing slowly; left-turn traffic at the east entrance and straight-through traffic at the west entrance are congested, while right-turn traffic at the east entrance, straight-through traffic at the east entrance, left-turn traffic at the west entrance, and right-turn traffic at the west entrance are all flowing smoothly," etc.

[0142] Alternatively, please refer to Figure 7 , Figure 7 yes Figure 6 The flowchart of step S260 is shown below. In this embodiment of the application, step S260 may include sub-steps S261 to S265 to construct a signal timing scheme library adapted to the actual traffic conditions of the target intersection based on historical traffic data (including historical traffic flow data) of the target intersection.

[0143] Sub-step S261: For each type of traffic flow turning at the target intersection, extract the 75th percentile flow value of the off-peak flow data corresponding to that type of traffic flow turning from the historical traffic flow data, as the overall flow value of the smooth traffic flow turning, and extract the 50th percentile flow value of the peak flow data corresponding to that type of traffic flow turning from the historical traffic flow data, as the overall flow value of the congested traffic flow turning.

[0144] Sub-step S262: Extract the 50th percentile flow value of the effective flow data in the historical traffic flow data that corresponds to the type of traffic flow turning and is in a smooth state and a congested state, and use it as the overall flow value of the slow state for the type of traffic flow turning.

[0145] Sub-step S263: Divide the overall flow rate value of the smooth traffic flow, slow traffic flow, and congested traffic flow of this type of traffic flow turning by the total number of lanes at the target intersection for this type of traffic flow turning, to obtain the reference flow rate value corresponding to the smooth traffic flow, slow traffic flow, and congested traffic flow states for this type of traffic flow turning.

[0146] Sub-step S264: For each combination of traffic flow turning and traffic flow state, calculate the phase flow value of each traffic phase at the target intersection under the combination of traffic flow turning and traffic flow state, based on the reference flow value of each traffic flow turning under different traffic flow state.

[0147] In this embodiment, for any combination of traffic flow turning states, the specific traffic flow turning groups involved in each traffic phase at the target intersection can be determined as the traffic flow state content at that combination of traffic flow turning states. Then, for each traffic phase, the maximum flow value among the reference flow values ​​adapted to the combination of traffic flow turning states for all the traffic flow turning states involved is taken as the phase flow value of that traffic phase under the corresponding combination of traffic flow turning states.

[0148] Sub-step S265: Based on the phase flow values ​​of various traffic phases at the target intersection under the combination of traffic flow turning state, calculate the signal control cycle duration and green light duration to obtain the signal timing scheme of the target intersection under the combination of traffic flow turning state.

[0149] In this embodiment, the signal timing scheme for the target intersection under any combination of traffic flow turning states includes the signal control cycle duration shared by all traffic phases at the target intersection, and the actual green light duration for all traffic phases within the same signal control cycle. The calculation formula for the duration of a single signal control cycle at the target intersection can be expressed as follows:

[0150]

[0151] Wherein, C represents the duration of a single signal control cycle at the target intersection, L represents the total loss duration of the target intersection within a single signal control cycle, and L represents the sum of the flow ratios of all traffic phases at the target intersection, wherein the flow ratio of a single traffic phase is the ratio between the phase flow value and the saturation flow value of that traffic phase.

[0152] Furthermore, the actual green light duration for the i-th traffic phase at the target intersection within a single signal control cycle can be expressed by the following formula:

[0153]

[0154] Where C represents the duration of a single signal control cycle at the target intersection, g i ' is used to represent the actual green light duration of the i-th traffic phase at the target intersection within a single signal control cycle, y i Used to represent the flow ratio of the i-th traffic phase at the target intersection.

[0155] Therefore, by executing the above sub-steps S261 to S265, this application can construct a signal timing scheme library that is adapted to the actual traffic conditions of the target intersection based on the historical traffic data (including historical traffic flow data) of the target intersection.

[0156] Step S270: Multiple candidate traffic flow state scoring rules are used as traffic flow state evaluation criteria for the target intersection, and the signal timing scheme library is called to perform signal control simulation on the target intersection based on the traffic flow state evaluation criteria, so as to determine the rule adaptability of each of the multiple candidate traffic flow state scoring rules at the target intersection.

[0157] In this embodiment, the traffic signal control device 100 can use the multiple candidate traffic flow state scoring rules as the traffic flow state evaluation criteria for the target intersection. Then, during the signal control simulation, it uses the determined traffic flow state evaluation criteria to identify the intersection traffic flow results on a cycle-by-cycle basis. Next, it calls the signal timing scheme from the signal timing scheme library that matches the traffic flow results of the intersection as the signal timing scheme to be used in the next cycle for traffic signal control simulation. This allows for the evaluation of the signal evaluation index value of the corresponding traffic flow state scoring rule during the traffic signal control simulation process. The signal evaluation index value is then used to characterize the rule fit of the corresponding candidate traffic flow state scoring rule at the target intersection. Specifically, if a positive evaluation index (e.g., vehicle throughput efficiency) is used to evaluate the signal evaluation index value, the rule fit will increase as the signal evaluation index value increases; conversely, if a negative evaluation index (e.g., total vehicle delay) is used to evaluate the signal evaluation index value, the rule fit will decrease as the signal evaluation index value increases.

[0158] Step S280: Select the candidate traffic flow state scoring rule with the highest matching degree as the target traffic flow state scoring rule that matches the target intersection.

[0159] In this embodiment, after determining the rule fit of each of the multiple candidate traffic flow state scoring rules at the target intersection, the candidate traffic flow state scoring rule with the largest rule fit can be selected from the multiple candidate traffic flow state scoring rules as the valid traffic flow state scoring rule (i.e., the target traffic flow state scoring rule) that needs to be stored at the traffic signal control device 100 at the target intersection.

[0160] Therefore, by executing the above steps S250 to S280, this application can adaptively simulate and select a target traffic flow state scoring rule that is compatible with the target intersection based on the historical traffic data (including historical traffic flow data) of the target intersection, thereby improving the accuracy of the intersection traffic flow state identification of the target intersection and providing a more accurate decision basis for signal timing scheme adjustment operations.

[0161] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0162] Furthermore, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part. If the various functions provided in this application are implemented in the form of software functional modules and sold or used as independent products, they can be stored in a storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (e.g., a server, personal computer, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application as the traffic signal control device 100. The aforementioned readable storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks.

[0163] The above descriptions are merely various embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application shall be determined by the scope of the claims.

Claims

1. A method for recognizing traffic flow status at an intersection, characterized in that, The method includes: Obtain the maximum saturation flow rate of various traffic flow turns at the target intersection, as well as the actual traffic signal control data of the various traffic flow turns in the current signal control cycle; For each type of traffic flow turn at the target intersection, the actual saturation of that type of traffic flow turn in the current signal control cycle is calculated based on the maximum saturation rate of that type of traffic flow turn and the actual signal control traffic data. Based on the target traffic flow state scoring rules adapted to the target intersection, and based on the actual saturation of the traffic flow turning and the historical traffic flow state score of the traffic flow turning in the previous signal control cycle in the current signal control cycle, the actual traffic flow state score of the traffic flow turning in the current signal control cycle is calculated. According to the target traffic flow state scoring rule, the actual traffic flow state score of this type of traffic flow turning is used to identify the traffic flow state, and the overall traffic flow state of this type of traffic flow turning in the current signal control cycle is obtained. The target traffic flow state scoring rule records a first cycle consecutive number, a first score accumulation value directly corresponding to the traffic slow-moving state saturation interval, a second score accumulation value corresponding to the traffic congestion state saturation interval, a first score decay value corresponding to the traffic smooth state saturation interval, and a second score decay value corresponding to the traffic slow-moving state saturation interval and the congested traffic flow state. The step of calculating the actual traffic flow state score of the traffic flow turning in the current signal control cycle based on the actual saturation of the traffic flow turning and the historical traffic flow state score of the traffic flow turning in the previous signal control cycle, according to the target traffic flow state scoring rule adapted to the target intersection, includes: For this type of traffic flow turning, the target saturation range corresponding to the actual saturation is determined in the saturation range of slow traffic, smooth traffic, and congested traffic. Based on the target saturation range, it is detected whether the actual saturation ranges of each of the target period consecutively for the current signal control period are consistent, and whether the lane traffic state represented by the target saturation range is consistent with the historical traffic flow state represented by the historical traffic flow state score, wherein the number of consecutive target periods is obtained by adding one to the number of consecutive first periods; If the true saturation range of each of the target cycle consecutive signal control cycles is consistent, and the lane traffic state represented by the target saturation range is consistent with the historical traffic flow state represented by the historical traffic flow state score, then the historical traffic flow state score is directly used as the actual traffic flow state score of this type of traffic flow turning in the current signal control cycle; otherwise, a target state score matching the target saturation range is calculated based on the historical traffic flow state score, and the calculated target state score is used as the actual traffic flow state score of this type of traffic flow turning in the current signal control cycle. The step of calculating the target state score matching the target saturation interval based on the historical traffic flow state score includes: If the target saturation range falls within the traffic congestion state saturation range, the historical traffic flow state score and the second accumulated score are added together to obtain the target state score. If the target saturation range falls within the traffic flow saturation range, the historical traffic flow state score and the first score decay value are subtracted to obtain the target state score. If the target saturation range falls within the traffic slow-moving state saturation range, it is detected whether the historical traffic flow state represented by the historical traffic flow state score belongs to the congested traffic flow state. If the historical traffic flow status is detected to be a congested traffic flow status, the historical traffic flow status score and the second score attenuation value are subtracted to obtain the target status score; otherwise, the historical traffic flow status score and the first score accumulation value are added to obtain the target status score.

2. The method according to claim 1, characterized in that, The step of obtaining the maximum saturation flow rate for various traffic flow turning directions at the target intersection includes: For each type of traffic flow turning at the target intersection, the saturation flow rate is calculated based on the lane flow data and green light duration for that type of traffic flow turning in multiple historical signal control cycles, and the historical saturation flow rate corresponding to that type of traffic flow turning in multiple historical signal control cycles is obtained. The historical saturation flow rate corresponding to this type of traffic flow turning in multiple historical signal control periods was statistically analyzed, and the 90th percentile saturation flow rate in the corresponding statistical results was taken as the maximum saturation flow rate of this type of traffic flow turning.

3. The method according to claim 1, characterized in that, The target intersection at the first Traffic flow turning in the first The saturation flow rate for each signal control cycle is calculated using the following formula: ； in, Used to represent the first Traffic flow turning in the first Saturation flow rate per signal control cycle Used to represent the first Traffic flow turning in the first The green light duration for each signal control cycle Used to represent the first The total number of lanes at the target intersection where traffic flow turns. Used to represent the first Traffic flow turning in the first In the lane flow data of the first traffic control cycle Traffic flow rate per lane.

4. The method according to claim 1, characterized in that, The actual traffic signal control data for each traffic flow turning direction includes the current signal control cycle duration, actual green light duration, and actual traffic flow value for each lane. Therefore, at the target intersection, the first... The traffic saturation of the traffic flow turning direction in the current signal control cycle is calculated using the following formula: ； in, Used to represent the first Traffic flow shifts at the current traffic saturation level during the signal control cycle. Used to represent the first The maximum saturation flow rate for traffic flow turning. Used to represent the first The actual green light duration for different traffic flow directions during the current signal control cycle. Used to represent the first The current signal control cycle duration for traffic flow turning. Used to represent the first The total number of lanes at the target intersection where traffic flow turns. Used to represent the first The first type of traffic flow turning The actual traffic flow value of each lane in the current traffic control cycle. Used to represent the first The green ratio of traffic flow shifts in the current traffic control cycle.

5. The method according to claim 1, characterized in that, The target traffic flow state scoring rule records a slow traffic flow state score threshold and a congested traffic flow state score threshold. The step of identifying the traffic flow state based on the actual traffic flow state score of this type of traffic flow turning according to the target traffic flow state scoring rule, and obtaining the overall traffic flow state of this type of traffic flow turning in the current signal control cycle, includes: Detect whether the actual traffic flow state score of this type of traffic flow turning is greater than or equal to the congested traffic flow state score threshold; If the actual traffic flow status score of the traffic flow turning is detected to be greater than or equal to the congested traffic flow status score threshold, then it is determined that the overall traffic flow status of the traffic flow turning in the current signal control cycle belongs to the congested traffic flow status; otherwise, it is detected whether the actual traffic flow status score of the traffic flow turning is greater than or equal to the slow traffic flow status score threshold. If the actual traffic flow state score of the detected traffic flow turning is greater than or equal to the slow traffic flow state score threshold, it is determined that the overall traffic flow state of the traffic flow turning in the current signal control cycle belongs to the slow traffic flow state. If the actual traffic flow state score of the detected traffic flow turning is less than the slow traffic flow state score threshold, it is determined that the overall traffic flow state of the traffic flow turning in the current signal control cycle belongs to the smooth traffic flow state.

6. The method according to any one of claims 1-5, characterized in that, The method further includes: Traffic flow state scoring rules are constructed based on multiple preset score distribution constraints to obtain multiple candidate traffic flow state scoring rules. Based on at least one week of historical traffic flow data at the target intersection, a signal timing scheme library for the target intersection is constructed. The signal timing scheme library includes signal timing schemes for the target intersection under different combinations of traffic flow turning states. Each combination of traffic flow turning states consists of any one of the traffic flow states of slow traffic flow, congested traffic flow, and unobstructed traffic flow at the target intersection. The multiple candidate traffic flow state scoring rules are used as the traffic flow state evaluation criteria for the target intersection, and the signal timing scheme library is called to perform signal control simulation on the target intersection based on the traffic flow state evaluation criteria, so as to determine the rule fit degree of each of the multiple candidate traffic flow state scoring rules at the target intersection. The candidate traffic flow state scoring rule with the highest matching degree is selected as the target traffic flow state scoring rule that matches the target intersection.

7. The method according to claim 6, characterized in that, The step of constructing a signal timing scheme library for the target intersection based on at least one week of historical traffic flow data at the target intersection includes: For each type of traffic flow turn at the target intersection, the 75th percentile flow value of the off-peak flow data corresponding to that type of traffic flow turn is extracted from the historical traffic flow data as the overall flow value for the smooth flow state of that type of traffic flow turn, and the 50th percentile flow value of the peak flow data corresponding to that type of traffic flow turn is extracted from the historical traffic flow data as the overall flow value for the congested flow state of that type of traffic flow turn. Extract the 50th percentile flow value of the effective flow data in the historical traffic flow data that corresponds to this type of traffic flow turning and is in a smooth state and a congested state, and use it as the overall flow value of the slow state for this type of traffic flow turning. Divide the overall traffic flow value of the smooth traffic flow, slow traffic flow, and congested traffic flow of this type of traffic flow turn by the total number of lanes at the target intersection to obtain the reference traffic flow value corresponding to the smooth traffic flow, slow traffic flow, and congested traffic flow states, respectively. For each combination of traffic flow turning states, based on the reference flow values ​​of each traffic flow turning state under different traffic flow states, the phase flow values ​​of various traffic phases at the target intersection under that combination of traffic flow turning states are calculated. Based on the phase flow values ​​of various traffic phases at the target intersection under this combination of traffic flow turning states, the signal control cycle duration and green light duration are calculated to obtain the signal timing scheme of the target intersection under this combination of traffic flow turning states.

8. A traffic signal control device, characterized in that, The control device includes a processor and a memory, the memory storing a computer program that can be executed by the processor, and the processor can execute the computer program to implement the intersection traffic flow state recognition method according to any one of claims 1-7.

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