Method and apparatus for regulating traffic signals

Abstract

The present disclosure relates to a traffic signal regulation method and device, the method comprising: acquiring a target congestion section and a section state of the target congestion section; calculating, under a current intersection signal timing scheme, an outgoing traffic capacity of a downstream intersection corresponding to the target congestion section in a preset unit time, and an incoming traffic capacity of an upstream intersection in the preset unit time; subtracting the incoming traffic capacity from the outgoing traffic capacity to obtain a traffic capacity difference of the target congestion section; determining a target control mode of the target congestion section according to the traffic capacity difference and the section state; and generating a target intersection signal timing scheme corresponding to the target congestion section based on the target control mode and a traffic volume to be dissipated of the target congestion section, and executing the target intersection signal timing scheme. The present disclosure can improve the traffic signal regulation efficiency.

Description

Technical Field

[0001] This disclosure relates to the field of traffic signal management technology, and in particular to a method and apparatus for controlling traffic signals. Background Technology

[0002] Urban traffic congestion is a common problem plaguing major cities, especially during morning and evening rush hours. Optimizing signal timing is one of the important means to alleviate congestion.

[0003] Currently, signal timing adjustments for peak congestion scenarios are mainly achieved through manual monitoring. This involves traffic management personnel observing road conditions via video surveillance, manually calculating and issuing timing plans based on experience. This method suffers from slow response times, high labor costs, and heavy reliance on individual experience, resulting in low overall efficiency. Alternatively, automatic control is based on fixed preset targets. This involves calculating timing plans based on real-time monitoring data for specific intersections, arterial roads, or areas. However, this method is limited to preset targets and cannot automatically cover congestion in non-preset road sections, thus limiting the scope of congestion mitigation. Consequently, the efficiency and adaptability of traffic signal control fail to meet the needs of practical applications.

[0004] Therefore, how to improve the efficiency of traffic signal control during peak traffic congestion periods in cities has become an urgent problem to be solved. Summary of the Invention

[0005] To solve the above-mentioned technical problems, or at least partially solve them, this disclosure provides a traffic signal control method and apparatus that can improve the efficiency of traffic signal control.

[0006] Firstly, this disclosure provides a method for controlling traffic signals, including: Obtain the target congested road segment and its road segment status; Calculate the outbound traffic capacity of the downstream intersection corresponding to the target congested road segment in a preset unit time, and the inbound traffic capacity of the upstream intersection in the same preset unit time, under the current intersection signal timing scheme. The difference between the inbound traffic capacity and the outbound traffic capacity is calculated to obtain the traffic capacity difference of the target congested road segment; Based on the poor traffic capacity and the road segment status, the target control method for the target congested road segment is determined; the target control method is: upstream intersection traffic control and / or downstream intersection traffic control. Based on the target control method and the traffic volume to be dissipated in the target congested road segment, a target intersection signal timing scheme corresponding to the target congested road segment is generated and executed; The traffic volume to be dissipated is represented as the total number of vehicles queuing on the target congested road section that are reduced through control measures within the preset unit time.

[0007] As an optional implementation of this invention, obtaining the target congested road segment includes: Acquire real-time traffic data for each road segment in the urban road network, and determine the status of each road segment based on the real-time traffic data; Based on the road segment status of each road segment, the target congested road segment is obtained.

[0008] As an optional implementation of this invention, the calculation of the outbound traffic capacity of the downstream intersection corresponding to the target congested road segment and the inbound traffic capacity of the upstream intersection within the same preset unit time, under the current intersection signal timing scheme, includes: For downstream intersections, obtain the cycle duration under the current intersection signal timing scheme, the green light duration of the control phase corresponding to the outbound direction of the target congested road segment, and the saturation headway and number of lanes for the corresponding lanes; The exit capacity is calculated based on the ratio of the green light duration to the cycle duration, the saturation headway, and the number of lanes. For the upstream intersection, obtain the cycle duration under the current intersection signal timing scheme, the green light duration of the control phase corresponding to the direction of entry of the target congested road segment, and the saturation headway and number of lanes of the corresponding lane; The entry capacity is calculated based on the ratio of the green light duration to the cycle duration, the saturation headway, and the number of lanes.

[0009] As an optional implementation of this invention, the step of determining the target control method for the target congested road segment based on the traffic capacity difference and the road segment status includes: If the difference in traffic capacity is less than or equal to zero, then the upstream intersection interception method will be used for control. If the difference in traffic capacity is greater than zero and the road segment is in a congested state, then it is determined that the downstream intersection access method will be used for control. If the traffic capacity difference is greater than zero and the road segment is in a state of severe congestion, then it is determined that the downstream intersection traffic control and the upstream intersection traffic interception control will be implemented in parallel.

[0010] As an optional implementation of this invention, before determining and executing the intersection signal timing adjustment scheme corresponding to the target congested road segment based on the control method and the traffic volume to be dissipated in the congested road segment, the method further includes: Obtain the congestion length and number of lanes of the target congested road segment; The traffic volume to be dispersed is calculated based on the congestion length, the number of lanes, and the congestion dissipation rate per unit time.

[0011] As an optional implementation of this invention, the step of generating and executing a target intersection signal timing scheme corresponding to the target congested road segment based on the target control method and the traffic volume to be dissipated in the target congested road segment includes: The control intersections and corresponding control flow directions are determined based on the target control method. Based on the current signal timing scheme of the controlled intersection, determine the control phase corresponding to the control flow direction and the green light duration, cycle duration, number of lanes and headway of the control phase in the current timing scheme; The green light adjustment amount of the control phase is calculated based on the traffic volume to be dissipated, the green light duration, the cycle duration, the number of lanes, and the headway. The signal timing scheme for the current intersection is adjusted according to the green light adjustment amount, and the signal timing scheme for the target intersection is generated and executed.

[0012] As an optional implementation of this invention, when the target control method is upstream intersection traffic control, the step of calculating the green light adjustment amount of the control phase based on the traffic volume to be dissipated, the green light duration, the cycle duration, the number of lanes, and the headway includes: The green light duration after the control phase compression is determined based on the green light duration, corresponding number of lanes, saturated headway, cycle duration of the control phase in the current timing scheme, and the traffic volume to be dissipated. The compressed green light duration of the control phase satisfies the constraint that it is not less than the minimum green light duration of the corresponding phase.

[0013] As an optional implementation of this invention, when the target control method is downstream intersection control, the step of calculating the green light adjustment amount of the control phase based on the traffic volume to be dissipated, the green light duration, the cycle duration, the number of lanes, and the headway includes: The green light duration after adding the control phase is determined based on the green light duration, corresponding number of lanes, saturation headway, and cycle duration of the control phase in the current timing scheme, as well as the traffic volume to be dissipated. The duration of the green light in the control phase after the addition satisfies the constraint that it is not less than the minimum green light duration of the corresponding phase.

[0014] As an optional implementation of this invention, when the control method is upstream intersection traffic control and downstream intersection traffic increase control, the step of calculating the green light adjustment amount of the control phase based on the traffic volume to be dissipated, the green light duration, the cycle duration, the number of lanes, and the headway includes: The traffic volume to be dispersed is allocated into a diversion control volume and an additional release control volume; Using the aforementioned traffic diversion control volume as the traffic volume to be dissipated, the green light adjustment amount for each control phase upstream is calculated according to the aforementioned method; Using the aforementioned additional control quantity as the traffic volume to be dissipated, the green light adjustment quantity for each downstream control phase is calculated according to the aforementioned method.

[0015] Secondly, a traffic signal control device is provided, the device comprising: The acquisition unit is used to acquire the target congested road segment and the road segment status of the target congested road segment; The calculation unit is used to calculate the outbound traffic capacity of the downstream intersection corresponding to the target congested road segment in a preset unit time, and the inbound traffic capacity of the upstream intersection in the same preset unit time, under the current intersection signal timing scheme. The processing unit is used to calculate the difference between the inbound traffic capacity and the outbound traffic capacity to obtain the traffic capacity difference of the target congested road segment; The determining unit is used to determine the target control method for the target congested road segment based on the traffic capacity difference and the road segment status; the target control method is: upstream intersection traffic control and / or downstream intersection traffic control. The generation unit is used to generate and execute the target intersection signal timing scheme corresponding to the target congested road segment based on the target control method and the traffic volume to be dissipated in the target congested road segment. The traffic volume to be dissipated is represented as the total number of vehicles queuing on the target congested road section that are reduced through control measures within the preset unit time.

[0016] Thirdly, a computer-readable storage medium is provided, comprising: storing a computer program on the computer-readable storage medium, wherein when the computer program is executed by a processor, it implements the traffic signal control method as described in the first aspect.

[0017] Fourthly, an electronic device is provided, comprising: one or more processors; and a storage device for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the traffic signal control method as described in the first aspect.

[0018] Fifthly, a computer program product is provided, comprising: when the computer program product is run on a computer, causing the computer to implement the traffic signal control method as shown in the second aspect.

[0019] Compared with the prior art, the technical solution provided in this disclosure has the following advantages: By acquiring the target congested road segment and its status, and calculating the outbound capacity of the downstream intersection and the inbound capacity of the upstream intersection corresponding to the target congested road segment under the current timing scheme, the difference between the inbound capacity and the outbound capacity is obtained to obtain the capacity difference. Then, based on the capacity difference and the road segment status, the upstream intersection traffic control and / or the downstream intersection traffic control are determined as the target control methods. Finally, the target intersection signal timing scheme is automatically generated and executed based on the target control method and the traffic volume to be dissipated. The entire process does not require manual intervention, avoiding the problems of reliance on manual experience and response lag. At the same time, since the calculation of the capacity difference and the selection of the control method do not depend on the preset specific intersection or area objects, but are dynamically adapted according to the real-time road segment status and the capacity difference, it can cover any road segment in the road network that is congested, breaking through the limitations of preset objects and significantly improving the efficiency and scenario adaptability of traffic signal control. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0021] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0022] Figure 1 This is a hardware configuration block diagram of a computer device according to one or more embodiments of the present disclosure; Figure 2 This is a software configuration block diagram of a computer device according to one or more embodiments of the present disclosure; Figure 3 This is one of the flowcharts illustrating a traffic signal control method provided in this embodiment of the present disclosure; Figure 4 A second schematic flowchart illustrating a traffic signal control method provided in this embodiment of the present disclosure; Figure 5 A third schematic flowchart illustrating a traffic signal control method provided in this embodiment of the present disclosure; Figure 6 One of the road diagrams illustrating a traffic signal control method provided in this embodiment of the present disclosure; Figure 7 A second road diagram illustrating a traffic signal control method provided in this embodiment of the present disclosure; Figure 8A fourth schematic flowchart illustrating a traffic signal control method provided in this embodiment of the present disclosure; Figure 9 A third road diagram illustrating a traffic signal control method provided in this embodiment of the present disclosure; Figure 10 A fourth road diagram illustrating a traffic signal control method provided in this embodiment of the present disclosure; Figure 11 Fifth road diagram illustrating a traffic signal control method provided in this embodiment of the present disclosure; Figure 12 A schematic diagram of the structure of a traffic signal control device provided in an embodiment of this disclosure; Figure 13 This is a schematic diagram of the structure of a computer device provided in an embodiment of this disclosure. Detailed Implementation

[0023] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0024] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0025] The terms "first," "second," "third," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar or related objects or entities, and do not necessarily imply a specific order or sequence, unless otherwise specified. It should be understood that such terms are interchangeable where appropriate.

[0026] The terms “comprising” and “having”, and any variations thereof, are intended to cover but not exclude inclusion, for example, a product or device that includes a range of components is not necessarily limited to all of the components that are clearly listed, but may include other components that are not clearly listed or that are inherent to such product or device.

[0027] To more clearly illustrate the embodiments of this application, the technical terms used in the embodiments will be briefly introduced below.

[0028] Road segment: refers to the road between two adjacent intersections in an urban road network, and has directional attributes. For example, the road segment from intersection A to intersection B is one road segment, and the road segment from intersection B to intersection A is another road segment.

[0029] Phase: The signal display status of one or more traffic flows that simultaneously have the right of way within a signal cycle. For example, allowing simultaneous north-south straight traffic is one phase, and allowing simultaneous east-west left turns is another phase.

[0030] Cycle: The total time required for a traffic light to complete one full cycle (including the green, yellow, and red light times for all phases).

[0031] Minimum Green: The shortest green light time allowed for a given phase. If it is lower than this value, pedestrian safety or normal vehicle passage cannot be guaranteed.

[0032] Saturated headway: Under saturated traffic conditions, the average time interval between two vehicles that pass the stop line consecutively in the same lane reflects the lane's traffic efficiency, measured in seconds. The saturated headway varies for different lane types; for example, it is approximately 2.0 seconds for a straight lane on a main road and approximately 2.67 seconds for a left-turn lane.

[0033] Traffic capacity: The maximum number of vehicles that can pass through a lane or multiple lanes per unit of time. In this application, traffic capacity is calculated in 5-minute units.

[0034] Barrier: A time isolation line in the signal timing model, used to forcibly separate conflicting traffic flows at intersections (such as north-south and east-west traffic), ensuring that traffic flows from different directions are never released at the same time, thus eliminating conflicts in terms of timing.

[0035] The traffic signal control method provided in this disclosure can be implemented based on computer equipment, or functional modules or functional entities in computer equipment.

[0036] The computer equipment can be a personal computer (PC), server, mobile phone, tablet computer, laptop computer, mainframe computer, etc., and this disclosure does not specifically limit it.

[0037] For example, Figure 1 This is a hardware configuration block diagram of a computer device according to one or more embodiments of the present disclosure. Figure 1As shown, the computer device includes at least one of the following: a tuner / demodulator 110, a communicator 120, a detector 130, an external device interface 140, a controller 150, a display 160, an audio output interface 170, a memory, a power supply, and a user interface 180. The controller 150 includes a central processing unit, a video processor, an audio processor, a graphics processor, RAM, ROM, and a first to nth interface for input / output. The display 160 can be at least one of a liquid crystal display, an OLED display, a touch display, and a projection display, and can also be a projection device and a projection screen. The tuner / demodulator 110 receives broadcast television signals via wired or wireless means, and demodulates audio and video signals, such as EPG audio and video data signals, from multiple wireless or wired broadcast television signals. The communicator 120 is a component used to communicate with external devices or servers according to various communication protocol types. For example, the communicator may include at least one of a Wi-Fi module, a Bluetooth module, a wired Ethernet module, other network communication protocol chips or near-field communication protocol chips, and an infrared receiver. The computer equipment can establish the transmission and reception of control signals and data signals with the server or local control equipment through the communicator 120. The detector 130 is used to collect signals from the external environment or to interact with the outside world. The controller 150 and the tuner / demodulator 110 can be located in different separate devices, that is, the tuner / demodulator 110 can also be located in an external device of the main device where the controller 150 is located, such as an external set-top box.

[0038] In some embodiments, the controller 150 controls the operation of the computer device and responds to user operations through various software control programs stored in memory. The controller 150 controls the overall operation of the computer device. The user can input user commands through a graphical user interface (GUI) displayed on the monitor 160, and the user input interface receives the user input commands through the GUI. Alternatively, the user can input user commands by entering specific sounds or gestures, and the user input interface receives the user input commands by recognizing the sounds or gestures through sensors.

[0039] Figure 2 This is a schematic diagram of the software configuration of a computer device according to one or more embodiments of the present disclosure, such as... Figure 2 As shown, the system is divided into four layers, from top to bottom: the Applications layer (referred to as the "Application Layer"), the Application Framework layer (referred to as the "Framework Layer"), the Android runtime and system library layer (referred to as the "System Runtime Library Layer"), and the kernel layer.

[0040] To illustrate this solution in more detail, the following will use examples to illustrate it. Figures 3-10 To explain, it is understandable that, although Figures 3-10 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise explicitly stated in this document, there is no strict order in which these steps are executed; they can be performed in other orders. Furthermore, Figures 3-10 At least a portion of the steps in the flowchart may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but may be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but may be executed alternately or in turn with other steps or at least a portion of the sub-steps or stages of other steps. The aim is to implement the traffic signal control method provided in the embodiments of this disclosure.

[0041] Figure 3 This is one of the flowcharts illustrating a traffic signal control method provided in this embodiment of the disclosure. Figure 3 As shown, the method specifically includes the following steps: S31. Obtain the target congested road segment and the road segment status of the target congested road segment.

[0042] In some embodiments, the urban road network consists of several road segments. A road segment refers to a road between two adjacent intersections in the urban road network and has directional attributes. For example, the direction from intersection A to intersection B is one road segment, and the direction from intersection B to intersection A is another independent road segment. Thus, the road segment is used as the smallest identification unit to independently determine the congestion status of each road segment.

[0043] Specifically, the target congested road segments and their status can be obtained by acquiring real-time traffic data from various road segments in the urban road network; wherein, the real-time traffic data includes parameters such as floating car average speed, average delay time of vehicles in the approach direction, and traffic flow of the road segment.

[0044] In one embodiment, the average speed of floating cars can be used as a parameter for determining the state of a road segment. The average speed of floating cars can be obtained by calculating the average speed of all floating vehicles on each road segment using floating car trajectory data provided by an in-vehicle navigation system, GPS positioning data, or an internet map service provider.

[0045] Optionally, the average delay time of vehicles entering the intersection can also be used as a parameter for determining the road segment status. The average delay time can be calculated from data from roadside radar detectors, video detectors, or electronic police systems, specifically the average waiting time experienced by a vehicle from entering the intersection's approach lane to passing the stop line.

[0046] Furthermore, after obtaining real-time traffic data, the operating status of each road segment is determined according to a preset classification threshold. In this embodiment, the operating status of the road segment is divided into four levels: Level 1 indicates smooth traffic, Level 2 indicates slow traffic, Level 3 indicates congestion, and Level 4 indicates severe congestion.

[0047] Furthermore, refer to Figure 4 As shown, the acquisition of the target congested road segment and the road segment status of the target congested road segment can be further refined into the following S311 and S312: S311. Obtain real-time traffic data for each road segment in the urban road network, and determine the road segment status based on the real-time traffic data.

[0048] The real-time traffic data includes the average speed of floating cars or the average delay time of vehicles traveling in the direction of arrival.

[0049] Specifically, Floating Car Data (FCD) refers to vehicles equipped with GPS positioning devices that can transmit location and speed information in real time, including taxis, ride-hailing vehicles, buses, and vehicles equipped with in-vehicle navigation systems. By receiving a large amount of real-time data transmitted from floating cars, the data is aggregated and matched according to road segments to calculate the average speed of all floating cars on each road segment.

[0050] Furthermore, the average speed of floating cars can be obtained as follows: for a certain road segment, obtain the instantaneous speed or interval speed of all floating cars passing through the road segment within a preset time window, such as 5 minutes. Then, remove outliers, such as a stopped state with a speed of zero or an outlier that clearly exceeds the road speed limit. Then, take the arithmetic mean of the remaining valid speed data to obtain the average speed V of floating cars in the road segment within the preset time window (unit: km / h).

[0051] The average delay time for vehicles entering a specific direction at an intersection refers to the average waiting time experienced by all vehicles entering the intersection from the moment they enter the queue or begin to decelerate until they pass the stop line within a preset time window. The unit is seconds. This parameter directly reflects the signal control delay and traffic congestion experienced by vehicles when passing through the intersection's entrance lanes, and is an important indicator for measuring the intersection's traffic efficiency and service level.

[0052] Specifically, the average delay time of vehicles entering the intersection is obtained by collecting the passage data of each vehicle through fixed detection equipment deployed at the intersection entrance lanes; the fixed detection equipment includes, but is not limited to, radar detectors, video detectors, geomagnetic detectors, coil detectors, and electronic police systems; the above equipment is used to accurately record parameters such as the timestamp of each vehicle's arrival at the stop line or the section it passes through, instantaneous speed, and vehicle type.

[0053] Furthermore, using vehicle identification and tracking technology, the passage times of the same vehicle at the upstream section of the intersection (e.g., the starting position of the approach lane) and the downstream section (e.g., the stop line position) are matched. The difference between the vehicle's passage time at the upstream section and its passage time at the downstream section is the total time the vehicle takes to pass through the approach lane. Subtracting the standard travel time required for the vehicle to pass through the approach lane in free flow (i.e., the approach lane length divided by the free flow speed) from this total time yields the vehicle's waiting time, or delay time, at the intersection's approach lane.

[0054] Then, by comparing real-time data with preset discrimination thresholds, the operating status of each road segment is divided into different levels, thereby achieving an objective quantitative expression of the traffic operating status of the road segment.

[0055] Specifically, the operating status of the road segment includes: smooth traffic can be understood as vehicles driving freely with basically no queues and smooth passage; slow traffic can be understood as vehicles driving at a significantly reduced speed, queues appearing but the queues are short, and the passage efficiency is slightly reduced; congestion can be understood as vehicles driving slowly, queues being long, and the passage efficiency being significantly reduced; severe congestion can be understood as vehicles almost coming to a standstill, queues overflowing or nearly overflowing, and passage nearly interrupted.

[0056] When using floating car average speed as a discrimination parameter, the actual driving experience and congestion level at the same speed will differ depending on the design speed, lane width, isolation conditions, and speed limit standards of different road grades. Therefore, different road grades correspond to different speed discrimination thresholds, as shown in Table 1 below. Table 1 shows the correspondence between floating car average speed and road segment status: Table 1

[0057] Where V represents the average speed of the floating car, in km / h.

[0058] For example, when the average floating car speed of a certain main road segment is 30km / h, the road segment status is determined to be smooth, i.e., level 1, because 30km / h > 25km / h; when the average speed is 8km / h, the road segment status is determined to be congested, i.e., level 3, because 12km / h ≥ 8km / h > 5km / h.

[0059] The specific values ​​of the aforementioned speed thresholds can be calibrated and optimized based on historical traffic data of actual cities. Different cities can make adaptive adjustments based on local driving behavior characteristics, traffic composition (proportion of large vehicles), road geometry, and other factors. This invention does not impose specific limitations on this.

[0060] When the average delay time of vehicles approaching the intersection is used as a criterion, a longer delay time indicates a longer waiting time for vehicles to pass through the intersection's approach lanes, and a more severe degree of congestion. See Table 2 below for details; Table 2 shows the correspondence between the average delay time of vehicles approaching the intersection and road segment conditions. Table 2

[0061] For example, when the average delay time for vehicles in that direction is 30 seconds, the corresponding road segment is determined to be smooth, i.e., level 1, because 30 ≤ 35; when the average delay time is 65 seconds, it is determined to be congested, i.e., level 3, because 55 < 65 ≤ 80.

[0062] S312. Based on the road segment status of each road segment, obtain the target congested road segment.

[0063] Furthermore, based on the operational status level of each road segment determined in S312, road segments in the state of congestion or severe congestion are screened out and identified as target congested road segments that require signal control intervention, serving as the control objects for subsequent steps S32 to S35.

[0064] Based on the aforementioned S311 and S312, by using the average speed of floating cars or the average delay time of vehicles in the approach direction as the basis for determining the road segment status, four types of operating states—smooth, slow, congested, and severely congested—can be quantitatively distinguished. This allows for the objective and accurate identification of truly congested road segments, avoiding the misjudgment problems that can easily arise from a single monitoring indicator. Only congested and severely congested road segments are designated as target congested road segments for subsequent signal control, while smooth and slow-moving road segments that do not require optimization are filtered out. This reduces redundant system calculations, saves computing resources, and allows control resources to be concentrated on congested locations, effectively improving the efficiency of road network congestion management.

[0065] S32. Calculate the outbound traffic capacity of the downstream intersection corresponding to the target congested road segment and the inbound traffic capacity of the upstream intersection within the same preset unit time under the current intersection signal timing scheme.

[0066] In this step, the target congested road segment identified in S31 is taken as the analysis object. The traffic capacity of its downstream intersection to allow vehicles to leave the road segment per unit time under the current intersection signal timing scheme is calculated, as well as the traffic capacity of its upstream intersection to allow vehicles to enter the road segment per unit time under the current intersection signal timing scheme.

[0067] Specifically, the exit capacity refers to the maximum number of vehicles that can be allowed to pass through the intersection from the direction of the congested road segment within a preset unit time, such as 5 minutes, under the current signal timing scheme. The unit is: vehicles / preset unit time, such as vehicles / 5 minutes. This indicator reflects the downstream absorption capacity, that is, how many vehicles can leave the congested road segment per unit time under the current signal timing conditions.

[0068] It should be noted that the currently running signal timing scheme can be any of a timing control scheme, an inductive control scheme, or an adaptive control scheme, and this invention does not specifically limit it. Regardless of the control method used, this invention obtains the currently executed timing parameters from the signal control system in real time.

[0069] In the embodiments of this application, reference is made to Figure 5 As shown, the process of obtaining the outbound traffic capacity of the downstream intersection corresponding to the target congested road segment within a preset unit time, and the inbound traffic capacity of the upstream intersection within the same preset unit time, can be further refined into the following S321-S324: S321. For downstream intersections, obtain the cycle duration under the current intersection signal timing scheme, the green light duration of the control phase corresponding to the outbound direction of the target congested road segment, and the saturation headway and number of lanes for the corresponding lanes.

[0070] Specifically, the downstream intersection refers to the final intersection of the target congested road segment, that is, the next intersection that vehicles reach after exiting the target congested road segment in the direction of travel. (See reference...) Figure 6 The diagram shows a road map of the target congested intersection. The target congested section is the eastbound section 61 from intersection A to intersection B. That is, if a vehicle is traveling from intersection A to intersection B, the downstream intersection is intersection B.

[0071] It's important to note that downstream intersections are the exit points for vehicles exiting the target congested section. The congestion level of the target congested section largely depends on whether the downstream intersections can promptly allow vehicles entering from that section to pass. If the downstream intersections lack sufficient capacity, vehicles will remain stuck within the target congested section, causing queue lengths to continuously increase. Therefore, accurately obtaining the relevant parameters from the current signal timing scheme of the downstream intersections is crucial for quantitatively analyzing the causes of congestion.

[0072] Then, the signal timing scheme currently in operation at the downstream intersection is obtained; the currently operating signal timing scheme can be read from the scheme library of the traffic signal control system. The currently operating signal timing scheme includes parameters such as cycle duration, green light duration, yellow light duration, red light clearing duration, number of lanes in each direction, saturated headway for each lane, phase release sequence, minimum green light constraint duration, and maximum green light constraint duration.

[0073] The cycle duration refers to the total time required for a traffic light to complete one full cycle, including the green, yellow, and red light times for all control phases, measured in seconds. The cycle duration determines the overall traffic flow rhythm at the intersection; a shorter cycle results in shorter waiting times but a larger proportion of lost time, while a longer cycle improves traffic efficiency but increases delays.

[0074] The control phase refers to the signal light display status corresponding to a set of non-conflicting traffic flows that can synchronously obtain the right of way within a complete signal cycle. Within the same signal cycle, each control phase rotates in turn according to a preset time sequence. At any given time, only the traffic flow of the current control phase is allowed to pass, while other traffic flows must wait. The control phase is configured with an independent phase duration, which includes the green light duration, yellow light duration, and all-red clearing duration. The green light duration is a key parameter for calculating the entry and exit capacity of the intersection and is also a core variable for subsequent timing adjustments. The yellow light and all-red clearing durations are fixed safety thresholds and are not involved in green light control modifications.

[0075] For example, if the target congested road segment is in the east-west direction, and vehicles need to go straight through the downstream intersection after entering from that road segment, then the east-west straight-through phase of the downstream intersection is the control phase corresponding to that outgoing direction.

[0076] The saturated headway refers to the average time interval between two consecutive vehicles passing through the same cross section, such as a stop line, under saturated traffic conditions, measured in seconds per vehicle. The smaller the saturated headway, the more vehicles pass through per unit time, and the greater the traffic capacity.

[0077] In some embodiments, the saturation headway is obtained by first determining the lane function division, i.e., the lane type, corresponding to the outbound direction of the target congested road segment. For example, the direction from the target congested road segment to the downstream intersection may include straight lanes, left-turn lanes, right-turn lanes, or combined lanes (such as left-turn and straight lanes). Different lane types have different saturation headways.

[0078] Then, the corresponding saturation headway is obtained by looking up the table according to the lane type; the saturation headway is obtained through the following Table 3: Table 3

[0079] The above values ​​are empirical values, obtained based on statistics of typical urban road conditions. In practical applications, they can be calibrated and corrected based on measured intersection data from various cities. For example, for road sections with a high proportion of large vehicles, the headway should be appropriately increased; for areas with relatively smooth driving, the headway can be appropriately decreased.

[0080] The number of lanes refers to the number of lanes in the outbound direction of the target congested road segment corresponding to the control phase. For example, if the westbound direction of the target congested road segment towards intersection B includes 2 straight lanes and 1 left-turn lane, then the control phase for the straight direction corresponds to 2 lanes, and the control phase for the left-turn direction corresponds to 1 lane.

[0081] S322. Calculate the exit capacity based on the ratio of the green light duration to the cycle duration, the saturation headway, and the number of lanes.

[0082] Furthermore, the specific implementation method for calculating the exit capacity based on the ratio of the green light duration to the cycle duration, the saturation headway, and the number of lanes can be calculated using the following formula:

[0083] in, The outbound traffic capacity (unit: vehicles / hour) can be converted to vehicles / preset statistical time. For example, the preset unit time is 5 minutes, and the coefficient 300 is obtained by converting 3600 / 12. This is because 1 hour = 3600 seconds and 5 minutes = 300 seconds. Since 5 minutes is used as the preset statistical unit, multiplying by 300 completes the scale conversion, which is convenient for calculating the difference with the upstream inbound traffic capacity. This represents the total signal cycle duration of the current signal timing scheme at the downstream intersection; n is the total number of lanes corresponding to the outgoing direction. This represents the green light duration for the control phase corresponding to the i-th straight lane, and the time during which straight traffic is granted the right of way during that phase. This represents the green light duration for the control phase corresponding to the i-th left-turn lane, and the time during which left-turning traffic is granted the right of way during that phase. denoted as the saturated headway for the i-th straight lane, which is the average time interval between two consecutive straight-going vehicles passing through the cross section under saturated flow conditions. It represents the saturated headway corresponding to the i-th left-turn lane, which is the average time interval between two consecutive left-turning vehicles passing through the section under saturated flow conditions.

[0084] Then, the exit traffic flow at the downstream intersection under the current signal timing scheme is calculated according to the above formula. It should be noted that when there is only one control phase, vehicles exiting the target congested section are only allowed to pass through a single phase. That is, the straight lane and left-turn lane corresponding to that direction simultaneously obtain the right-of-way in the same phase. For example, in a combined east-west straight and left-turn phase, the straight lane and left-turn lane share the same green light duration. The saturation headway is substituted into each lane and summed for calculation. If the exit direction only contains a single lane type (only a straight lane or only a left-turn lane), only the capacity term for the corresponding lane type needs to be calculated, and the other term is set to zero. The formula still applies.

[0085] S323. For the upstream intersection, obtain the cycle duration under the current intersection signal timing scheme, the green light duration of the control phase corresponding to the direction of entry of the target congested road segment, and the saturation headway and number of lanes of the corresponding lane.

[0086] Specifically, the upstream intersection refers to the starting intersection of the target congested road segment, that is, the previous intersection that vehicles pass before entering the target congested road segment. (Refer to...) Figure 7 The diagram shows a road map of the target congested intersection. The target congested section is the eastbound section 71 from intersection A to intersection B. That is, if a vehicle is traveling from intersection A to intersection B, then the upstream intersection is intersection A.

[0087] It should be noted that the upstream intersection is the source node for vehicles entering the target congested section. The release method and capacity of the upstream intersection directly determine how many vehicles enter the target congested section. When the inbound capacity of the upstream intersection is too large, it can easily lead to vehicle backlog in the target congested section; when the inbound capacity is too small, although it helps to alleviate the pressure on the target congested section, it may create new queues at the upstream intersection.

[0088] Then, obtain the signal timing scheme currently in operation at the downstream intersection; referring to the description of S321 above, the signal timing scheme currently in operation can be read from the scheme library of the traffic signal control system, which also includes parameters such as cycle duration, green light duration for each phase, yellow light duration, all-red light duration, phase sequence, and the barrier to which the phase belongs.

[0089] Unlike S321, this step requires obtaining the green light duration of the control phase corresponding to the direction of entry into the target congested road segment.

[0090] Specifically, the control phase corresponding to the direction of entry refers to the phase in which traffic flowing from the upstream intersection toward the target congested road segment is granted the right of way. For example, if the target congested road segment is an eastbound segment from intersection A to intersection B, and vehicles exit from intersection A and enter this segment, then the east-west straight-ahead phase (i.e., the west-west straight-ahead direction) at intersection A is the control phase corresponding to this direction of entry. Vehicles are granted the right of way during the green light period of this phase and can exit from the upstream intersection and enter the target congested road segment.

[0091] Therefore, the cycle duration, saturation headway, and number of lanes under the current intersection signal timing scheme can all be obtained using the same method as in S321, simply by replacing the downstream intersection with the upstream intersection from this step; the acquisition method is the same and will not be repeated here. Based on the obtained parameters, the entry capacity of the upstream intersection under the current intersection signal timing scheme can be obtained using the same calculation formula as in S322. For the specific calculation method, please refer to the relevant explanation in S322, which will not be repeated here.

[0092] S324. Calculate the entry capacity based on the ratio of the green light duration to the cycle duration, the saturation headway, and the number of lanes.

[0093] Furthermore, the specific implementation method for calculating the entry capacity based on the ratio of the green light duration to the cycle duration, the saturation headway, and the number of lanes can be calculated using the following formula:

[0094] in, The inbound traffic capacity (unit: vehicles / hour) can be converted to vehicles / preset statistical duration; C represents the total signal cycle duration of the current signal timing scheme of the upstream intersection, in seconds; n is the total number of lanes corresponding to the outbound direction; This represents the green light duration for the control phase corresponding to the i-th straight lane, and the time during which straight traffic is granted the right of way during that phase. This represents the green light duration for the control phase corresponding to the i-th left-turn lane, and the time during which left-turning traffic is granted the right of way during that phase. denoted as the saturated headway for the i-th straight lane, which is the average time interval between two consecutive straight-going vehicles passing through the cross section under saturated flow conditions. It represents the saturated headway corresponding to the i-th left-turn lane, which is the average time interval between two consecutive left-turning vehicles passing through the section under saturated flow conditions.

[0095] It should be noted that the calculation methods for outbound and inbound traffic capacity in S321 to S324 are completely symmetrical, based on the same calculation formula. The only difference is that the calculation objects are downstream intersections and upstream intersections, and the corresponding control phases are different.

[0096] Based on the above S321-S324, the cycle, green light duration, number of lanes, and saturation headway of the corresponding release phases at upstream and downstream intersections are collected respectively. Based on the green light duty cycle, lane size, and saturation release interval, the entry and exit capacity is quantified. It can distinguish different release conditions at both ends of the road segment and accurately calculate the upper limit of traffic flow capacity, taking into account the differentiated traffic characteristics of mixed large and small traffic flows. It objectively quantifies the difference between supply and demand traffic flow in the road segment, avoids the distortion of assessment by a single traffic flow indicator, and provides reliable and standardized numerical basis for determining the cause of congestion and adaptive matching of interception or release control strategies, thereby improving the accuracy of signal control strategy matching.

[0097] S33. The difference between the inbound traffic capacity and the outbound traffic capacity is calculated to obtain the traffic capacity difference of the target congested road segment.

[0098] In this step, the entry capacity calculated in S32 can be used. With exit capacity Perform the difference operation: The traffic capacity difference of the target congested road segment is obtained. ; This is the core quantitative feature of the present invention, used to characterize the degree of matching between the upstream and downstream traffic capacity of the target congested road segment, and is the core basis for judging the cause of congestion and making control strategies.

[0099] when When Q>0, it indicates that the inbound traffic capacity of the upstream intersection is greater than the outbound traffic capacity of the downstream intersection, meaning that the upstream input capacity exceeds the downstream absorption capacity. In this case, the root cause of congestion on the target congested road segment is that the upstream input is too large, exceeding the absorption capacity of the downstream intersection, and vehicles cannot leave the road segment in time, resulting in queues and backlogs.

[0100] when When Q=0, it indicates that the inbound traffic capacity equals the outbound traffic capacity, and the upstream and downstream traffic capacities are in a critical equilibrium state. At this time, any slight fluctuation in traffic demand or random disturbance may lead to congestion.

[0101] when When Q < 0, it indicates that the inbound traffic capacity of the upstream intersection is less than the outbound traffic capacity of the downstream intersection, meaning that the downstream intersection has the capacity to handle upstream traffic in terms of signal timing. However, if congestion still occurs, it means that the current traffic demand has exceeded the capacity limit, and the downstream intersection has become a bottleneck node for traffic flow.

[0102] S34. Determine the target control method for the target congested road segment based on the traffic capacity difference and the road segment status.

[0103] The target control method is: upstream intersection traffic interception control and / or downstream intersection traffic release control.

[0104] Specifically, upstream intersection traffic control refers to reducing the number of vehicles entering the target congested road segment per unit time by shortening the green light duration of the control phase at upstream intersections leading to that segment. The essence of this control method is to reduce input and alleviate pressure; that is, by reducing the release rate from upstream intersections to the congested segment, the traffic flow entering the congested segment is reduced, creating conditions for the dissipation of existing queues within the segment.

[0105] Downstream intersection release control refers to increasing the number of vehicles leaving the target congested road segment per unit time by extending the green light duration of the control phase for outbound directions at downstream intersections. The essence of this control method is to increase output and accelerate dissipation; that is, by increasing the release rate of vehicles from the congested road segment at downstream intersections, the discharge capacity of the congested road segment is increased, thus accelerating the evacuation of queuing vehicles.

[0106] The combination of traffic diversion control and release control refers to implementing traffic diversion control at upstream intersections while simultaneously implementing release control at downstream intersections, achieving coordinated intervention by intercepting traffic upstream and releasing it downstream. This combined approach is suitable for scenarios with the most severe congestion, requiring a simultaneous reduction in traffic input and an increase in traffic output to dissipate congestion as quickly as possible.

[0107] Furthermore, based on the aforementioned traffic capacity differences and road segment conditions, the target control method is further determined; specifically, it includes the following situations: If the difference in traffic capacity is less than or equal to zero, then the upstream intersection interception method will be used for control.

[0108] Specifically, when When Q≤0, it indicates that the upstream inflow capacity is greater than or equal to the downstream outflow capacity, meaning the upstream input capacity is greater than or equal to the downstream absorption capacity. In this case, the congestion is caused by a capacity mismatch not influenced by signal control factors, possibly due to abnormal events or interference leading to a decrease in capacity. Upstream intersection traffic control is employed, and all upstream intersections flowing into this congested section are considered controlled flows.

[0109] If the difference in traffic capacity is greater than zero and the road segment is in a congested state, then it is determined that the downstream intersection addition method will be used for control.

[0110] Specifically, when When Q>0 and the road segment is congested, it indicates that the upstream inbound traffic capacity is less than the downstream outbound traffic capacity. In other words, the downstream intersection has the capacity to handle upstream inbound vehicles at the signal timing level. However, due to the congestion caused by the increase in traffic flow, the downstream intersection is the main traffic bottleneck. The downstream intersection is used for control by adding traffic flow. The outbound direction of vehicles in this congested road segment is the controlled flow direction.

[0111] If the traffic capacity difference is greater than zero and the road segment is in a state of severe congestion, then it is determined that the downstream intersection traffic control and the upstream intersection traffic interception control will be implemented in parallel.

[0112] Specifically, when When Q>0 and the road segment is in a state of severe congestion, it indicates that the upstream inbound traffic capacity is much less than the downstream outbound traffic capacity. The downstream intersection has sufficient capacity space but the congestion is extremely severe, indicating that the rapid increase in traffic flow has led to an excessive mismatch in traffic capacity. While using the downstream intersection to increase capacity for control, it is also necessary to coordinate with the upstream intersection to control traffic flow.

[0113] Furthermore, after determining the target control method, the specific control flow direction also needs to be determined. For upstream intersection traffic control, all inbound directions from upstream intersections pointing to the target congested road segment are determined as the control flow direction; for downstream intersection release control, all outbound directions from downstream intersections exiting the target congested road segment are determined as the control flow direction. When consecutive congested road segments cause the same flow direction to be both the target of traffic control and the target of release control, no timing adjustment is made for that flow direction to avoid control command conflicts.

[0114] S35. Based on the target control method and the traffic volume to be dissipated in the target congested road segment, generate and execute the intersection signal timing adjustment scheme corresponding to the target congested road segment.

[0115] The traffic volume to be dissipated is represented as the total number of vehicles queuing on the target congested road section that are reduced through control measures within the preset unit time.

[0116] Specifically, the traffic volume to be dissipated is the total number of vehicles that are expected to be reduced in the target congested road segment through active intervention of signal timing within the preset unit time, such as 5 minutes. The unit is: vehicles / preset unit time; that is, the traffic volume to be dissipated is how many fewer vehicles are expected to be queued on the road segment within this 5-minute period.

[0117] Furthermore, after determining the traffic volume to be dissipated, corresponding signal timing adjustment schemes are generated based on the different target control methods determined in S34: If the target control method is upstream intersection traffic control, then the green light duration of the control phase pointing to the target congested road segment needs to be shortened at the upstream intersection. The goal of the shortening is that the reduction in traffic volume caused by the green light shortening is equal to the traffic volume to be dissipated, thereby reducing the number of vehicles entering the congested road segment. Green light shortening must meet the minimum green light constraint for the phase to ensure safe passage time for pedestrians and non-motorized vehicles. In terms of calculation mode, depending on whether there is a need for coordinated control at the upstream intersection, either a constant cycle mode (allocating the shortened time to other phases within the same cycle) or a variable cycle mode (allowing the signal cycle to shorten as the green light shortens) can be selected.

[0118] If the target control method involves adding control at downstream intersections, then the green light duration of the control phase in the outgoing direction of the target congested road segment must be extended at the downstream intersection. The goal of this extension is to ensure that the increase in traffic volume due to the extended green light equals the traffic volume to be dissipated, thereby increasing the number of vehicles leaving the congested road segment. The extended green light must satisfy the maximum green light constraint for the phase to prevent excessive waiting times for vehicles in other directions. Similarly, depending on whether there is a need for coordinated control at the downstream intersection, a constant cycle mode (borrowing time from other phases) or a variable cycle mode (allowing the signal cycle to increase with the extension of the green light) can be selected.

[0119] If the target control method is a combination of traffic diversion control and release control, then the traffic volume to be dissipated needs to be allocated to both traffic diversion control and release control. Specifically, real-time traffic flow in the diversion direction and release direction within the most recent preset time period can be obtained, and the total control volume can be allocated according to the traffic flow ratio of the two. After obtaining the allocated control volume, the upstream diversion scheme and downstream release scheme are independently calculated according to the above-mentioned methods for traffic diversion control and release control, respectively, to achieve upstream and downstream coordination and two-way intervention.

[0120] Furthermore, based on the different intersection signal timing adjustment schemes mentioned above, the control range of primary intersections is verified. When the control volume required for a primary intersection is large, to avoid excessive control at a single point, causing prolonged traffic congestion at upstream intersections and inducing new secondary congestion, the portion of the control load exceeding the upper limit of the primary intersection's control capacity will be distributed to upstream secondary, tertiary, and even n-level remote control intersections. Specifically, the maximum compressible threshold for the green light phase at the primary intersection needs to be determined first to obtain the maximum traffic flow reduction that the intersection can bear within its safe range. Then, the remaining unbearable control margin is proportionally allocated based on the real-time traffic flow and adjustable green light margin at each level of upstream remote intersections. The green light compression duration corresponding to each level of upstream intersection is calculated one by one to build a hierarchical upstream traffic interception control scheme. By relying on a collaborative model of primary traffic control at near-end primary intersections and secondary traffic diversion at far-end multi-level intersections, the pressure of single-point intersection control is dispersed, and the problem of upstream traffic overflow caused by excessive compression of green lights at primary intersections is eliminated. On the basis of ensuring the quality completion of the goal of dispersing queuing vehicles on the road section, the traffic pressure of the entire upstream passage is balanced, ensuring the stability of traffic in the entire road network.

[0121] This application embodiment obtains the target congested road segment and its status, calculates the outbound capacity of the downstream intersection and the inbound capacity of the upstream intersection corresponding to the target congested road segment under the current timing scheme, and then calculates the capacity difference by subtracting the inbound capacity from the outbound capacity. Based on the capacity difference and the road segment status, it determines the upstream intersection traffic control and / or the downstream intersection traffic control as the target control method. Finally, based on the target control method and the traffic volume to be dissipated, it automatically generates and executes the target intersection signal timing scheme. The entire process does not require manual intervention, avoiding the problems of reliance on human experience and response lag. At the same time, since the calculation of the capacity difference and the selection of the control method do not depend on preset specific intersections or areas, but are dynamically adapted according to the real-time road segment status and the capacity difference, it can cover any road segment in the road network that is congested, breaking through the limitations of preset objects and significantly improving the efficiency and scenario adaptability of traffic signal control.

[0122] It should be noted that before implementing S35, the corresponding traffic volume to be dispersed needs to be determined. Specifically, the traffic volume to be dispersed can be obtained using the following steps 1 and 2: Step 1: Obtain the congestion length and number of lanes of the target congested road segment.

[0123] The congestion length refers to the actual distance the queue of vehicles extends along the target congested road segment, which can be obtained through real-time traffic data provided by map providers, roadside radar detection, or video image recognition. The number of lanes refers to the number of approach lanes included in the congested road segment, which can be read from a static road network attribute database.

[0124] The two parameters mentioned above together determine the total number of vehicles currently queuing in the congested section: the total number of vehicles in the queue is approximately equal to (congestion length / average space occupied by a single vehicle) × number of lanes, where the average space occupied by a single vehicle is an empirically calibrated value, for example, 7 meters.

[0125] Step 2: Calculate the traffic volume to be dissipated based on the congestion length, the number of lanes, and the congestion dissipation rate per unit time.

[0126] The congestion reduction rate is used to characterize the proportion of the queue length to the current congestion length that is expected to be eliminated within a preset unit time, such as 5 minutes. This value can be set by default by the system, such as 0.3, which means that 30% of the current congestion length is expected to be eliminated. It can also be manually configured by traffic management personnel according to actual control needs.

[0127] Based on the above parameters, the formula for calculating the traffic volume to be dissipated is:

[0128] in, Traffic volume to be dissipated, in vehicles per preset unit time; Due to poor traffic capacity, The number of vehicles entering from upstream is greater than the number of vehicles leaving from downstream per unit of time, resulting in continuous traffic congestion on the road section. This means that the downstream traffic flow can fully accommodate the upstream inflow, and only the existing queues need to be cleared.

[0129] The congestion reduction range is 0 to 1, for example, 0.3, which represents the proportion of the planned queue length to be eliminated per unit time to the current total congestion length; L is the current measured queue length of the target congested road segment; n is the total number of lanes for vehicles traveling in the same direction on the congested road segment; l is the average road length occupied by a single vehicle in queue, which is a system preset calibration constant. For rounding operations, the calculated decimal traffic flow value is converted into an integer number of vehicles to match the actual traffic flow unit under control.

[0130] Furthermore, when At that time, that is, through The traffic volume to be dissipated is calculated when the upstream inbound capacity exceeds the downstream outbound capacity, and the congestion is caused by the traffic backlog due to the capacity difference. Therefore, the traffic volume to be dissipated includes not only the queue length expected to be actively dissipated (basic dissipation volume δ×L×n / l), but also the excess traffic volume corresponding to the capacity difference. This aims to eliminate the incremental sources that exacerbate congestion; that is, the above formula can be understood as: Total control demand = Elimination of accumulated excess traffic volume + Active dissipation of target queue volume; and then eliminating congestion through traffic diversion. At the same time, the δ-proportion dissipation is gradually achieved by adding or diverting water, thereby achieving two-way relief of congestion.

[0131] when At that time, that is, through When calculating the traffic volume to be dispersed, the upstream inbound capacity is no greater than the downstream outbound capacity, meaning there is no inherent capacity bottleneck at the signal control level. Congestion is most likely caused by non-signal control factors (such as traffic accidents, vehicle violations, and road construction), and there is no accumulated excess traffic volume to be eliminated. Therefore, the traffic volume to be dispersed only includes the queue length expected to be actively dispersed, and does not need to be superimposed. The above formula can be understood as follows: In scenarios where congestion is not caused by signal factors, the control objective is only to create a time window for the dissipation of abnormal events through traffic diversion (reducing upstream vehicles), rather than solving the problem of capacity mismatch. Therefore, the control quantity is determined only based on the expected queue length to dissipate, and does not involve compensation for capacity discrepancies.

[0132] Based on steps 1 and 2 above, the amount of traffic to be dispersed is dynamically quantified by combining real-time congestion queue length, lane size, and control dissipation ratio. Differentiated control targets are calculated for two scenarios: congestion aggravation and existing backlog. At the same time, it supports managers to adjust the dissipation range as needed to adapt to different control intensities during peak and off-peak hours. By rounding to the nearest whole number to match the actual vehicle counting rules, it provides a precise and quantifiable control benchmark for subsequent upstream traffic interception and downstream traffic timing adjustments, avoiding the problems of insufficient or excessive control caused by relying on experience-based estimations for timing adjustments.

[0133] As an extension and refinement of the above embodiments, refer to Figure 8 As shown, S35 in the above embodiment can be further refined into S81-S84 as follows: S81. Determine the control intersection and the corresponding control flow direction according to the target control method.

[0134] Depending on the target control method, the methods for determining the control intersection and the corresponding control flow direction include the following: When the target control method is upstream intersection traffic control, the controlled intersection is the upstream intersection of the target congested road segment, and the controlled flow direction is the direction of travel entering the target congested road segment, that is, the direction of travel from the upstream intersection to the entrance lane of the road segment. In this scenario, the control objective is to reduce the traffic volume entering the target congested road segment from the upstream intersection. By implementing green light compression for the corresponding flow direction at the upstream intersection, the entry capacity is reduced, thereby alleviating the queuing pressure on the target congested road segment.

[0135] When the target control method is to add control at a downstream intersection, the controlled intersection is the downstream intersection of the target congested road segment, and the controlled flow direction is the direction of exiting the target congested road segment, that is, the direction of entering the downstream intersection and continuing to travel after exiting the target congested road segment. In this scenario, the control objective is to improve the dispersal capacity of the downstream intersection for vehicles exiting the target congested road segment. By increasing the green light for the corresponding flow direction at the downstream intersection, the exit capacity is improved, thereby accelerating the dissipation of queued vehicles in the target congested road segment.

[0136] When the target control method is upstream-downstream coordinated control, the controlled intersections include both the upstream and downstream intersections of the target congested road segment; the control flow direction is the direction of entering the target congested road segment at the upstream intersection and the direction of exiting the target congested road segment at the downstream intersection. In this scenario, the control objective is to exert force simultaneously from two directions—"reducing input" and "increasing output"—to form a two-way coordinated effect and quickly eliminate severe congestion.

[0137] It should be noted that in scenarios involving consecutive congested road segments, where multiple congested segments are connected end-to-end, a certain common intersection may simultaneously serve a dual role. This intersection acts as both a downstream access point for the preceding congested segment and an upstream interception point for the following congested segment. If the same flow direction within this intersection is simultaneously identified as both an upstream interception control target and a downstream access control target, it indicates that simultaneously implementing green light reduction and green light extension for that flow direction would create a direct contradiction and cannot be implemented concurrently.

[0138] In the above situation, this flow direction will not be considered a control flow direction and no timing adjustments will be made to avoid control command conflicts that could lead to signal scheme logic errors or intersection operational disorder. The control requirements corresponding to this flow direction will be ignored or compensated for by other adjacent control flows.

[0139] Reference Figure 9 The diagram shows a road layout for a scenario with continuous traffic congestion. It exemplarily illustrates three consecutive intersections (intersection A, intersection B, and intersection C) and two consecutive congested road segments in between. Intersection A is upstream of the first congested road segment 91, intersection B is downstream of the first congested road segment 91 and simultaneously upstream of the second congested road segment 92, and intersection C is downstream of the second congested road segment 92. Solid and dashed arrows indicate the control methods for each intersection, with solid arrows representing the addition of traffic and dashed arrows representing the traffic diversion method.

[0140] For continuously congested road segments, the aforementioned steps must be performed separately for each congested segment to determine its corresponding control intersection, control flow direction, and control method. Any control command conflicts that may arise at common intersections should be merged according to the following rules: If the flow direction at a certain intersection is simultaneously identified as the downstream addition flow direction of the previous congested segment and the upstream interception flow direction of the subsequent congested segment (e.g., Figure 9 For the westbound direction at intersection B in the middle of the road, there is a control mode conflict. In this case, the flow direction is determined as a non-controlled flow direction that does not require timing adjustment, and the aforementioned green light adjustment calculation step is not performed. For the other intersection flows that do not have conflicts, the aforementioned steps are performed according to their respective control modes to calculate their green light adjustment amounts and finally generate the target signal timing scheme for each intersection.

[0141] by Figure 9 Taking this scenario as an example, the control requirements for two consecutive congested road sections are as follows: The first congested section, number 91, is located between intersection A and intersection B. Based on the assessment of traffic capacity and road condition, the control method is coordinated upstream and downstream control. Specifically, traffic entering from upstream intersection A, including the westward straight-through direction and the northward left-turn direction, will be subject to traffic diversion control to reduce the amount of traffic entering this section. Traffic exiting from downstream intersection B, including the westward left-turn direction, will be subject to additional traffic flow control to improve the vehicle dispersal capacity of this section.

[0142] The second congested section, number 92, is located between intersections B and C. Based on the assessment of poor traffic capacity and the current condition of the section, its control method is also coordinated upstream and downstream control. Specifically, traffic entering from upstream intersection B, including the northbound left turn direction, needs to be controlled to reduce the amount of traffic entering this section; traffic exiting from downstream intersection C, including the westbound straight-through direction and the westbound left turn direction, needs to be controlled to improve the vehicle dispersal capacity of this section.

[0143] Therefore, in the control requirements of the two consecutive congested road segments mentioned above, intersection B simultaneously assumes two roles: it serves as a downstream access point for adding green lights in the first congested road segment and an upstream interception point in the second congested road segment. For the north-left turn direction at intersection B, the control requirement is for adding green lights in the first congested road segment and for interception in the second congested road segment. The simultaneous requirement for adding green lights (increasing green light duration) and interception (reducing green light duration) for the same flow direction at the same intersection constitutes a direct control conflict.

[0144] When the same flow direction at a public intersection within a congested road segment is simultaneously identified as both an upstream interception target and a downstream addition target, that flow direction is not considered a control flow direction and no timing adjustments are made. Therefore, the north-left turn direction at intersection B is excluded and not included in the final control plan.

[0145] The final effective control plan is as follows: Intersection A: Traffic control will be implemented for the westward straight direction and the northward left turn direction; Intersection B: Traffic control will be implemented for the westward left turn direction (the northward left turn direction is excluded due to conflict and will not be adjusted); Intersection C: Traffic control will be implemented for the westward straight direction and the westward left turn direction.

[0146] Each congested road segment has a clear and definite control intersection, control flow direction, and control method, and avoids command conflicts in multi-segment collaborative control scenarios, ensuring the feasibility of the signal timing adjustment scheme and the safety of intersection operation.

[0147] S82. Based on the current intersection signal timing scheme of the controlled intersection, determine the control phase corresponding to the control flow direction and the green light duration, cycle duration, number of lanes and headway of the control phase in the current timing scheme.

[0148] This step extracts the basic parameters necessary for subsequent calculations from the current signal timing scheme of the controlled intersection, and uses them as input data for calculating the green light adjustment.

[0149] Specifically, after determining the controlled intersection and its corresponding traffic flow direction, the first step is to obtain the signal timing scheme currently in effect at that intersection. From this scheme, the following information can be retrieved: one or more control phases corresponding to the traffic flow direction, the green light duration for each control phase in the current timing scheme, the total signal cycle duration at the intersection, and the number of lanes corresponding to the traffic flow direction for each control phase. Additionally, the saturated headway for each lane needs to be obtained. This parameter can be read from a preset headway lookup table based on the lane type. Different lane types (such as dedicated left-turn lanes, straight-ahead lanes, and shared left-turn / straight-ahead lanes) have different saturated headways.

[0150] The parameters mentioned above form the baseline data for calculating green light adjustments. Green light duration and cycle length determine the baseline level of current traffic capacity, while the number of lanes and saturation headway reflect the traffic efficiency characteristics of that flow direction. Timing schemes may differ at different intersections; for example, the same controlled flow direction may correspond to a single control phase or multiple control phases.

[0151] S83. Calculate the green light adjustment amount of the control phase based on the traffic volume to be dissipated, the green light duration, the cycle duration, the number of lanes, and the headway.

[0152] Then, after obtaining the parameters of the current timing scheme, this step calculates the specific values ​​that the green light time of each control phase needs to be adjusted based on the traffic volume to be dissipated.

[0153] Traffic volume to be dispersed is represented by the total number of vehicles queuing on congested road sections that need to be reduced through traffic control within a preset unit of time. To achieve this number of vehicle dissipation within a unit of time, the capacity of the controlled flow direction needs to be adjusted accordingly. This capacity adjustment is achieved by changing the green light duration of the control phase. Specifically, for upstream intersection traffic control, the green light duration of the control phase needs to be shortened to reduce the number of vehicles entering the congested road section within a unit of time; for downstream intersection traffic control, the green light duration of the control phase needs to be extended to increase the number of vehicles exiting the congested road section within a unit of time.

[0154] When calculating the green light adjustment, firstly, based on the green light duration, corresponding number of lanes, and saturated headway of each control phase in the current timing scheme, the existing capacity of each control phase per unit time is calculated. Then, based on the traffic volume to be dissipated, the increased or decreased traffic volume to be handled by each control phase is allocated according to the proportion of its capacity. Finally, based on the allocated traffic changes for each phase, along with their corresponding number of lanes and saturated headway, the required extended or shortened green light duration for each control phase is calculated.

[0155] It should be noted that if multiple control phases correspond to the same control flow direction, these phases share the traffic volume to be dissipated according to their respective capacity ratios. The green light adjustment amount for each phase is positively correlated with its existing capacity; that is, the phase with the greater capacity bears more adjustment. Simultaneously, the coordination requirements of the timing scheme must be considered during the calculation. If signal coordination between intersections is required, the adjusted cycle length should be consistent with the coordination benchmark; if coordination is not required, the cycle length is allowed to vary accordingly based on the green light adjustment amount. Regardless of the method used, the adjusted green light duration for each phase must not be less than the minimum green light duration for the corresponding phase to ensure basic safety needs such as pedestrian crossings are guaranteed.

[0156] S84. Adjust the current intersection signal timing scheme according to the green light adjustment amount, generate the target intersection signal timing scheme and execute it.

[0157] After calculating the green light adjustment for each control phase, this step applies the adjustment to the current timing scheme, generates a new intersection signal timing scheme, and issues it for execution.

[0158] Specifically, the green light compression or extension amount calculated in step S83 for each control phase is applied to the green light duration of the corresponding phase in the current timing scheme to obtain the adjusted green light duration for each phase. Based on this, the total signal cycle duration of the intersection is re-determined according to the adjustment results of each phase. That is, if the change in the green light duration of each phase causes a change in the cycle duration, the cycle parameters are updated accordingly, and the green light duration allocation of non-control phases is reasonably adjusted to ensure that the sum of the durations of each phase within the cycle matches the new total cycle duration.

[0159] After the new timing scheme is generated, its validity needs to be verified, including: whether the green light duration of each phase meets the minimum green light constraint, whether the cycle length is within a reasonable range, and whether the logical relationship between each phase (such as barrier settings) has been disrupted. If the verification passes, the new timing scheme is sent to the traffic signal controller at the intersection for execution, realizing automatic adjustment of the intersection signal timing. If the verification fails, the scheme needs to be modified or recalculated while meeting the constraints.

[0160] Furthermore, the calculation process of S83 (calculating the green light adjustment amount of the control phase based on the traffic volume to be dissipated, the green light duration, the cycle duration, the number of lanes, and the headway) may include the following: Scenario 1: When the control method is upstream intersection traffic control, the calculation of the green light adjustment amount for the control phase based on the traffic volume to be dissipated, the green light duration, the cycle duration, the number of lanes, and the headway includes: The green light duration after the control phase compression is determined based on the green light duration, corresponding number of lanes, saturation headway, cycle duration of the control phase in the current timing scheme, and the traffic volume to be dissipated.

[0161] The compressed green light duration of the control phase satisfies the constraint that it is not less than the minimum green light duration of the corresponding phase.

[0162] In this step, the green light duration after control phase compression is determined based on the green light duration, corresponding lane number, saturation headway, and cycle length of the control phase in the current timing scheme, as well as the traffic volume to be dissipated. The compressed green light duration is the calculated result of the green light adjustment.

[0163] It should be noted that the specific calculation method for the green light adjustment amount in this step varies depending on the actual scenario; such as whether the number of controlled phases is one or two, whether the timing scheme keeps the cycle unchanged or allows the cycle to change during the adjustment process, and whether the controlled intersection is a single-level controlled intersection or a multi-level controlled intersection.

[0164] Therefore, before calculating the green light adjustment, it is first necessary to determine whether the current intersection's timing scheme maintains a constant cycle length during the adjustment process. This is because the cycle length in the signal timing scheme often carries the coordination and control function of the intersection. Multiple intersections along urban arterial roads typically operate with the same signal cycle to achieve green wave control. If the cycle length of an intersection involved in coordination changes during the adjustment, it will disrupt the phase difference relationship between that intersection and other intersections, leading to coordination failure. Therefore, it is necessary to choose a calculation method with a constant cycle, i.e., redistributing the time difference generated by the green light adjustment within the cycle, or a calculation method with a variable cycle, i.e., allowing the cycle to expand or contract accordingly with the green light adjustment, depending on whether there is a coordination requirement at the intersection.

[0165] Secondly, it is necessary to determine whether the intersection to be calculated is a primary control intersection or a multi-level control intersection. For traffic diversion control, the primary control intersection is the first intersection directly adjacent to the upstream of the target congested road segment; for traffic release control, the primary control intersection is the first intersection directly adjacent to the downstream of the target congested road segment. If the intersection to be calculated is a primary control intersection, the traffic volume to be dissipated is directly calculated using the Q value obtained in step S82; if the intersection to be calculated is a multi-level control intersection, i.e., a subsequent intersection traced upstream or downstream due to the queue length increase exceeding the limit caused by the primary intersection scheme, the traffic volume to be dissipated is the control volume that the current intersection needs to bear after being allocated by the previous level intersection. The specific allocation method will be explained in the multi-level control section later.

[0166] Furthermore, explanations are provided for different scenarios, such as controlling one or two phases, maintaining a constant cycle or allowing cycle changes during timing adjustments, and controlling intersections as either single-level or multi-level control intersections: (1) When the control flow direction corresponds to a control phase, and the timing scheme maintains a constant period during the adjustment process, the scheme calculation for the upstream level control intersection is as follows: Let the current green light duration for this phase be... The current cycle duration is The corresponding number of lanes is m, and the saturation headway for each lane is... The traffic volume to be dissipated is Q, and the shortened green light duration is... .

[0167] Specifically, the capacity of this phase before compression is the ratio of green light duration to cycle duration multiplied by the sum of the saturation flow rates of each lane, that is: Capacity before compression = After compression, the green light duration is reduced from... shortened to The traffic capacity then becomes: Compressed traffic capacity = Since the period remains unchanged (still is) The difference in traffic capacity before and after compression is: Traffic capacity difference = .

[0168] This capacity difference represents the number of vehicles reduced per second. To align with the dimensions of the traffic volume Q to be dissipated, it needs to be converted to the cumulative number of vehicles reduced over 5 minutes (300 seconds). Therefore, multiplying by 300 leads to the following equation:

[0169] The compressed green light duration can be obtained from this equation. :

[0170] In the above formula, This represents the number of vehicles that need to be reduced per second, multiplied by the cycle length. The total number of vehicles that need to be reduced within a period is obtained, and then divided by the sum of the saturation flow rates of each lane. This will give you the number of green light seconds that need to be compressed.

[0171] The compressed green light duration g must also satisfy the following constraints:

[0172] This constraint sets upper and lower limits for green light compression. The lower limit is... and The larger of the two, i.e., the compressed green light duration, cannot be less than the minimum green light duration of the phase. Meanwhile, each compression should not exceed 5 seconds or 30% of the current green light duration (whichever is greater) to avoid drastic changes in timing schemes impacting traffic flow. The upper limit is [not specified]. and The larger of the two values ​​should be used to ensure a compression time of at least 3 seconds to guarantee the adjustment has a practical effect. If the calculated value of g exceeds the constraint range, the corresponding boundary value should be taken as the final result.

[0173] (2) When the control flow corresponds to two control phases, and the timing scheme maintains a constant period during adjustment, the scheme calculation for the upstream level control intersection is as follows: Let the current green light duration for phase 1 be... After compression, it becomes The corresponding number of lanes is n, and the headway of each lane is... Phase 2 current green light duration is After compression, it becomes The corresponding number of lanes is m, and the headway of each lane is... The current cycle duration is The traffic volume to be dissipated is Q.

[0174] In this scenario, the passage capacity of the two phases before compression is as follows: Passage capacity of phase 1 before compression = Phase 2 capacity before compression = After compression, the green light duration for phase 1 becomes g1, and the green light duration for phase 2 becomes g2, but the cycle remains the same. The passage capacity of the two phases remains unchanged after compression, therefore, the passage capacity of phase 1 after compression is as follows: Passage capacity of phase 1 after compression = Phase 2 compression capacity = .

[0175] The sum of the capacity reductions before and after the compression of the two phases should equal the capacity value of the traffic volume Q to be dissipated, converted to a 5-minute unit time. Simultaneously, to maintain the time ratio between the two phases consistent with that before compression—that is, to ensure the original green light duration ratio of the two phases is not changed due to the compression operation—the ratio of the green light durations of the two phases after compression should be equal to the ratio of the green light durations of the two phases before compression. Based on this, the following system of equations is established:

[0176] The first equation in the above set of equations can be understood as the reduction in capacity in phase 1 plus the reduction in capacity in phase 2, which equals the traffic volume to be dissipated converted into the number of vehicles in a single cycle.

[0177] From this system of equations, the expressions for the green light duration after phase compression can be obtained as follows:

[0178]

[0179] In seeking and Afterwards, it is necessary to verify whether the green light duration after the two phase compressions meets the constraints.

[0180] Specifically, the constraints are as follows:

[0181]

[0182] In the above constraints, the compressed green light duration for phase 1 The lower limit is taken and The larger of the two, meaning the compressed green light duration cannot be less than the minimum green light duration for that phase. To ensure basic safety needs such as pedestrian crossings are met; at the same time, the reduction in time should not exceed 5 seconds or 30% of the current green light duration (whichever is greater), to avoid drastic changes in the timing scheme from impacting traffic flow; the upper limit is... and Choose the larger of the two and ensure that the compression time is at least 3 seconds to guarantee that the adjustment is effective.

[0183] Phase 2 compressed green light duration The lower limit is taken and The larger of the two, meaning the compressed green light duration cannot be less than the minimum green light duration for that phase. To ensure basic safety needs such as pedestrian crossings are met; at the same time, the reduction in time should not exceed 5 seconds or 30% of the current green light duration (whichever is greater), to avoid drastic changes in the timing scheme from impacting traffic flow; the upper limit is... and Choose the larger of the two and ensure that the compression time is at least 3 seconds to guarantee that the adjustment is effective.

[0184] If calculated according to the formula or If the green light duration exceeds the corresponding constraint range, the corresponding boundary value is taken as the final result. For example, if the calculated compressed green light duration is less than the lower limit, the lower limit is taken as the final green light duration for that phase; if the calculated compressed green light duration is greater than the upper limit, the upper limit is taken as the final result, and other parameters in the timing scheme are adjusted accordingly to ensure that the green light duration allocation for each phase is reasonable and meets all constraints; the compressed cycle duration remains unchanged. constant.

[0185] (3) When the control flow corresponds to a control phase and periodic variation is allowed, since there is no need for coordination with other intersections, the total signal cycle duration can be shortened by compressing the green light duration of this phase; the scheme calculation for the upstream level control intersection is as follows: Let the current green light duration for this phase be... The current cycle duration is The corresponding number of lanes is m, and the saturation headway for each lane is... Let Q be the traffic volume to be dissipated, and g be the compressed green light duration.

[0186] Since the period is variable, the compressed period duration C becomes: That is, the compressed cycle duration is equal to the original cycle duration minus the green light compression amount for that phase. This is because when the green light for this phase is compressed, the compressed time is no longer allocated to other phases, but is directly deducted from the total cycle duration, thus shortening the overall cycle.

[0187] Substituting the compressed periodic expression above into the case established in case one (1) where the period remains unchanged... In the equation, the fixed period in the denominator is... Replace with variable period The following equation can be obtained:

[0188] The physical meaning of this equation is the same as in the case of constant period: the cumulative reduction in capacity after compression over 5 minutes equals the traffic volume Q to be dissipated. The difference lies in the period in the denominator, which is now fixed. It becomes variable with g. This demonstrates the characteristic that the cycle shortens synchronously with the compression of the green light in the case of a variable cycle.

[0189] Therefore, the compressed green light duration can be obtained from the above equation. :

[0190] After obtaining g, the compressed period This is also determined. The compressed green light duration g must also satisfy the following constraints:

[0191] The meaning of this constraint is the same as the aforementioned case of constant period, that is, the lower limit is taken as... and The larger of the two, i.e., the compressed green light duration, cannot be less than the minimum green light duration of the phase. Meanwhile, each compression should not exceed 5 seconds or 30% of the current green light duration (whichever is greater) to avoid drastic changes in timing schemes impacting traffic flow. The upper limit is [not specified]. and The larger of the two values ​​should be used to ensure a compression time of at least 3 seconds to guarantee the adjustment has a practical effect. If the calculated value of g exceeds the constraint range, the corresponding boundary value should be taken as the final result.

[0192] (4) When the control flow corresponds to two control phases and periodic variation is allowed, since there is no need for coordination with other intersections, the total signal cycle duration can be shortened accordingly after compressing the green light duration of the two phases; the scheme calculation for the upstream level control intersection is as follows: Let the current green light duration for phase 1 be... After compression, it becomes The corresponding number of lanes is n, and the headway of each lane is... Phase 2 current green light duration is After compression, it becomes The corresponding number of lanes is m, and the headway of each lane is... The current cycle duration is The traffic volume to be dissipated is Q.

[0193] In this scenario, the positional relationship between the two control phases in the signal timing scheme directly affects the calculation method of the compressed cycle length. In signal timing, barriers are used to separate traffic flows from different directions at an intersection, such as north-south and east-west, ensuring that traffic flows from different directions are not released at the same time, thus preventing timing conflicts. The positional relationship between the two control phases in the scheme determines their timing operation: when the two control phases are located in the same barrier but in different loops, they operate in parallel time, each occupying one loop's timeline, and the cycle length is dominated by the phase with the longer operating time; when the two control phases do not satisfy the above positional relationship, they operate in series time, and the cycle length is the sum of the two phase durations plus the durations of other fixed phases.

[0194] The two positional relationships will be explained below.

[0195] When two control phases are located in the same barrier but different loops, they run in parallel in time, and the compressed period duration is dominated by the larger of the two compressed period durations.

[0196] If the green light duration before phase 1 compression is relatively long (i.e.) ≥ The compressed period is determined by phase 1, which is equivalent to the original period minus the compression amount of phase 2: If the green light duration before phase 2 compression is relatively long (i.e. < The compressed period is determined by phase 2, which is equivalent to the original period minus the compression amount of phase 1: Furthermore, the above two types Substitute the expressions into the following system of equations:

[0197] Furthermore, when ≥ hour, The expression is:

[0198] when < hour, The expression is:

[0199] In seeking Then, through the system of equations You can get .

[0200] When two control phases do not satisfy the positional relationship of being in the same barrier and different loops, they operate in series in time. The compressed cycle length is the original cycle minus the sum of the green light compression amounts of the two phases: That is, the cycle is shortened accordingly as the green light duration of the two phases is compressed. The compressed time is not retained from any phase, but is directly deducted from the total cycle duration.

[0201] Similarly, the above Substituting the expression into the above system of equations, we can solve for:

[0202] Furthermore, in order to obtain Then, through the system of equations You can get .

[0203] It should be noted that regardless of the positional relationship between the two control phases, the compressed green light durations of the two phases each satisfy their respective constraints:

[0204]

[0205] The meaning of the above constraints is the same as that of (2) above, and will not be repeated here.

[0206] (5) The calculation of the upstream n-level control intersection scheme is as follows: After completing the scheme calculations for different situations of upstream primary control intersections based on (1)-(4) above, it is also necessary to calculate the traffic volume difference caused by the interception scheme and the increase in the maximum queue length of the upstream road section, so as to prevent new congestion from being caused by the compression of green lights.

[0207] Specifically, refer to Figure 10 The diagram shows a road layout for a multi-level upstream traffic control scenario. It exemplarily shows intersection A, intersection B, and road segments 101, 102, 103, and 104. Intersection B is the primary control intersection upstream of the target congested road segment, and intersection A is the secondary control intersection upstream of intersection B. Road segment 101 represents the increased queue size due to primary traffic control extending upstream, road segment 102 represents the normal queue segment, road segment 103 represents the increased queue size due to secondary traffic control extending upstream, and road segment 104 represents the target congested road segment.

[0208] When Level 1 traffic control is implemented at intersection B, the diverted vehicles will form a new queue in the upstream section of intersection B (i.e., the section between intersection A and intersection B), as shown in section 101. If the increase in queue length exceeds a preset threshold (e.g., more than 40 meters or 20% of the section length), a portion of the control workload needs to be shared with the more upstream intersection A, with Level 2 traffic control jointly undertaking the diversion task. After Level 2 traffic control is implemented, the diverted vehicles will further form a new queue in the upstream section of intersection A, as shown in section 103. This queue increase also needs to be evaluated according to the aforementioned rules to determine whether it is necessary to continue tracing upstream. Through the multi-level traffic control's step-by-step sharing mechanism, the queuing impact is dispersed over a longer section, avoiding excessive concentration of queues at a single upstream intersection and preventing new congestion, while effectively dissipating vehicles in congested section 104. Section 102 represents the original normal queuing state of the upstream section when traffic control is not implemented or the diversion impact has not yet reached.

[0209] Let g be the compressed green light duration of the current level intersection control phase, C be the compressed cycle duration, and the currently running green light duration be... The current cycle duration is The corresponding number of lanes is m, and the saturation headway for each lane is... Then the traffic volume difference in the control flow direction corresponding to the control phase is:

[0210] The aforementioned traffic volume difference reflects the number of vehicles intercepted within a preset unit of time, i.e., 5 minutes. Therefore, the increase in queue length for the corresponding road segment controlled by the traffic flow is:

[0211] in, The number of lanes corresponding to the flow direction. To allow space for queuing vehicles, for example, 7 meters.

[0212] The above formula for the increase in queue length means: traffic volume difference This indicates the total number of vehicles that were diverted due to the green light restriction within 5 minutes. These diverted vehicles will form queues upstream. Multiply by the average space occupied by queuing vehicles (l) to get the total queuing space required for the diverted vehicles, then divide by the number of vehicles (n) on that road segment to get the queue length on a single lane. Because It is a cumulative value over 5 minutes, while queue length is usually measured in signal cycles. Therefore, it is necessary to divide by the number of cycles within 5 minutes, 300 / C, to convert the cumulative queue length into the queue length increment within a single cycle, so as to match and evaluate it with the actual carrying capacity of the road segment.

[0213] Further, select a corresponding control strategy according to the queue length increment : If <0, it indicates that the calculated flow interception scheme is abnormal, that is, the traffic capacity after compression increases instead, and the control schemes of other upstream intersections in the flow direction corresponding to the control phase will not be calculated.

[0214] If the length of the road section corresponding to the controlled flow direction is greater than 1 kilometer, the upstream intersection is far away with poor correlation, and the queue impact caused by flow interception can be effectively absorbed on the long road section, so the control schemes of other upstream intersections will not be calculated.

[0215] If the queue length increment ΔL < max(40, 0.2*L) meters, where L is the length of the upstream road section, it indicates that the queue increase caused by flow interception is within an acceptable range and will not cause new congestion, so the control schemes of other upstream intersections will not be calculated.

[0216] If none of the above conditions are met, it indicates that the flow interception scheme of the current-level intersection will lead to an unacceptable queue length on the upstream road section, and part of the control amount needs to be shared to more upstream intersections to disperse the queue pressure. Let the sharing ratio of the upstream intersection be η (default is 1 / 2), then the control amount to be undertaken by the upstream intersection is: .

[0217] After determining the control flow direction of the upstream intersection (the direction opposite to the flow direction of the current intersection at this intersection is the control flow direction), the above is taken as the traffic volume to be dissipated at this upstream intersection, and the corresponding calculation methods in the foregoing (1) to (4) are returned to calculate its flow interception scheme according to different situations such as constant cycle or variable cycle, one control phase or two control phases. Then the evaluation process of this step (5) is executed again to judge whether it is necessary to continue tracing further upstream.

[0218] The above iterative process continues until the termination condition is met (the queue length increment is less than the threshold, the road section length is greater than 1 kilometer, or a calculation abnormality occurs). Thereby, through the step-by-step sharing of multi-level control intersections, the queue impact caused by flow interception is dispersed to a longer road section range, avoiding the formation of excessively concentrated queues at a single upstream intersection that cause new congestion.

[0219] Through the above scenarios (1)-(5), for the upstream intersection interception control scenario, based on the green light duration, corresponding lane number, saturated headway and cycle duration of the control phase in the current timing scheme, as well as the traffic volume to be dissipated, the green light duration after the control phase compression is determined, realizing the precise compression of the green light duration of the upstream intersection, thereby enabling the rapid generation of interception schemes, effectively reducing the traffic volume entering the congested section, and thus alleviating the input pressure of the upstream intersection on the congested section. At the same time, by setting the constraint that the compressed green light duration is not less than the minimum green light of the corresponding phase, it is ensured that the compression operation will not exceed the bottom line of basic safety requirements such as pedestrian crossing, thus taking into account both traffic efficiency and traffic safety.

[0220] Scenario 2: When the control method is downstream intersection control, the calculation of the green light adjustment amount for the control phase based on the traffic volume to be dissipated, the green light duration, the cycle duration, the number of lanes, and the headway includes: The green light duration after adding the control phase is determined based on the green light duration, corresponding number of lanes, saturation headway, and cycle duration of the control phase in the current timing scheme, as well as the traffic volume to be dissipated.

[0221] The duration of the green light in the control phase after the addition satisfies the constraint that it is not less than the minimum green light duration of the corresponding phase.

[0222] In this step, the green light duration after adding the control phase is determined based on the green light duration, corresponding lane number, saturation headway, and cycle length of the control phase in the current timing scheme, as well as the traffic volume to be dissipated. The added green light duration is the calculated result of the green light adjustment.

[0223] It should be noted that the specific calculation method for the green light adjustment amount in this step varies depending on the actual scenario. Similarly, the situation includes different scenarios such as controlling one or two phases, keeping the cycle unchanged or allowing cycle changes during the adjustment process, and controlling intersections as either first-level or multi-level control intersections.

[0224] For details on whether the cycle should remain unchanged and the specific principles and reasons for determining the control intersection level, please refer to the corresponding explanation in Case 1, which will not be repeated here.

[0225] Furthermore, explanations are provided for different scenarios, such as controlling one or two phases, maintaining a constant cycle or allowing cycle changes during timing adjustments, and controlling intersections as either single-level or multi-level control intersections: (1) When the control flow direction corresponds to a control phase, and the timing scheme maintains a constant period during the adjustment process, the scheme calculation for the downstream level control intersection is as follows: Similar to the upstream intersection traffic control method, let the current green light duration for this phase be... The current cycle duration is The corresponding number of lanes is m, and the saturation headway for each lane is... Let Q be the traffic volume to be dissipated, and g be the duration of the green light after the addition.

[0226] Specifically, the traffic capacity of this phase before its addition = After the addition, the green light duration is changed from If the length is extended to g, then the passage capacity after adding it = Since the period remains unchanged (it is still 100%) The difference in traffic capacity before and after the addition = This capacity difference represents the increase in the number of vehicles per second. Converting this to the cumulative increase in the number of vehicles over 5 minutes (300 seconds), we establish the following equation:

[0227] The extended green light duration can be obtained from this equation. :

[0228] In the above formula, This represents the number of vehicles that need to be added per second, multiplied by the cycle length. The total number of vehicles needed to be added within a period is obtained, and then divided by the sum of the saturation flow rates of each lane. You can then obtain the number of seconds of green light that need to be extended.

[0229] The extended green light duration g must also satisfy the following constraints:

[0230] This constraint sets upper and lower limits for the green light extension. The lower limit is... and The larger of the two values, meaning the added green light duration should be extended by at least 3 seconds, is required to ensure the adjustment is effective; at the same time, it cannot be lower than the minimum green light duration. To ensure basic safety needs such as pedestrians crossing the street. (Upper limit) and The larger of the two values ​​is taken, i.e., a single extension not exceeding 5 seconds or 30% of the current green light duration, to avoid drastic changes in the timing scheme impacting traffic flow. If the calculated value of g exceeds this constraint, the corresponding boundary value is taken as the final result.

[0231] (2) When the control flow corresponds to two control phases, and the timing scheme maintains a constant period during adjustment, the downstream level control intersection scheme is calculated as follows: Similar to the upstream intersection traffic control method, let the current green light duration for phase 1 be... After adding, it becomes The corresponding number of lanes is n, and the headway of each lane is... Phase 2 current green light duration is After adding, it becomes The corresponding number of lanes is m, and the headway of each lane is... The current cycle duration is The traffic volume to be dissipated is Q.

[0232] In this scenario, the passage capacity of the first two phases before addition is as follows: Passage capacity of Phase 1 before addition = Phase 2 before addition of passage capacity = After the addition, the green light duration for phase 1 is changed from... The green light duration for phase 2 is extended to g1. Extended to g2, but the period remains the same. The passage capacity of the two phases remains unchanged, therefore, the passage capacity of phase 1 after adding the extension is as follows: Passage capacity of phase 1 after adding the extension = Traffic capacity after Phase 2 addition = .

[0233] The sum of the increased capacity before and after adding the two phases should equal the traffic volume Q to be dissipated, converted to a capacity value per 5 minutes. Simultaneously, to maintain the time ratio between the two phases consistent with before the addition—that is, to ensure the original green light duration ratio of the two phases is not changed due to the addition operation—the ratio of the green light durations of the two phases after the addition should be equal to the ratio of the green light durations of the two phases before the addition. Based on this, the following system of equations is established:

[0234] The first equation in the above system can be understood as: the increase in capacity of phase 1 plus the increase in capacity of phase 2, multiplied by 300 seconds, equals the traffic volume to be dissipated. The second equation can be understood as: the ratio of the green light duration of the two phases remains the same after the addition as before the addition.

[0235] The expression for the green light duration after adding the two phases can be obtained from this system of equations:

[0236]

[0237] In seeking and Afterwards, it is necessary to verify whether the green light duration after adding the two phases meets the constraints.

[0238] Specifically, the constraints are as follows:

[0239]

[0240] Among the above constraints, the green light duration after the addition of phase 1 The lower limit is taken and The larger of the two values, meaning the added green light duration should be extended by at least 3 seconds, is required to ensure the adjustment is effective; at the same time, it cannot be lower than the minimum green light duration. To ensure that basic safety needs such as pedestrians crossing the street are guaranteed; the upper limit is set at... and The larger of the two options is chosen, i.e., a single extension of no more than 5 seconds or 30% of the current green light duration, to avoid drastic changes in the timing scheme from impacting traffic flow.

[0241] Similarly, the green light duration after phase 2 is added The lower limit is taken and The larger of the two, the upper limit is taken. and The larger of the two. If calculated according to the formula... or If the value exceeds its corresponding constraint range, the corresponding boundary value is taken as the final result; the cycle time after the addition remains unchanged. constant.

[0242] (3) When the control flow corresponds to a control phase and periodic variation is allowed, since there is no need for coordination with other intersections, the total signal cycle duration can be extended by extending the green light duration of that phase; the scheme calculation for downstream level control intersections is as follows: Similar to the upstream intersection traffic control method, let the current green light duration for this phase be... The current cycle duration is The corresponding number of lanes is m, and the saturation headway for each lane is... Let Q be the traffic volume to be dissipated, and g be the duration of the green light after the addition.

[0243] Since the period is variable, the added period duration C becomes: That is, the duration of the added cycle is equal to the original cycle duration plus the green light extension for that phase. This is because when the green light for this phase is extended, the extended time is directly added to the total cycle duration, thus extending the overall cycle length.

[0244] The cycle after the above addition Substituting into the equation for Q established under the condition of constant period in case 2(1) above, that is, the fixed period in the denominator Replace with variable period The following equation can be obtained:

[0245] The physical meaning of this equation is the same as in the case of constant period: the cumulative increase in capacity after the addition of the new capacity over 5 minutes equals the traffic volume Q to be dissipated. The difference lies in the period in the denominator, which is changed from a fixed period to a fixed period. It becomes variable with g. This demonstrates the characteristic that the cycle extends synchronously with the extension of the green light when the cycle is variable.

[0246] Therefore, the extended green light duration can be obtained from the above equation. :

[0247] After obtaining g, the period after adding... This was subsequently determined.

[0248] The extended green light duration g must also satisfy the following constraints:

[0249] This constraint sets upper and lower limits for the green light extension. The lower limit is... and The larger of the two values, meaning the added green light duration should be extended by at least 3 seconds, is required to ensure the adjustment is effective; at the same time, it cannot be lower than the minimum green light duration. To ensure basic safety needs such as pedestrians crossing the street. (Upper limit) and The larger of the two values ​​is taken, i.e., a single extension not exceeding 5 seconds or 30% of the current green light duration, to avoid drastic changes in the timing scheme impacting traffic flow. If the calculated value of g exceeds this constraint, the corresponding boundary value is taken as the final result.

[0250] (4) When the control flow corresponds to two control phases and periodic variation is allowed, since there is no need for coordination with other intersections, the total signal cycle duration can be extended by extending the green light duration of the two phases; the scheme calculation for downstream level control intersections is as follows: Similar to the upstream intersection traffic control method, let the current green light duration for phase 1 be... After compression, it becomes The corresponding number of lanes is n, and the headway of each lane is... Phase 2 current green light duration is After compression, it becomes The corresponding number of lanes is m, and the headway of each lane is... The current cycle duration is The traffic volume to be dissipated is Q.

[0251] In this case, the positional relationship between the two control phases in the signal timing scheme will also affect the calculation method of the post-release cycle duration.

[0252] When two control phases are located in the same barrier but different rings, they run in parallel in time, and the duration of the added period is dominated by the larger of the durations of the two added phases.

[0253] If the green light duration before phase 1 is extended is relatively long (i.e.) ≥ Then, the period after the addition is determined by phase 1, which is equivalent to the original period plus the extension of phase 2: If phase 2 adds a longer green light duration (i.e. < Then, the period after the addition is determined by phase 2, which is equivalent to the original period plus the extension of phase 1: Furthermore, the above two types Substitute the expressions into the following system of equations:

[0254] Furthermore, when ≥ hour, The expression is:

[0255] when < hour, The expression is:

[0256] In seeking Then, through the system of equations You can get .

[0257] When two control phases do not satisfy the positional relationship of being in the same barrier and different loops, they operate in series in time. The duration of the extended cycle is the original cycle plus the sum of the green light extensions of the two phases: That is, the cycle is extended accordingly as the green light duration of the two phases is increased, and the extended time is directly added to the total cycle duration, thus extending the cycle as a whole.

[0258] Similarly, the above Substituting the expression into the above system of equations, we can solve for:

[0259] Furthermore, in order to obtain Then, through the system of equations You can get .

[0260] It should be noted that regardless of the positional relationship between the two control phases, the green light duration after the addition of each phase satisfies its respective constraint conditions:

[0261]

[0262] The meaning of the above constraints is the same as that of case two (2) above, and will not be repeated here.

[0263] (5) The calculation of the downstream n-level control intersection scheme is as follows: After completing the calculation of the downstream primary control intersection based on the above (1)-(4), it is also necessary to calculate the traffic volume difference caused by the additional plan and the increase in the maximum queue length of the downstream road section, so as to prevent new congestion from being caused downstream due to the extension of the green light.

[0264] Specifically, refer to Figure 11 The diagram shows a road layout for a downstream multi-level control scenario. It exemplarily illustrates intersection B, intersection C, and road segments 111 to 116. Intersection B is a primary control intersection downstream of the target congested road segment, and intersection C is a secondary control intersection downstream of intersection B. Road segment 111 represents the target congested road segment, road segment 112 represents the downstream road segment between intersection B and intersection C, road segment 113 represents the road segment further downstream of intersection C, road segment 114 represents the increased queue size caused by the primary control level leading to downstream congestion, road segment 115 represents the normal queue segment, and road segment 116 represents the increased queue size caused by the secondary control level leading to downstream congestion.

[0265] When Level 1 traffic control is implemented at intersection B, the increased capacity will cause more vehicles to exit congested segment 111 and enter downstream segment 112. If the increased queue length formed by these vehicles on segment 112 exceeds a preset threshold (e.g., exceeding 40 meters or 20% of the segment length), a portion of the control load needs to be shared with the more downstream intersection C, where Level 2 traffic control will jointly handle the traffic increase. After Level 2 traffic control is implemented, the increased capacity will further affect segment 113, as shown in segment 116. This queue increase also needs to be evaluated according to the aforementioned rules to determine whether it is necessary to continue tracing downstream. Through the multi-level traffic control mechanism of this step-by-step distribution, the increased capacity generated by the traffic increase is dispersed to a longer segment, avoiding excessive concentration of queues at a single downstream intersection and preventing new congestion, while effectively dissipating vehicles from congested segment 111. Section 115 indicates the normal queuing status of the downstream section before any additional control measures were implemented or before any impact from additional controls was felt.

[0266] Similar to the upstream intersection traffic control method, let the compressed green light duration of the current level intersection control phase be g, the compressed cycle duration be C, and the currently running green light duration be... The current cycle duration is The corresponding number of lanes is m, and the saturation headway for each lane is... Then the traffic volume difference in the control flow direction corresponding to the control phase is:

[0267] The aforementioned traffic volume difference reflects the increase in the number of vehicles due to the extended green light within 5 minutes. Therefore, the increase in queue length for the corresponding downstream road segment is:

[0268] in, The number of lanes corresponding to the flow direction. To allow space for queuing vehicles, for example, 7 meters.

[0269] The above formula for the increase in queue length means: traffic volume difference This indicates the number of vehicles that have increased due to the extended green light within 5 minutes. These additional vehicles will enter the downstream section of the road and may form new queues. Multiplying by the average space occupied by queuing vehicles (l) gives the total queuing space required to add more vehicles. Dividing this by the number of lanes (n) on that road segment gives the queue length per lane. Because... It is a cumulative value over 5 minutes, while queue length is usually measured in signal cycles. Therefore, it is necessary to divide by the number of cycles within 5 minutes, 300 / C, to convert the cumulative queue length into the queue length increment within a single cycle, so as to match and evaluate it with the actual carrying capacity of the road segment.

[0270] Furthermore, based on the increment of queue length Size selection corresponds to the control strategy: like If the value is less than 0, it indicates that the calculated addition scheme is abnormal (i.e., the traffic capacity is reduced after the addition), and the control scheme for other downstream intersections corresponding to the control phase is no longer calculated.

[0271] If the length of the downstream road segment corresponding to the controlled flow direction is greater than 1 kilometer, the downstream intersections are far apart and have poor correlation, so control schemes for other downstream intersections will not be calculated.

[0272] If the queue length increment ΔL <max(40,0.2 If L)m meters (where L is the length of the downstream road segment), then the increase in queuing caused by adding the road segment is within an acceptable range, and control schemes for other downstream intersections will not be calculated.

[0273] If none of the above conditions are met, it indicates that the current-level intersection addition scheme will result in unacceptable queue lengths in downstream road segments, requiring the allocation of some control load to more downstream intersections. Let the allocation ratio for downstream intersections be η (default is 1 / 2), then the control load that downstream intersections need to bear is: .

[0274] After determining the control flow direction at the downstream intersection, as described above As the traffic volume to be dissipated at the downstream intersection, return to the calculation methods in (1) to (4) above, and calculate the additional release scheme according to different situations such as unchanged cycle or variable cycle, one control phase or two control phases. Then, perform the evaluation process of step (5) again to determine whether it is necessary to continue to trace further downstream.

[0275] The above iterative process continues until the termination condition is met (the queue length increment is less than the threshold, the road segment length is greater than 1 kilometer, or a calculation anomaly occurs). Thus, by controlling the load at multiple levels of intersections, the impact of the increased capacity on downstream areas is dispersed over a longer road segment, avoiding excessively concentrated queues at a single downstream intersection that could trigger new congestion.

[0276] Through (1)-(5) of the above-mentioned second scenario, for the downstream intersection control addition scenario, the green light duration after the control phase is added is determined based on the green light duration, corresponding lane number, saturated headway and cycle duration of the control phase in the current timing scheme, as well as the traffic volume to be dissipated, thus achieving a precise extension of the green light duration at the downstream intersection. This scheme can quickly generate the addition scheme, effectively increase the traffic capacity to exit congested road sections, and accelerate the dissipation of congested vehicles; by setting the constraint that the green light duration after the addition is not less than the minimum green light of the corresponding phase, it is ensured that the extension operation will not infringe on the basic safety needs of pedestrians crossing the street.

[0277] Scenario 3: When the control method is upstream intersection traffic control and downstream intersection traffic increase control, the calculation of the green light adjustment amount for the control phase based on the traffic volume to be dissipated, the green light duration, the cycle duration, the number of lanes, and the headway includes: Step c1: Allocate the traffic volume to be dissipated into interception control volume and release control volume.

[0278] When both upstream traffic diversion and downstream traffic release are used to control congested road sections, the overall control task is reasonably divided into two parts: traffic diversion and traffic release, so as to guide the timing adjustment of upstream and downstream intersections respectively.

[0279] In practice, the actual traffic flow of the congested road segment in the upstream interception direction and the downstream addition direction is first obtained within a preset historical time period (e.g., the most recent 15 minutes). This traffic flow data reflects the current distribution of traffic demand in both upstream and downstream directions and can be used as a basis for allocating control volumes.

[0280] Then, based on the actual traffic flow ratio between the upstream interception direction and the downstream release direction, the traffic volume Q to be dissipated is allocated as the interception control volume. and add control amount ; and The calculation formula is as follows:

[0281]

[0282] in, This indicates the actual traffic flow of the upstream intercepted flow within a preset historical time period, that is, the number of vehicles entering the congested section from the upstream intersection. This represents the actual traffic flow downstream within a preset historical time period, i.e., the number of vehicles exiting the congested section and reaching the downstream intersection. Furthermore, the traffic volume Q to be dissipated is calculated according to... and The proportion of control is allocated so that the allocation of control volume matches the actual traffic demand. That is, the direction with higher traffic volume undertakes more control tasks, thereby avoiding overly intensive control in one direction and insufficient control in another.

[0283] In some embodiments, a preset fixed ratio or a ratio based on the difference in traffic capacity between the upstream and downstream of the congested road segment can also be used for allocation.

[0284] Step c2: Using the traffic diversion control amount as the traffic volume to be dissipated, calculate the green light adjustment amount for each control phase upstream according to the method described in claim 7.

[0285] Furthermore, the flow control quantity was determined in step c1. Then, this step uses the controlled volume as the traffic volume to be dissipated at the upstream intersection, and determines the green light duration that needs to be compressed for each control phase upstream according to the calculation method of traffic diversion control.

[0286] Specifically, as mentioned above As the traffic volume to be dissipated at the upstream control intersection, the calculation is performed according to the actual timing scheme parameters of the intersection, including the current green light duration, corresponding lane number, saturated headway, cycle duration, etc. of each control phase, following the method described in steps (1) to (5) of the aforementioned case one. That is, depending on different situations such as whether the number of control phases is one or two, whether the timing scheme keeps the cycle unchanged or allows cycle changes, and whether the control intersection is a first-level control intersection or a multi-level control intersection, the corresponding calculation method is adopted to determine the compressed green light duration of each control phase. The compressed green light duration must meet the constraint condition of not being less than the minimum green light of the corresponding phase.

[0287] In the case where there are multiple control intersections upstream (i.e., multi-level interception control is required), the control quantity is traced upstream level by level and allocated according to the scheme calculation method of upstream n-level control intersections in the aforementioned step (5) until the termination condition is met.

[0288] Step c3: Using the added control amount as the traffic volume to be dissipated, calculate the green light adjustment amount for each downstream control phase according to the method described in claim 8.

[0289] The control amount for adding or removing was determined in step c1. Then, this step uses the controlled volume as the traffic volume to be dissipated at the downstream intersection, and determines the green light duration that needs to be extended for each downstream control phase according to the calculation method for adding control.

[0290] Specifically, with the above As the traffic volume to be dissipated at the downstream controlled intersection, the calculation is performed according to the actual timing scheme parameters of the intersection, following the methods described in steps (1) to (5) of the aforementioned second scenario. That is, depending on different situations such as whether the number of control phases is one or two, whether the timing scheme keeps the cycle unchanged or allows cycle changes, and whether the controlled intersection is a first-level controlled intersection or a multi-level controlled intersection, the corresponding calculation method is adopted to determine the green light duration after the addition of each control phase. The green light duration after the addition must meet the constraint condition of not being less than the minimum green light of the corresponding phase.

[0291] In the case where there are multiple control intersections downstream (i.e., multiple levels of control need to be added), the control quantity is traced and allocated downstream level by level according to the calculation method of the downstream n-level control intersection in the aforementioned step (5) until the termination condition is met.

[0292] Based on the above scenario three, for the combined control situation requiring both upstream interception and downstream release control methods in severe congestion scenarios, the traffic volume to be dissipated is allocated into interception control volume and release control volume. The green light adjustment amounts for each control phase upstream and downstream are calculated according to the methods in scenarios one and two, respectively. This achieves bidirectional coordinated control by reducing upstream inflows and increasing downstream outflows. Compared to a single control method, this approach can exert force simultaneously from both ends of the congested road segment, enabling faster and more effective dissipation of queuing vehicles within a unit of time. Furthermore, by allocating the total control volume according to actual traffic demand, the adverse effects of excessive control volume in one direction are avoided, improving the rationality and practical effectiveness of the control scheme. This approach can effectively address severe congestion scenarios caused by rapid increases in traffic flow during peak hours.

[0293] Figure 12 This is a schematic diagram of a traffic signal control device provided in an embodiment of the present disclosure. The device is configured in a computer device and can implement the traffic signal control method described in any embodiment of the present disclosure. The traffic signal control device 1200 specifically includes the following: The acquisition unit 1201 is used to acquire the target congested road segment and the road segment status of the target congested road segment; The calculation unit 1202 is used to calculate, under the current intersection signal timing scheme, the outbound traffic capacity of the downstream intersection corresponding to the target congested road segment in a preset unit time, and the inbound traffic capacity of the upstream intersection in the same preset unit time. Processing unit 1203 is used to calculate the difference between the inbound traffic capacity and the outbound traffic capacity to obtain the traffic capacity difference of the target congested road segment; The determining unit 1204 is used to determine the target control method for the target congested road segment based on the traffic capacity difference and the road segment status; the target control method is: upstream intersection traffic interception control and / or downstream intersection traffic release control; The generation unit 1205 is used to generate and execute the target intersection signal timing scheme corresponding to the target congested road segment based on the target control method and the traffic volume to be dissipated in the target congested road segment. The traffic volume to be dissipated is represented as the total number of vehicles queuing on the target congested road section that are reduced through control measures within the preset unit time.

[0294] The traffic signal control device provided in this disclosure can execute the traffic signal control method provided in any embodiment of this disclosure, and has the corresponding functional modules and beneficial effects of the method. To avoid repetition, it will not be described again here.

[0295] This disclosure provides a computer device, including: one or more processors; and a storage device for storing one or more programs, which, when executed by the one or more processors, cause the one or more processors to implement any of the traffic signal control methods described in this disclosure.

[0296] Figure 13 This is a schematic diagram of the structure of a computer device provided in an embodiment of this disclosure. Figure 13 As shown, the computer device includes a processor 1310 and a storage device 1320; the number of processors 1310 in the computer device can be one or more. Figure 13 Taking a processor 1310 as an example; the processor 1310 and the storage device 1320 in a computer device can be connected via a bus or other means. Figure 13 Taking the example of a connection between China and Israel via a bus.

[0297] Storage device 1320, as a computer-readable storage medium, can be used to store software programs, computer-executable programs, and modules, such as the program instructions / modules corresponding to the traffic signal control method in the embodiments of this disclosure. Processor 1310 executes various functional applications and data processing of computer devices by running the software programs, instructions, and modules stored in storage device 1320, thereby realizing the traffic signal control method provided in the embodiments of this disclosure.

[0298] Storage device 1320 may primarily include a stored program area and a stored data area. The stored program area may store the operating system and at least one application program required for a given function; the stored data area may store data created based on terminal usage. Furthermore, storage device 1320 may include a high-speed random access storage device, and may also include a non-volatile storage device, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some instances, storage device 1320 may further include storage devices remotely located relative to processor 1310, which can be connected to computer equipment via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0299] The computer device provided in this embodiment can be used to execute the traffic signal control method provided in any of the above embodiments, and has corresponding functions and beneficial effects.

[0300] This disclosure also provides a storage medium containing computer-executable instructions. When executed by a computer processor, the computer-executable instructions implement the various processes of the methods provided in any of the above embodiments and achieve the same technical effects. To avoid repetition, further details are omitted here.

[0301] The computer-readable storage medium can be a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, etc.

[0302] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the discussion in some embodiments above is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and practical applications, thereby enabling those skilled in the art to better utilize the embodiments and various different variations of the embodiments suitable for specific application considerations.

Claims

1. A method for controlling traffic signals, characterized in that, include: Obtain the target congested road segment and its road segment status; Calculate the outbound traffic capacity of the downstream intersection corresponding to the target congested road segment in a preset unit time, and the inbound traffic capacity of the upstream intersection in the same preset unit time, under the current intersection signal timing scheme. The difference between the inbound traffic capacity and the outbound traffic capacity is calculated to obtain the traffic capacity difference of the target congested road segment; Based on the poor traffic capacity and the road segment status, the target control method for the target congested road segment is determined; the target control method is: upstream intersection traffic control and / or downstream intersection traffic control. Based on the target control method and the traffic volume to be dissipated in the target congested road segment, a target intersection signal timing scheme corresponding to the target congested road segment is generated and executed; The traffic volume to be dissipated is represented as the total number of vehicles queuing on the target congested road section that are reduced through control measures within the preset unit time.

2. The method according to claim 1, characterized in that, The acquisition of the target congested road segment includes: Acquire real-time traffic data for each road segment in the urban road network, and determine the status of each road segment based on the real-time traffic data; Based on the road segment status of each road segment, the target congested road segment is obtained.

3. The method according to claim 1, characterized in that, The calculation, under the current intersection signal timing scheme, of the outbound traffic capacity of the downstream intersection corresponding to the target congested road segment within a preset unit time, and the inbound traffic capacity of the upstream intersection within the same preset unit time, includes: For downstream intersections, obtain the cycle duration under the current intersection signal timing scheme, the green light duration of the control phase corresponding to the outbound direction of the target congested road segment, and the saturation headway and number of lanes for the corresponding lanes; The exit capacity is calculated based on the ratio of the green light duration to the cycle duration, the saturation headway, and the number of lanes. For the upstream intersection, obtain the cycle duration under the current intersection signal timing scheme, the green light duration of the control phase corresponding to the direction of entry of the target congested road segment, and the saturation headway and number of lanes of the corresponding lane; The entry capacity is calculated based on the ratio of the green light duration to the cycle duration, the saturation headway, and the number of lanes.

4. The method according to claim 1, characterized in that, The method for determining the target control mechanism for the target congested road segment based on the traffic capacity difference and the road segment status includes: If the difference in traffic capacity is less than or equal to zero, then the upstream intersection interception method will be used for control. If the difference in traffic capacity is greater than zero and the road segment is in a congested state, then it is determined that the downstream intersection access method will be used for control. If the traffic capacity difference is greater than zero and the road segment is in a state of severe congestion, then it is determined that the downstream intersection traffic control and the upstream intersection traffic interception control will be implemented in parallel.

5. The method according to claim 1, characterized in that, Before determining and implementing the intersection signal timing adjustment scheme corresponding to the target congested road segment based on the control method and the traffic volume to be dissipated in the congested road segment, the method further includes: Obtain the congestion length and number of lanes of the target congested road segment; The traffic volume to be dispersed is calculated based on the congestion length, the number of lanes, and the congestion dissipation rate per unit time.

6. The method according to claim 1, characterized in that, The step of generating and executing a target intersection signal timing scheme corresponding to the target congested road segment based on the target control method and the traffic volume to be dissipated in the target congested road segment includes: The control intersections and corresponding control flow directions are determined based on the target control method. Based on the current signal timing scheme of the controlled intersection, determine the control phase corresponding to the control flow direction and the green light duration, cycle duration, number of lanes and headway of the control phase in the current timing scheme; The green light adjustment amount of the control phase is calculated based on the traffic volume to be dissipated, the green light duration, the cycle duration, the number of lanes, and the headway. The signal timing scheme for the current intersection is adjusted according to the green light adjustment amount, and the signal timing scheme for the target intersection is generated and executed.

7. The method according to claim 6, characterized in that, When the target control method is upstream intersection traffic control, the calculation of the green light adjustment amount of the control phase based on the traffic volume to be dissipated, the green light duration, the cycle duration, the number of lanes, and the headway includes: The green light duration after the control phase compression is determined based on the green light duration, corresponding number of lanes, saturated headway, cycle duration of the control phase in the current timing scheme, and the traffic volume to be dissipated. The compressed green light duration of the control phase satisfies the constraint that it is not less than the minimum green light duration of the corresponding phase.

8. The method according to claim 6, characterized in that, When the target control method is downstream intersection control, the step of calculating the green light adjustment amount of the control phase based on the traffic volume to be dissipated, the green light duration, the cycle duration, the number of lanes, and the headway includes: The green light duration after adding the control phase is determined based on the green light duration, corresponding number of lanes, saturation headway, and cycle duration of the control phase in the current timing scheme, as well as the traffic volume to be dissipated. The duration of the green light in the control phase after the addition satisfies the constraint that it is not less than the minimum green light duration of the corresponding phase.

9. The method according to claim 6, characterized in that, When the control method is upstream intersection traffic control and downstream intersection traffic increase control, the calculation of the green light adjustment amount of the control phase based on the traffic volume to be dissipated, the green light duration, the cycle duration, the number of lanes, and the headway includes: The traffic volume to be dispersed is allocated into a diversion control volume and an additional release control volume; Using the traffic diversion control amount as the traffic volume to be dissipated, calculate the green light adjustment amount for each control phase upstream according to the method described in claim 7; Using the added control amount as the traffic volume to be dissipated, the green light adjustment amount for each downstream control phase is calculated according to the method described in claim 8.

10. A traffic signal control device, characterized in that, include: The acquisition unit is used to acquire the target congested road segment and the road segment status of the target congested road segment; The calculation unit is used to calculate the outbound traffic capacity of the downstream intersection corresponding to the target congested road segment in a preset unit time, and the inbound traffic capacity of the upstream intersection in the same preset unit time, under the current intersection signal timing scheme. The processing unit is used to calculate the difference between the inbound traffic capacity and the outbound traffic capacity to obtain the traffic capacity difference of the target congested road segment; The determining unit is used to determine the target control method for the target congested road segment based on the traffic capacity difference and the road segment status; the target control method is: upstream intersection traffic control and / or downstream intersection traffic control. The generation unit is used to generate and execute the target intersection signal timing scheme corresponding to the target congested road segment based on the target control method and the traffic volume to be dissipated in the target congested road segment. The traffic volume to be dissipated is represented as the total number of vehicles queuing on the target congested road section that are reduced through control measures within the preset unit time.

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